The TOSCA Simple Profile in YAML specifies a rendering of
TOSCA which aims to provide a more accessible syntax as well as a more concise
and incremental expressiveness of the TOSCA DSL in order to minimize the
learning curve and speed the adoption of the use of TOSCA to portably describe
cloud applications.
This proposal describes a YAML rendering for TOSCA. YAML is
a human friendly data serialization standard (http://yaml.org/)
with a syntax much easier to read and edit than XML. As there are a number of
DSLs encoded in YAML, a YAML encoding of the TOSCA DSL makes TOSCA more
accessible by these communities.
This proposal prescribes an isomorphic rendering in YAML of
a subset of the TOSCA v1.0 XML specification ensuring that TOSCA semantics are
preserved and can be transformed from XML to YAML or from YAML to XML.
Additionally, in order to streamline the expression of TOSCA semantics, the
YAML rendering is sought to be more concise and compact through the use of the
YAML syntax.
The TOSCA metamodel uses the
concept of service templates to describe cloud workloads as a topology
template, which is a graph of node templates modeling the components a workload
is made up of and as relationship templates modeling the relations between
those components. TOSCA further provides a type system of node types to
describe the possible building blocks for constructing a service template, as
well as relationship type to describe possible kinds of relations. Both node
and relationship types may define lifecycle operations to implement the
behavior an orchestration engine can invoke when instantiating a service
template. For example, a node type for some software product might provide a
‘create’ operation to handle the creation of an instance of a component at
runtime, or a ‘start’ or ‘stop’ operation to handle a start or stop event
triggered by an orchestration engine. Those lifecycle operations are backed by
implementation artifacts such as scripts or Chef recipes that implement the
actual behavior.
An orchestration engine
processing a TOSCA service template uses the mentioned lifecycle operations to
instantiate single components at runtime, and it uses the relationship between
components to derive the order of component instantiation. For example, during
the instantiation of a two-tier application that includes a web application
that depends on a database, an orchestration engine would first invoke the
‘create’ operation on the database component to install and configure the
database, and it would then invoke the ‘create’ operation of the web
application to install and configure the application (which includes
configuration of the database connection).
The TOSCA simple profile
assumes a number of base types (node types and relationship types) to be
supported by each compliant environment such as a ‘Compute’ node type, a
‘Network’ node type or a generic ‘Database’ node type. Furthermore, it is
envisioned that a large number of additional types for use in service templates
will be defined by a community over time. Therefore, template authors in many
cases will not have to define types themselves but can simply start writing
service templates that use existing types. In addition, the simple profile will
provide means for easily customizing and extending existing types, for example
by providing a customized ‘create’ script for some software.
Different kinds of processors
and artifacts qualify as implementations of the TOSCA simple profile. Those
that this specification is explicitly mentioning or referring to fall into the
following categories:
·
TOSCA YAML service template (or “service template”): A YAML
document artifact containing a (TOSCA) service template (see sections 3.9
“Service template definition”) that represents a Cloud application. (see
sections 3.8 “Topology template definition”)
·
TOSCA processor (or “processor”): An engine or tool that is
capable of parsing and interpreting a TOSCA service template for a particular
purpose. For example, the purpose could be validation, translation or visual
rendering.
·
TOSCA orchestrator (also called orchestration engine): A TOSCA
processor that interprets a TOSCA service template or a TOSCA CSAR in order to
instantiate and deploy the described application in a Cloud.
·
TOSCA generator: A tool that generates a TOSCA service template.
An example of generator is a modeling tool capable of generating or editing a
TOSCA service template (often such a tool would also be a TOSCA processor).
·
TOSCA archive (or TOSCA Cloud Service Archive, or “CSAR”): a
package artifact that contains a TOSCA service template and other artifacts
usable by a TOSCA orchestrator to deploy an application.
The above list is not
exclusive. The above definitions should be understood as referring to and
implementing the TOSCA simple profile as described in this document
(abbreviated here as “TOSCA” for simplicity).
The TOSCA language introduces a YAML grammar for describing
service templates by means of Topology Templates and towards enablement of
interaction with a TOSCA instance model perhaps by external APIs or plans. The
primary currently is on design time aspects, i.e. the description of services
to ensure their exchange between Cloud providers, TOSCA Orchestrators and
tooling.
The language provides an extension mechanism that can be
used to extend the definitions with additional vendor-specific or domain-specific
information.
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”,
“SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in
this document are to be interpreted as described in [RFC2119].
·
Sections that are titled “Example” throughout this document are
considered non-normative.
|
[RFC2119]
|
S. Bradner, Key words for use in RFCs to Indicate Requirement
Levels, http://www.ietf.org/rfc/rfc2119.txt,
IETF RFC 2119, March 1997.
|
|
[TOSCA-1.0]
|
Topology and Orchestration Topology and Orchestration
Specification for Cloud Applications (TOSCA) Version 1.0, an OASIS Standard,
25 November 2013, http://docs.oasis-open.org/tosca/TOSCA/v1.0/os/TOSCA-v1.0-os.pdf
|
|
[YAML-1.2]
|
YAML, Version 1.2, 3rd Edition, Patched at 2009-10-01, Oren Ben-Kiki,
Clark Evans, Ingy döt Net http://www.yaml.org/spec/1.2/spec.html
|
|
[YAML-TS-1.1]
|
Timestamp Language-Independent Type for YAML Version 1.1,
Working Draft 2005-01-18, http://yaml.org/type/timestamp.html
|
The following terms are used throughout this
specification and have the following definitions when used in context of this
document.
|
Term
|
Definition
|
|
Instance Model
|
A deployed service is a running instance of a Service
Template. More precisely, the instance is derived by instantiating the
Topology Template of its Service Template, most often by running a special
plan defined for the Service Template, often referred to as build plan.
|
|
Node Template
|
A Node Template specifies the occurrence of a
software component node as part of a Topology Template. Each Node Template
refers to a Node Type that defines the semantics of the node (e.g.,
properties, attributes, requirements, capabilities, interfaces). Node Types
are defined separately for reuse purposes.
|
|
Relationship Template
|
A Relationship Template specifies the occurrence of
a relationship between nodes in a Topology Template. Each Relationship
Template refers to a Relationship Type that defines the semantics
relationship (e.g., properties, attributes, interfaces, etc.). Relationship
Types are defined separately for reuse purposes.
|
|
Service
Template
|
A Service Template is typically used to specify the
“topology” (or structure) and “orchestration” (or invocation of management
behavior) of IT services so that they can be provisioned and managed in
accordance with constraints and policies.
Specifically, TOSCA Service Templates optionally allow
definitions of a TOSCA Topology Template,
TOSCA types (e.g., Node, Relationship, Capability, Artifact, etc.),
groupings, policies and constraints along with any input or output
declarations.
|
|
Topology
Model
|
The term Topology Model is often used synonymously with the term
Topology Template with the use of
“model” being prevalent when considering a Service Template’s topology
definition as an abstract representation of an
application or service to facilitate understanding of its functional
components and by eliminating unnecessary details.
|
|
Topology
Template
|
A Topology Template defines the structure of a service in the
context of a Service Template. A Topology Template consists of a set of Node
Template and Relationship Template definitions that together define the
topology model of a service as a (not necessarily connected) directed graph.
The term Topology Template is often used synonymously with the
term Topology Model. The distinction is
that a topology template can be used to instantiate and orchestrate the model
as a reusable pattern and includes all details necessary to
accomplish it.
|
|
Abstract Node Template
|
An abstract node template is a node that doesn’t define an
implementation artifact for the create operation of the TOSCA lifecycle.
The create operation can be delegated to the TOSCA Orchestrator.
Being delegated an abstract node may not be able to execute user
provided implementation artifacts for operations post create (for example
configure, start etc.).
|
|
No-Op Node Template
|
A No-Op node template is a specific abstract node template that
does not specify any implementation for any operation.
|
|
|
|
This non-normative section contains several sections
that show how to model applications with TOSCA Simple Profile using YAML by
example starting with a “Hello World” template up through examples that show
complex composition modeling.
2.1 A “hello world” template for TOSCA Simple
Profile in YAML
As mentioned before, the TOSCA
simple profile assumes the existence of a small set of pre-defined, normative
set of node types (e.g., a ‘Compute’ node) along with other types, which will
be introduced through the course of this document, for creating TOSCA Service
Templates. It is envisioned that many additional node types for building
service templates will be created by communities some may be published as
profiles that build upon the TOSCA Simple Profile specification. Using the normative
TOSCA Compute node type, a very basic “Hello World” TOSCA template for
deploying just a single server would look as follows:
Example 1
- TOSCA Simple "Hello World"
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying a single server with predefined properties.
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
# Host container properties
host:
properties:
num_cpus: 1
disk_size: 10 GB
mem_size: 4096 MB
# Guest Operating System properties
os:
properties:
# host Operating System image properties
architecture: x86_64
type: linux
distribution: rhel
version: 6.5
|
The template above contains a very simple topology
template with only a single ‘Compute’ node template that declares some basic
values for properties within two of the several capabilities that are built
into the Compute node type definition. All TOSCA Orchestrators are expected to
know how to instantiate a Compute node since it is normative and expected to
represent a well-known function that is portable across TOSCA implementations.
This expectation is true for all normative TOSCA Node and Relationship types
that are defined in the Simple Profile specification. This means, with TOSCA’s
approach, that the application developer does not need to provide any
deployment or implementation artifacts that contain code or logic to
orchestrate these common software components. TOSCA orchestrators simply
select or allocate the correct node (resource) type that fulfills the
application topologies requirements using the properties declared in the node
and its capabilities.
In the above example, the “host”
capability contains properties that allow application developers to optionally
supply the number of CPUs, memory size and disk size they believe they need
when the Compute node is instantiated in order to run their applications.
Similarly, the “os” capability is used
to provide values to indicate what host operating system the Compute node
should have when it is instantiated.
The logical diagram of the “hello world” Compute node would
look as follows:
As you can see, the Compute
node also has attributes and other built-in capabilities, such as Bindable and Endpoint, each with additional properties
that will be discussed in other examples later in this document. Although the
Compute node has no direct properties apart from those in its capabilities,
other TOSCA node type definitions may have properties that are part of the node
type itself in addition to having Capabilities. TOSCA orchestration engines
are expected to validate all property values provided in a node template
against the property definitions in their respective node type definitions
referenced in the service template. The tosca_definitions_version
keyname in the TOSCA service template identifies the versioned set of
normative TOSCA type definitions to use for validating those types defined in
the TOSCA Simple Profile including the Compute node type. Specifically, the
value tosca_simple_yaml_1_0 indicates
Simple Profile v1.0.0 definitions would be used for validation. Other type
definitions may be imported from other service templates using the import keyword discussed later.
Typically, one would want to
allow users to customize deployments by providing input parameters instead of
using hardcoded values inside a template. In addition, output values are provided
to pass information that perhaps describes the state of the deployed template
to the user who deployed it (such as the private IP address of the deployed
server). A refined service template with corresponding inputs and outputs
sections is shown below.
Example 2 - Template with
input and output parameter sections
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying a single server with predefined properties.
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
# Host container
properties
host:
properties:
# Compute properties
num_cpus: { get_input:
cpus }
mem_size: 2048 MB
disk_size: 10 GB
outputs:
server_ip:
description: The private IP
address of the provisioned server.
value: { get_attribute: [
my_server, private_address ] }
|
The inputs
and outputs sections are contained in
the topology_template element of the
TOSCA template, meaning that they are scoped to node templates within the
topology template. Input parameters defined in the inputs section can be
assigned to properties of node template within the containing topology
template; output parameters can be obtained from attributes of node templates
within the containing topology template.
Note that the inputs
section of a TOSCA template allows for defining optional constraints on each
input parameter to restrict possible user input. Further note that TOSCA
provides for a set of intrinsic functions like get_input, get_property
or get_attribute to reference elements
within the template or to retrieve runtime values.
2.2 TOSCA template for a simple software
installation
Software installations can be modeled in TOSCA as node
templates that get related to the node template for a server on which the
software would be installed. With a number of existing software node types
(e.g. either created by the TOSCA work group or a community) template authors
can just use those node types for writing service templates as shown below.
Example 3 - Simple (MySQL) software installation on a
TOSCA Compute node
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying a single server with MySQL software on top.
topology_template:
inputs:
# omitted here for brevity
node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: {
get_input: my_mysql_rootpw }
port: { get_input:
my_mysql_port }
requirements:
- host: db_server
db_server:
type: tosca.nodes.Compute
capabilities:
# omitted here for brevity
|
The example above makes use of a node type tosca.nodes.DBMS.MySQL for the mysql node template to install MySQL on a
server. This node type allows for setting a property root_password to adapt the password of the
MySQL root user at deployment. The set of properties and their schema has been
defined in the node type definition. By means of the get_input function, a value provided by the user at
deployment time is used as value for the root_password
property. The same is true for the port
property.
The mysql node template is related to the db_server node template (of type tosca.nodes.Compute) via the requirements section to indicate where
MySQL is to be installed. In the TOSCA metamodel, nodes get related to each
other when one node has a requirement against some feature provided by another
node. What kinds of requirements exist is defined by the respective node type.
In case of MySQL, which is software that needs to be installed or hosted on a
compute resource, the underlying node type named DBMS has a predefined requirement called host, which needs to be fulfilled by
pointing to a node template of type tosca.nodes.Compute.
The
logical relationship between the mysql
node and its host db_server node would
appear as follows:
Within the requirements section, all entries simple
entries are a map which contains the symbolic name of a requirement definition
as the key and the identifier of the fulfilling node as the value. The
value is essentially the symbolic name of the other node template;
specifically, or the example above, the host
requirement is fulfilled by referencing the db_server
node template. The underlying TOSCA DBMS
node type already defines a complete requirement definition for the host requirement of type Container and assures that a HostedOn TOSCA relationship will
automatically be created and will only allow a valid target host node is of
type Compute. This approach allows the
template author to simply provide the name of a valid Compute node (i.e., db_server) as the value for the mysql node’s host requirement and not worry about defining
anything more complex if they do not want to.
Node types in TOSCA have
associated implementations that provide the automation (e.g. in the form of
scripts such as Bash, Chef or Python) for the normative lifecycle operations of
a node. For example, the node type implementation for a MySQL database would
associate scripts to TOSCA node operations like configure, start,
or stop to manage the state of MySQL at
runtime.
Many node types may already
come with a set of operational scripts that contain basic commands that can
manage the state of that specific node. If it is desired, template authors can
provide a custom script for one or more of the operation defined by a node type
in their node template which will override the default implementation in the
type. The following example shows a mysql
node template where the template author provides their own configure script:
Example 4 - Node Template overriding its Node Type's
"configure" interface
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying a single server with MySQL software on top.
topology_template:
inputs:
# omitted here for brevity
node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: {
get_input: my_mysql_rootpw }
port: { get_input:
my_mysql_port }
requirements:
- host: db_server
interfaces:
Standard:
configure: scripts/my_own_configure.sh
db_server:
type: tosca.nodes.Compute
capabilities:
# omitted here for brevity
|
In the example above, the my_own_configure.sh script is provided for
the configure operation of the MySQL
node type’s Standard lifecycle
interface. The path given in the example above (i.e., ‘scripts/’) is
interpreted relative to the template file, but it would also be possible to
provide an absolute URI to the location of the script.
In other words, operations
defined by node types can be thought of as “hooks” into which automation can be
injected. Typically, node type implementations provide the automation for those
“hooks”. However, within a template, custom automation can be injected to run
in a hook in the context of the one, specific node template (i.e. without
changing the node type).
In the Example 4, shown above,
the deployment of the MySQL middleware only, i.e. without actual database
content was shown. The following example shows how such a template can be
extended to also contain the definition of custom database content on-top of
the MySQL DBMS software.
Example 5 - Template for deploying database content
on-top of MySQL DBMS middleware
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying MySQL and database content.
topology_template:
inputs:
# omitted here for brevity
node_templates:
my_db:
type: tosca.nodes.Database.MySQL
properties:
name: { get_input:
database_name }
user: { get_input:
database_user }
password: { get_input:
database_password }
port: { get_input:
database_port }
artifacts:
db_content:
file: files/my_db_content.txt
type:
tosca.artifacts.File
requirements:
- host: mysql
interfaces:
Standard:
create:
implementation:
db_create.sh
inputs:
# Copy DB file
artifact to server’s staging area
db_data: { get_artifact: [
SELF, db_content ] }
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: {
get_input: mysql_rootpw }
port: { get_input:
mysql_port }
requirements:
- host: db_server
db_server:
type: tosca.nodes.Compute
capabilities:
# omitted here for brevity
|
In the example above, the my_db node template or type tosca.nodes.Database.MySQL represents an
actual MySQL database instance managed by a MySQL DBMS installation. The requirements section of the my_db node template expresses that the
database it represents is to be hosted on a MySQL DBMS node template named mysql which is also declared in this
template.
In its artifacts section of the my_db the node template, there is an artifact
definition named db_content which
represents a text file my_db_content.txt
which in turn will be used to add content to the SQL database as part of the create operation. The requirements
section of the my_db node template expresses that the database is hosted
on a MySQL DBMS represented by the mysql node.
As you can see above, a script is associated with the create
operation with the name db_create.sh.
The TOSCA Orchestrator sees that this is not a named artifact declared in the
node’s artifact section, but instead a filename for a normative TOSCA
implementation artifact script type (i.e., tosca.artifacts.Implementation.Bash).
Since this is an implementation type for TOSCA, the orchestrator will execute
the script automatically to create the node on db_server, but first it will prepare the
local environment with the declared inputs for the operation. In this case, the
orchestrator would see that the db_data
input is using the get_artifact
function to retrieve the file (my_db_content.txt)
which is associated with the db_content
artifact name prior to executing the db_create.sh
script.
The logical diagram for this example would appear as
follows:
Note that while it would be
possible to define one node type and corresponding node templates that
represent both the DBMS middleware and actual database content as one entity,
TOSCA normative node types distinguish between middleware (container) and
application (containee) node types. This allows on one hand to have better
re-use of generic middleware node types without binding them to content running
on top of them, and on the other hand this allows for better substitutability
of, for example, middleware components like a DBMS during the deployment of
TOSCA models.
The definition of multi-tier
applications in TOSCA is quite similar to the example shown in section 2.2, with the only difference that multiple software node stacks (i.e., node
templates for middleware and application layer components), typically hosted on
different servers, are defined and related to each other. The example below
defines a web application stack hosted on the web_server
“compute” resource, and a database software stack similar to the one shown
earlier in section 6 hosted on the db_server
compute resource.
Example 6 - Basic two-tier application (web
application and database server tiers)
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying a two-tier application servers on two
topology_template:
inputs:
# Admin user name and password
to use with the WordPress application
wp_admin_username:
type: string
wp_admin_password:
type: string
wp_db_name:
type: string
wp_db_user:
type: string
wp_db_password:
type: string
wp_db_port:
type: integer
mysql_root_password:
type: string
mysql_port:
type: integer
context_root:
type: string
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
properties:
context_root: { get_input:
context_root }
admin_user: { get_input:
wp_admin_username }
admin_password: {
get_input: wp_admin_password }
db_host: {
get_attribute: [ db_server, private_address ] }
requirements:
- host: apache
- database_endpoint:
wordpress_db
interfaces:
Standard:
inputs:
db_host: {
get_attribute: [ db_server, private_address ] }
db_port: {
get_property: [ wordpress_db, port ] }
db_name: {
get_property: [ wordpress_db, name ] }
db_user: {
get_property: [ wordpress_db, user ] }
db_password: {
get_property: [ wordpress_db, password ] }
apache:
type:
tosca.nodes.WebServer.Apache
properties:
# omitted here for brevity
requirements:
- host: web_server
web_server:
type: tosca.nodes.Compute
capabilities:
# omitted here for brevity
wordpress_db:
type:
tosca.nodes.Database.MySQL
properties:
name: { get_input:
wp_db_name }
user: { get_input:
wp_db_user }
password: { get_input:
wp_db_password }
port: { get_input:
wp_db_port }
requirements:
- host: mysql
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: {
get_input: mysql_root_password }
port: { get_input:
mysql_port }
requirements:
- host: db_server
db_server:
type: tosca.nodes.Compute
capabilities:
# omitted here for brevity
|
The web application stack
consists of the wordpress [WordPress],
the apache [Apache] and the web_server
node templates. The wordpress node template represents a custom web
application of type tosca.nodes.WebApplication.WordPress which is hosted
on an Apache web server represented by the apache node template. This
hosting relationship is expressed via the host entry in the requirements
section of the wordpress node template. The apache node template,
finally, is hosted on the web_server compute node.
The database stack consists of the wordpress_db, the mysql
and the db_server node templates. The wordpress_db node
represents a custom database of type tosca.nodes.Database.MySQL which is
hosted on a MySQL DBMS represented by the mysql node template. This
node, in turn, is hosted on the db_server compute node.
The wordpress node requires a connection to
the wordpress_db node, since the WordPress application needs a database
to store its data in. This relationship is established through the database_endpoint entry in the requirements
section of the wordpress node template’s declared node type. For
configuring the WordPress web application, information about the database to
connect to is required as input to the configure operation. Therefore,
the input parameters are defined and values for them are retrieved from the
properties and attributes of the wordpress_db node via the get_property
and get_attribute functions. In the
above example, these inputs are defined at the interface-level and would be
available to all operations of the Standard
interface (i.e., the tosca.interfaces.node.lifecycle.Standard
interface) within the wordpress node
template and not just the configure
operation.
In previous examples, the
template author did not have to think about explicit relationship types to be
used to link a requirement of a node to another node of a model, nor did the
template author have to think about special logic to establish those links. For
example, the host requirement
in previous examples just pointed to another node template and based on
metadata in the corresponding node type definition the relationship type to be
established is implicitly given.
In some cases, it might be
necessary to provide special processing logic to be executed when establishing
relationships between nodes at runtime. For example, when connecting the
WordPress application from previous examples to the MySQL database, it might be
desired to apply custom configuration logic in addition to that already
implemented in the application node type. In such a case, it is possible for
the template author to provide a custom script as implementation for an
operation to be executed at runtime as shown in the following example.
Example 7 - Providing a custom relationship script to
establish a connection
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description:
Template for deploying a two-tier application on two servers.
topology_template:
inputs:
#
omitted here for brevity
node_templates:
wordpress:
type: tosca.nodes.WebApplication.WordPress
properties:
# omitted here for brevity
requirements:
- host: apache
- database_endpoint:
node: wordpress_db
relationship: my_custom_database_connection
wordpress_db:
type: tosca.nodes.Database.MySQL
properties:
# omitted here for the brevity
requirements:
- host: mysql
relationship_templates:
my_custom_database_connection:
type: ConnectsTo
interfaces:
Configure:
pre_configure_source: scripts/wp_db_configure.sh
#
other resources not shown for this example ...
|
The node type definition for the wordpress node template is WordPress which declares the complete database_endpoint
requirement definition. This database_endpoint
declaration indicates it must be fulfilled by any node template that provides
an Endpoint.Database Capability Type
using a ConnectsTo relationship. The wordpress_db
node template’s underlying MySQL type
definition indeed provides the Endpoint.Database
Capability type. In this example however, no explicit relationship
template is declared; therefore, TOSCA orchestrators would automatically create
a ConnectsTo relationship to establish the link between the wordpress node and the wordpress_db node at runtime.
The ConnectsTo
relationship (see 5.7.4) also provides a default Configure interface with operations that
optionally get executed when the orchestrator establishes the relationship. In
the above example, the author has provided the custom script wp_db_configure.sh to be executed for the
operation called pre_configure_source. The script file is
assumed to be located relative to the referencing service template such as a
relative directory within the TOSCA Cloud Service Archive (CSAR) packaging
format. This approach allows for conveniently hooking in custom behavior
without having to define a completely new derived relationship type.
In the previous section it was
shown how custom behavior can be injected by specifying scripts inline in the
requirements section of node templates. When the same custom behavior is
required in many templates, it does make sense to define a new relationship
type that encapsulates the custom behavior in a re-usable way instead of
repeating the same reference to a script (or even references to multiple
scripts) in many places.
Such a custom relationship type
can then be used in templates as shown in the following example.
Example 8 - A web application Node Template requiring
a custom database connection type
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for
deploying a two-tier application on two servers.
topology_template:
inputs:
# omitted here for brevity
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
properties:
# omitted here for brevity
requirements:
- host: apache
- database_endpoint:
node: wordpress_db
relationship: my.types.WordpressDbConnection
wordpress_db:
type:
tosca.nodes.Database.MySQL
properties:
# omitted here for the
brevity
requirements:
- host: mysql
# other resources not shown
here ...
|
In the example above, a special relationship type my.types.WordpressDbConnection is
specified for establishing the link between the wordpress node and the wordpress_db
node through the use of the relationship
(keyword) attribute in the database
reference. It is assumed, that this special relationship type provides some
extra behavior (e.g., an operation with a script) in addition to what a generic
“connects to” relationship would provide. The definition of this custom
relationship type is shown in the following section.
The following YAML snippet shows the definition of
the custom relationship type used in the previous section. This type derives
from the base “ConnectsTo” and overrides one operation defined by that base
relationship type. For the pre_configure_source
operation defined in the Configure
interface of the ConnectsTo relationship type, a script implementation is
provided. It is again assumed that the custom configure script is located at a
location relative to the referencing service template, perhaps provided in some
application packaging format (e.g., the TOSCA Cloud Service Archive (CSAR)
format).
Example 9 - Defining a custom relationship type
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Definition of custom
WordpressDbConnection relationship type
relationship_types:
my.types.WordpressDbConnection:
derived_from:
tosca.relationships.ConnectsTo
interfaces:
Configure:
pre_configure_source:
scripts/wp_db_configure.sh
|
In the above example, the Configure interface is the specified alias or
shorthand name for the TOSCA interface type with the full name of tosca.interfaces.relationship.Configure which
is defined in the appendix.
In some cases, it can be
necessary to define a generic dependency between two nodes in a template to
influence orchestration behavior, i.e. to first have one node processed before
another dependent node gets processed. This can be done by using the generic dependency requirement which is defined by
the TOSCA Root Node Type and thus gets
inherited by all other node types in TOSCA (see section 5.9.1).
Example 10 - Simple dependency relationship between
two nodes
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template with a
generic dependency between two nodes.
topology_template:
inputs:
# omitted here for brevity
node_templates:
my_app:
type: my.types.MyApplication
properties:
# omitted here for brevity
requirements:
- dependency: some_service
some_service:
type: some.nodetype.SomeService
properties:
# omitted here for brevity
|
As in previous examples, the relation that one node
depends on another node is expressed in the requirements
section using the built-in requirement named dependency
that exists for all node types in TOSCA. Even if the creator of the MyApplication node type did not define a
specific requirement for SomeService
(similar to the database requirement in
the example in section 2.6), the template author who knows that there is a
timing dependency and can use the generic dependency
requirement to express that constraint using the very same syntax as used for
all other references.
In TOSCA templates, nodes are either:
·
Concrete: meaning that they have a deployment and/or one
or more implementation artifacts that are declared on the “create” operation of
the node’s Standard lifecycle interface, or they are
·
Abstract: where the template describes the node type along
with its required capabilities and properties that must be satisfied.
TOSCA Orchestrators, by default, when finding an abstract
node in TOSCA Service Template during deployment will attempt to “select” a
concrete implementation for the abstract node type that best matches and
fulfills the requirements and property constraints the template author provided
for that abstract node. The concrete implementation of the node could be
provided by another TOSCA Service Template (perhaps located in a catalog or
repository known to the TOSCA Orchestrator) or by an existing resource or
service available within the target Cloud Provider’s platform that the TOSCA Orchestrator
already has knowledge of.
TOSCA supports two methods for template authors to express
requirements for an abstract node within a TOSCA service template.
1. Using
a target node_filter: where a node template can describe a requirement
(relationship) for another node without including it in the topology. Instead,
the node provides a node_filter to describe the
target node type along with its capabilities and property constrains
2. Using
an abstract node template: that describes the abstract node’s type
along with its property constraints and any requirements and capabilities it
also exports. This first method you have already seen in examples from
previous chapters where the Compute node is abstract and selectable by the
TOSCA Orchestrator using the supplied Container and OperatingSystem capabilities property
constraints.
These approaches allow architects and developers to create
TOSCA service templates that are composable and can be reused by allowing flexible
matching of one template’s requirements to another’s capabilities. Examples of
both these approaches are shown below.
Using TOSCA, it is possible to
define only the software components of an application in a template and just
express constrained requirements against the hosting infrastructure. At
deployment time, the provider can then do a late binding and dynamically allocate
or assign the required hosting infrastructure and place software components on
top.
This example shows how a single software component (i.e.,
the mysql node template) can define its host
requirements that the TOSCA Orchestrator and provider will use to select or
allocate an appropriate host Compute
node by using matching criteria provided on a node_filter.
Example
11 - An abstract "host" requirement using a node filter
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template with
requirements against hosting infrastructure.
topology_template:
inputs:
# omitted here for brevity
node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
# omitted here for brevity
requirements:
- host:
node_filter:
capabilities:
# Constraints for
selecting “host” (Container Capability)
- host:
properties:
- num_cpus:
{ in_range: [ 1, 4 ] }
- mem_size:
{ greater_or_equal: 2 GB }
# Constraints for
selecting “os” (OperatingSystem Capability)
- os:
properties:
-
architecture: { equal: x86_64 }
- type:
linux
- distribution: ubuntu
|
In the example above, the mysql component contains a host requirement for a node of type Compute which it inherits from its
parent DBMS node type definition; however, there is no declaration or reference
to any node template of type Compute.
Instead, the mysql node template
augments the abstract “host”
requirement with a node_filter which
contains additional selection criteria (in the form of property constraints
that the provider must use when selecting or allocating a host Compute node.
Some of the constraints shown above narrow down the
boundaries of allowed values for certain properties such as mem_size or num_cpus
for the “host” capability by means of
qualifier functions such as greater_or_equal.
Other constraints, express specific values such as for the architecture or distribution properties of the “os” capability which will require the
provider to find a precise match.
Note that when no qualifier
function is provided for a property (filter), such as for the distribution property, it is interpreted to
mean the equal operator as shown on the
architecture property.
2.9.2
Using an abstract node template to define infrastructure requirements for
software
This previous approach works well if no other
component (i.e., another node template) other than mysql node template wants to reference the
same Compute node the orchestrator
would instantiate. However, perhaps another component wants to also be deployed
on the same host, yet still allow the flexible matching achieved using a
node-filter. The alternative to the above approach is to create an abstract node
template that represents the Compute
node in the topology as follows:
Example
12 - An abstract Compute node template with a node filter
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description:
Template with requirements against hosting infrastructure.
topology_template:
inputs:
# omitted here for brevity
node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
# omitted here for brevity
requirements:
- host: mysql_compute
# Abstract node template (placeholder) to be selected by provider
mysql_compute:
type: Compute
node_filter:
capabilities:
- host:
properties:
num_cpus: { equal: 2 }
mem_size: { greater_or_equal: 2 GB }
- os:
properties:
architecture: { equal: x86_64 }
type: linux
distribution: ubuntu
|
As you can see the resulting mysql_compute node template looks very much
like the “hello world” template as shown in Chapter
2.1 (where the Compute node
template was abstract), but this one also allows the TOSCA orchestrator more
flexibility when “selecting” a host Compute
node by providing flexible constraints for properties like mem_size.
As we proceed, you will see that TOSCA provides many
normative node types like Compute for
commonly found services (e.g., BlockStorage,
WebServer, Network, etc.). When these TOSCA normative
node types are used in your application’s topology they are always assumed to
be “selectable” by TOSCA Orchestrators which work with target infrastructure
providers to find or allocate the best match for them based upon your
application’s requirements and constraints.
In the same way requirements
can be defined on the hosting infrastructure (as shown above) for an
application, it is possible to express requirements against application or
middleware components such as a database that is not defined in the same
template. The provider may then allocate a database by any means, (e.g. using a
database-as-a-service solution).
Example
13 - An abstract database requirement using a node filter
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template with a TOSCA
Orchestrator selectable database requirement using a node_filter.
topology_template:
inputs:
# omitted here for brevity
node_templates:
my_app:
type: my.types.MyApplication
properties:
admin_user: { get_input:
admin_username }
admin_password: {
get_input: admin_password }
db_endpoint_url: {
get_property: [SELF, database_endpoint,
url_path ] }
requirements:
- database_endpoint:
node:
my.types.nodes.MyDatabase
node_filter:
properties:
- db_version: {
greater_or_equal: 5.5 }
|
In the example above, the application my_app requires a database node of type MyDatabase which has a db_version property value of greater_or_equal to the value 5.5.
This example also shows how the get_property intrinsic function can be used
to retrieve the url_path property from
the database node that will be selected by the provider and connected to my_app at runtime due to fulfillment of the database_endpoint requirement. To locate the
property, the get_property’s first argument is set to the keyword SELF which indicates the property is being
referenced from something in the node itself. The second parameter is the name
of the requirement named database_endpoint
which contains the property we are looking for. The last argument is
the name of the property itself (i.e., url_path)
which contains the value we want to retrieve and assign to db_endpoint_url.
The alternative representation,
which includes a node template in the topology for database that is still
selectable by the TOSCA orchestrator for the above example, is as follows:
Example
14 - An abstract database node template
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template with a TOSCA
Orchestrator selectable database using node template.
topology_template:
inputs:
# omitted here for brevity
node_templates:
my_app:
type: my.types.MyApplication
properties:
admin_user: { get_input:
admin_username }
admin_password: {
get_input: admin_password }
db_endpoint_url: {
get_property: [SELF, database_endpoint, url_path ] }
requirements:
- database_endpoint: my_abstract_database
my_abstract_database:
type:
my.types.nodes.MyDatabase
properties:
- db_version: {
greater_or_equal: 5.5 }
|
From an application perspective, it is often not necessary
or desired to dive into platform details, but the platform/runtime for an
application is abstracted. In such cases, the template for an application can
use generic representations of platform components. The details for such
platform components, such as the underlying hosting infrastructure at its
configuration, can then be defined in separate template files that can be used
for substituting the more abstract representations in the application level
template file.
When a topology template is instantiated by a TOSCA
Orchestrator, the orchestrator has to look for realizations of the single node
templates according to the node types specified for each node template. Such
realizations can either be node types that include the appropriate
implementation artifacts and deployment artifacts that can be used by the
orchestrator to bring to life the real-world resource modeled by a node
template. Alternatively, separate topology templates may be annotated as being
suitable for realizing a node template in the top-level topology template.
In the latter case, a TOSCA Orchestrator will use additional
substitution mapping information provided as part of the substituting topology
templates to derive how the substituted part gets “wired” into the overall
deployment, for example, how capabilities of a node template in the top-level
topology template get bound to capabilities of node templates in the
substituting topology template.
Thus, in cases where no “normal” node type implementation is
available, or the node type corresponds to a whole subsystem that cannot be
implemented as a single node, additional topology templates can be used for
filling in more abstract placeholders in top level application templates.
The
following sample defines a web application web_app
connected to a database db. In
this example, the complete hosting stack for the application is defined within
the same topology template: the web application is hosted on a web server web_server, which in turn is installed
(hosted) on a compute node server.
The hosting stack for the
database db, in contrast, is not
defined within the same file but only the database is represented as a node
template of type tosca.nodes.Database.
The underlying hosting stack for the database is defined in a separate template
file, which is shown later in this section. Within the current template, only a
number of properties (user, password, name)
are assigned to the database using hardcoded values in this simple example.
Figure 1:
Using template substitution to implement a database tier
When a node template is to be substituted by another service
template, this has to be indicated to an orchestrator by means of a special “substitutable”
directive. This directive causes, for example, special processing behavior when
validating the left-hand service template in Figure 1. The hosting requirement
of the db node template is not bound to
any capability defined within the service template, which would normally cause
a validation error. When the “substitutable” directive is present, the
orchestrator will however first try to perform substitution of the respective
node template and after that validate if all mandatory requirements of all
nodes in the resulting graph are fulfilled.
Note that in contrast to the use case described in section 2.9.2 (where a database was abstractly referred to in the requirements section of a node and the
database itself was not represented as a node template), the approach shown
here allows for some additional modeling capabilities in cases where this is
required.
For example, if multiple components need to use the same database (or any other
sub-system of the overall service), this can be expressed by means of normal
relations between node templates, whereas such modeling would not be possible
in requirements sections of disjoint
node templates.
Example
15 - Referencing an abstract database node template
|
tosca_definitions_version:
tosca_simple_yaml_1_0
topology_template:
description:
Template of an application connecting to a database.
node_templates:
web_app:
type: tosca.nodes.WebApplication.MyWebApp
requirements:
- host: web_server
- database_endpoint: db
web_server:
type: tosca.nodes.WebServer
requirements:
- host: server
server:
type: tosca.nodes.Compute
# details omitted for brevity
db:
# This node is abstract (no Deployment or Implementation artifacts on create)
# and can be substituted with a topology provided by another template
# that exports a Database type’s capabilities.
type: tosca.nodes.Database
properties:
user: my_db_user
password: secret
name: my_db_name
|
The following sample defines a template for a
database including its complete hosting stack, i.e. the template includes a database node template, a template for the
database management system (dbms) hosting
the database, as well as a computer node server
on which the DBMS is installed.
This service template can be used standalone for deploying
just a database and its hosting stack. In the context of the current use case,
though, this template can also substitute the database node template in the
previous snippet and thus fill in the details of how to deploy the database.
In order to enable such a substitution, an additional metadata
section substitution_mappings is added
to the topology template to tell a TOSCA Orchestrator how exactly the topology
template will fit into the context where it gets used. For example,
requirements or capabilities of the node that gets substituted by the topology
template have to be mapped to requirements or capabilities of internal node
templates for allow for a proper wiring of the resulting overall graph of node
templates.
In short, the substitution_mappings
section provides the following information:
1. It defines
what node templates, i.e. node templates of which type, can be substituted by
the topology template.
2. It defines
how capabilities of the substituted node (or the capabilities defined by the
node type of the substituted node template, respectively) are bound to
capabilities of node templates defined in the topology template.
3. It defines
how requirements of the substituted node (or the requirements defined by the
node type of the substituted node template, respectively) are bound to
requirements of node templates defined in the topology template.
Figure 2: Substitution mappings
The substitution_mappings
section in the sample below denotes that this topology template can be used for
substituting node templates of type tosca.nodes.Database.
It further denotes that the database_endpoint
capability of the substituted node gets fulfilled by the database_endpoint capability of the database node contained in the topology
template.
Example
16 - Using substitution mappings to export a database implementation
|
tosca_definitions_version:
tosca_simple_yaml_1_0
topology_template:
description: Template of a database including its hosting stack.
inputs:
db_user:
type: string
db_password:
type: string
#
other inputs omitted for brevity
substitution_mappings:
node_type: tosca.nodes.Database
capabilities:
database_endpoint: [ database, database_endpoint ]
node_templates:
database:
type: tosca.nodes.Database
properties:
user: { get_input: db_user }
# other properties omitted for brevity
requirements:
- host: dbms
dbms:
type: tosca.nodes.DBMS
# details omitted for brevity
server:
type: tosca.nodes.Compute
# details omitted for brevity
|
Note that the substitution_mappings
section does not define any mappings for requirements of the Database node
type, since all requirements are fulfilled by other nodes templates in the
current topology template. In cases where a requirement of a substituted node
is bound in the top-level service template as well as in the substituting
topology template, a TOSCA Orchestrator should raise a validation error.
Further note that no mappings for properties or attributes
of the substituted node are defined. Instead, the inputs and outputs defined by
the topology template have to match the properties and attributes or the
substituted node. If there are more inputs than the substituted node has
properties, default values must be defined for those inputs, since no values
can be assigned through properties in a substitution case.
A common use case when providing an end-to-end service is to
define a chain of several subsystems that together implement the overall service.
Those subsystems are typically defined as separate service templates to (1)
keep the complexity of the end-to-end service template at a manageable level
and to (2) allow for the re-use of the respective subsystem templates in many
different contexts. The type of subsystems may be specific to the targeted
workload, application domain, or custom use case. For example, a company or a
certain industry might define a subsystem type for company- or industry
specific data processing and then use that subsystem type for various end-user
services. In addition, there might be generic subsystem types like a database
subsystem that are applicable to a wide range of use cases.
Figure 3 shows the chaining of three subsystem types
– a message queuing subsystem, a transaction processing subsystem, and a
databank subsystem – that support, for example, an online booking application.
On the front end, this chain provides a capability of receiving messages for
handling in the message queuing subsystem. The message queuing subsystem in
turn requires a number of receivers, which in the current example are two
transaction processing subsystems. The two instances of the transaction
processing subsystem might be deployed on two different hosting infrastructures
or datacenters for high-availability reasons. The transaction processing
subsystems finally require a database subsystem for accessing and storing
application specific data. The database subsystem in the backend does not
require any further component and is therefore the end of the chain in this
example.
Figure 3:
Chaining of subsystems in a service template
All of the node templates in the service template shown
above are abstract and considered substitutable where each can be treated as
their own subsystem; therefore, when instantiating the overall service, the
orchestrator would realize each substitutable node template using other TOSCA
service templates. These service templates would include more nodes and
relationships that include the details for each subsystem. A simplified version
of a TOSCA service template for the overall service is given in the following
listing.
Example
17 - Declaring a transaction subsystem as a chain of substitutable node
templates
|
tosca_definitions_version:
tosca_simple_yaml_1_0
topology_template:
description: Template of online transaction processing service.
node_templates:
mq:
type: example.QueuingSubsystem
properties:
# properties omitted for brevity
capabilities:
message_queue_endpoint:
# details omitted for brevity
requirements:
- receiver: trans1
- receiver: trans2
trans1:
type: example.TransactionSubsystem
properties:
mq_service_ip: { get_attribute: [ mq, service_ip ] }
receiver_port: 8080
capabilities:
message_receiver:
# details omitted for brevity
requirements:
- database_endpoint: dbsys
trans2:
type: example.TransactionSubsystem
properties:
mq_service_ip: { get_attribute: [ mq, service_ip ] }
receiver_port: 8080
capabilities:
message_receiver:
# details omitted for brevity
requirements:
- database_endpoint: dbsys
dbsys:
type: example.DatabaseSubsystem
properties:
# properties omitted for brevity
capabilities:
database_endpoint:
# details omitted for brevity
|
As can be seen in the example above, the subsystems are
chained to each other by binding requirements of one subsystem node template to
other subsystem node templates that provide the respective capabilities. For
example, the receiver requirement of
the message queuing subsystem node template mq
is bound to transaction processing subsystem node templates trans1 and trans2.
Subsystems can be parameterized by providing
properties. In the listing above, for example, the IP address of the message
queuing server is provided as property mq_service_ip
to the transaction processing subsystems and the desired port for receiving
messages is specified by means of the receiver_port
property.
If attributes of the instantiated subsystems need to
be obtained, this would be possible by using the get_attribute intrinsic function on the
respective subsystem node templates.
The types of subsystems that are required for a certain
end-to-end service are defined as TOSCA node types as shown in the following
example. Node templates of those node types can then be used in the end-to-end
service template to define subsystems to be instantiated and chained for
establishing the end-to-end service.
The realization of the defined node type will be given in
the form of a whole separate service template as outlined in the following
section.
Example
18 - Defining a TransactionSubsystem node type
|
tosca_definitions_version:
tosca_simple_yaml_1_0
node_types:
example.TransactionSubsystem:
properties:
mq_service_ip:
type: string
receiver_port:
type: integer
attributes:
receiver_ip:
type: string
receiver_port:
type: integer
capabilities:
message_receiver: tosca.capabilities.Endpoint
requirements:
- database_endpoint: tosca.capabilities.Endpoint.Database
|
Configuration parameters that would be allowed for
customizing the instantiation of any subsystem are defined as properties of the
node type. In the current example, those are the properties mq_service_ip and receiver_port that had been used in the
end-to-end service template in section 2.11.1.
Observable attributes of the
resulting subsystem instances are defined as attributes of the node type. In
the current case, those are the IP address of the message receiver as well as
the actually allocated port of the message receiver endpoint.
The details of a subsystem, i.e. the software components and
their hosting infrastructure, are defined as node templates and relationships
in a service template. By means of substitution mappings that have been
introduced in section 2.10.2, the service template is annotated to indicate to
an orchestrator that it can be used as realization of a node template of
certain type, as well as how characteristics of the node type are mapped to
internal elements of the service template.
Figure 4: Defining subsystem details in a service
template
Figure 1 illustrates how a transaction processing subsystem
as outlined in the previous section could be defined in a service template. In
this example, it simply consists of a custom application app of type SomeApp
that is hosted on a web server websrv,
which in turn is running on a compute node.
The application named app provides a capability to receive
messages, which is bound to the message_receiver
capability of the substitutable node type. It further requires access to a
database, so the application’s database_endpoint
requirement is mapped to the database_endpoint
requirement of the TransactionSubsystem
node type.
Properties of the TransactionSubsystem node type are used to
customize the instantiation of a subsystem. Those properties can be mapped to
any node template for which the author of the subsystem service template wants
to expose configurability. In the current example, the application app and the
web server middleware websrv get
configured through properties of the TransactionSubsystem
node type. All properties of that node type are defined as inputs of the service template. The input
parameters in turn get mapped to node templates by means of get_input function calls in the respective
sections of the service template.
Similarly, attributes of the whole subsystem can be
obtained from attributes of particular node templates. In the current example,
attributes of the web server and the hosting compute node will be exposed as
subsystem attributes. All exposed attributes that are defined as attributes of
the substitutable TransactionSubsystem
node type are defined as outputs of the subsystem service template.
An outline of the subsystem service
template is shown in the listing below. Note that this service template could
be used for stand-alone deployment of a transaction processing system as well,
i.e. it is not restricted just for use in substitution scenarios. Only the
presence of the substitution_mappings
metadata section in the topology_template
enables the service template for substitution use cases.
Example
19 - Implementation of a TransactionSubsytem node type using substitution
mappings
|
tosca_definitions_version:
tosca_simple_yaml_1_0
topology_template:
description: Template of a database including its hosting stack.
inputs:
mq_service_ip:
type: string
description: IP address of the message queuing server to receive messages
from
receiver_port:
type: string
description: Port to be used for receiving messages
#
other inputs omitted for brevity
substitution_mappings:
node_type: example.TransactionSubsystem
capabilities:
message_receiver: [ app, message_receiver
]
requirements:
database_endpoint: [ app, database ]
node_templates:
app:
type: example.SomeApp
properties:
# properties omitted for brevity
capabilities:
message_receiver:
properties:
service_ip: { get_input: mq_service_ip }
# other properties omitted for brevity
requirements:
- database:
# details omitted for brevity
- host: websrv
websrv:
type: tosca.nodes.WebServer
properties:
# properties omitted for brevity
capabilities:
data_endpoint:
properties:
port_name: { get_input: receiver_port }
# other properties omitted for brevity
requirements:
- host: server
server:
type: tosca.nodes.Compute
# details omitted for brevity
outputs:
receiver_ip:
description: private IP address of the message
receiver application
value: { get_attribute: [ server, private_address
] }
receiver_port:
description: Port of the message receiver
endpoint
value: { get_attribute: [ app, app_endpoint, port
] }
|
2.12 Grouping node templates
In designing applications composed of several interdependent
software components (or nodes) it is often desirable to manage these components
as a named group. This can provide an effective way of associating policies
(e.g., scaling, placement, security or other) that orchestration tools can
apply to all the components of group during deployment or during other
lifecycle stages.
In many realistic scenarios it is desirable to
include scaling capabilities into an application to be able to react on load
variations at runtime. The example below shows the definition of a scaling web
server stack, where a variable number of servers with apache installed on them
can exist, depending on the load on the servers.
Example
20 - Grouping Node Templates for possible policy application
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template for a
scaling web server.
topology_template:
inputs:
# omitted here for brevity
node_templates:
apache:
type:
tosca.nodes.WebServer.Apache
properties:
# Details omitted for
brevity
requirements:
- host: server
server:
type: tosca.nodes.Compute
# details omitted for
brevity
groups:
webserver_group:
type: tosca.groups.Root
members: [ apache, server ]
|
The example first of all uses the concept of
grouping to express which components (node templates) need to be scaled as a
unit – i.e. the compute nodes and the software on-top of each compute node.
This is done by defining the webserver_group
in the groups section of the template
and by adding both the apache node
template and the server node
template as a member to the group.
Furthermore, a scaling policy
is defined for the group to express that the group as a whole (i.e. pairs of server node and the apache component installed on top)
should scale up or down under certain conditions.
In cases where no explicit
binding between software components and their hosting compute resources is
defined in a template, but only requirements are defined as has been shown in
section 2.9, a provider could decide to place software components on the same
host if their hosting requirements match, or to place them onto different
hosts.
It is often desired, though, to
influence placement at deployment time to make sure components get collocation
or anti-collocated. This can be expressed via grouping and policies as shown in
the example below.
Example
21 - Grouping nodes for anti-colocation policy application
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: Template hosting
requirements and placement policy.
topology_template:
inputs:
# omitted here for brevity
node_templates:
wordpress_server:
type: tosca.nodes.WebServer
properties:
# omitted here for brevity
requirements:
- host:
# Find a Compute node
that fulfills these additional filter reqs.
node_filter:
capabilities:
- host:
properties:
- mem_size:
{ greater_or_equal: 512 MB }
- disk_size:
{ greater_or_equal: 2 GB }
- os:
properties:
-
architecture: x86_64
- type:
linux
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
# omitted here for brevity
requirements:
- host:
node:
tosca.nodes.Compute
node_filter:
capabilities:
- host:
properties:
- disk_size:
{ greater_or_equal: 1 GB }
- os:
properties:
-
architecture: x86_64
- type:
linux
groups:
my_co_location_group:
type: tosca.groups.Root
members: [ wordpress_server,
mysql ]
policies:
- my_anti_collocation_policy:
type:
my.policies.anticolocateion
targets: [
my_co_location_group ]
# For this example,
specific policy definitions are considered
# domain specific and are
not included here
|
In the example above, both software components wordpress_server and mysql have similar hosting
requirements. Therefore, a provider could decide to put both on the same server
as long as both their respective requirements can be fulfilled. By defining a
group of the two components and attaching an anti-collocation policy to the group
it can be made sure, though, that both components are put onto different hosts
at deployment time.
The YAML 1.2 specification allows for defining of aliases, which allow
for authoring a block of YAML (or node) once and indicating it is an “anchor”
and then referencing it elsewhere in the same document as an “alias”.
Effectively, YAML parsers treat this as a “macro” and copy the anchor block’s
code to wherever it is referenced. Use of this feature is especially helpful
when authoring TOSCA Service Templates where similar definitions and property
settings may be repeated multiple times when describing a multi-tier
application.
For example, an application that has a web server and
database (i.e., a two-tier application) may be described using two Compute nodes (one to host the web server and
another to host the database). The author may want both Compute nodes to be
instantiated with similar properties such as operating system, distribution,
version, etc.
To accomplish this, the author would describe the
reusable properties using a named anchor in the “dsl_definitions” section of the TOSCA Service
Template and reference the anchor name as an alias in any Compute node templates where these properties
may need to be reused. For example:
Example 22
- Using YAML anchors in TOSCA templates
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile that just
defines a YAML macro for commonly reused Compute
properties.
dsl_definitions:
my_compute_node_props:
&my_compute_node_props
disk_size: 10 GB
num_cpus: 1
mem_size: 2 GB
topology_template:
node_templates:
my_server:
type: Compute
capabilities:
- host:
properties:
*my_compute_node_props
my_database:
type: Compute
capabilities:
- host:
properties:
*my_compute_node_props
|
It is possible for type and template authors to declare
input variables within an inputs block
on interfaces to nodes or relationships in order to pass along information
needed by their operations (scripts). These declarations can be scoped such as
to make these variable values available to all operations on a node or
relationships interfaces or to individual operations. TOSCA orchestrators will
make these values available as environment variables within the execution
environments in which the scripts associated with lifecycle operations are run.
2.14.1 Example: declaring
input variables for all operations on a single interface
|
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
requirements:
...
- database_endpoint:
mysql_database
interfaces:
Standard:
inputs:
wp_db_port: {
get_property: [ SELF, database_endpoint, port ] }
|
|
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
requirements:
...
- database_endpoint:
mysql_database
interfaces:
Standard:
create:
wordpress_install.sh
configure:
implementation:
wordpress_configure.sh
inputs:
wp_db_port: {
get_property: [ SELF, database_endpoint, port ] }
|
In the case where an input variable name is defined
at more than one scope within the same interfaces section of a node or template
definition, the lowest (or innermost) scoped declaration would override those
declared at higher (or more outer) levels of the definition.
|
node_templates:
frontend:
type: MyTypes.SomeNodeType
attributes:
url: { get_operation_output: [ SELF,
Standard, create, generated_url ] }
interfaces:
Standard:
create:
implementation:
scripts/frontend/create.sh
|
In this example, the Standard create operation exposes /
exports an environment variable named “generated_url”
attribute which will be assigned to the WordPress node’s url attribute.
|
node_templates:
frontend:
type: MyTypes.SomeNodeType
interfaces:
Standard:
create:
implementation:
scripts/frontend/create.sh
configure:
implementation:
scripts/frontend/configure.sh
inputs:
data_dir: { get_operation_output: [ SELF, Standard, create, data_dir ] }
|
In this example, the Standard lifecycle’s create operation exposes / exports an
environment variable named “data_dir”
which will be passed as an input to the Standard
lifecycle’s configure operation.
A TOSCA service template contains a topology template,
which models the components of an application, their relationships and
dependencies (a.k.a., a topology model) that get interpreted and instantiated
by TOSCA Orchestrators. The actual node and relationship instances that are
created represent a set of resources distinct from the template itself, called
a topology instance (model). The direction of this specification is to
provide access to the instances of these resources for management and
operational control by external administrators. This model can also be
accessed by an orchestration engine during deployment – i.e. during the actual
process of instantiating the template in an incremental fashion, That is, the
orchestrator can choose the order of resources to instantiate (i.e.,
establishing a partial set of node and relationship instances) and have the
ability, as they are being created, to access them in order to facilitate
instantiating the remaining resources of the complete topology template.
Most entity types in TOSCA (e.g., Node, Relationship,
Requirement and Capability Types) have property
definitions, which allow template authors to set the values for as inputs
when these entities are instantiated by an orchestrator. These property values
are considered to reflect the desired state of the entity by the author. Once
instantiated, the actual values for these properties on the realized
(instantiated) entity are obtainable via attributes on the entity with the same
name as the corresponding property.
In other words, TOSCA orchestrators will
automatically reflect (i.e., make available) any property defined on an entity
making it available as an attribute of the entity with the same name as the
property.
Use of this feature is shown in the example below where a
source node named my_client, of type ClientNode, requires a connection to another
node named my_server of type ServerNode. As you can see, the ServerNode type defines a property named notification_port which defines a dedicated
port number which instances of my_client
may use to post asynchronous notifications to it during runtime. In this case,
the TOSCA Simple Profile assures that the notification_port
property is implicitly reflected as an attribute in the my_server node (also with the name notification_port) when its node template is
instantiated.
Example 23
- Properties reflected as attributes
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile that shows
how the (notification_port) property is reflected as an attribute and can be
referenced elsewhere.
node_types:
ServerNode:
derived_from: SoftwareComponent
properties:
notification_port:
type: integer
capabilities:
# omitted here for brevity
ClientNode:
derived_from: SoftwareComponent
properties:
# omitted here for brevity
requirements:
- server:
capability: Endpoint
node: ServerNode
relationship: ConnectsTo
topology_template:
node_templates:
my_server:
type: ServerNode
properties:
notification_port: 8000
my_client:
type: ClientNode
requirements:
- server:
node: my_server
relationship: my_connection
relationship_templates:
my_connection:
type: ConnectsTo
interfaces:
Configure:
inputs:
targ_notify_port: { get_attribute: [ TARGET, notification_port ] }
# other operation definitions omitted here for brevity
|
Specifically, the above example shows that the ClientNode type needs the notification_port value anytime a node of ServerType is connected to it using the ConnectsTo relationship in order to make it
available to its Configure operations
(scripts). It does this by using the get_attribute
function to retrieve the notification_port
attribute from the TARGET node of the ConnectsTo relationship (which is a node of
type ServerNode) and assigning it to an
environment variable named targ_notify_port.
It should be noted that the actual port value of the notification_port attribute may or may not be
the value 8000 as requested on the
property; therefore, any node that is dependent on knowing its actual “runtime”
value would use the get_attribute
function instead of the get_property
function.
3
TOSCA Simple Profile definitions in YAML
Except for the examples, this section is normative
and describes all of the YAML grammar, definitions and block structure for all
keys and mappings that are defined for the TOSCA Version 1.0 Simple Profile
specification that are needed to describe a TOSCA Service Template (in YAML).
The following TOSCA Namespace URI alias and TOSCA
Namespace Alias are reserved values which SHALL be used when identifying the
TOSCA Simple Profile version 1.0 specification.
The following TOSCA Namespace prefix is a reserved
value and SHALL be used to reference the default TOSCA Namespace URI as
declared in TOSCA Service Templates.
|
Namespace Prefix
|
Specification Description
|
|
tosca
|
The reserved TOSCA Simple Profile Specification prefix
that can be associated with the default TOSCA Namespace URI
|
In the TOSCA Simple Profile, TOSCA Service Templates
MUST always have, as the first line of YAML, the keyword “tosca_definitions_version” with an associated
TOSCA Namespace Alias value. This single line accomplishes the following:
1. Establishes
the TOSCA Simple Profile Specification version whose grammar MUST be used to
parse and interpret the contents for the remainder of the TOSCA Service
Template.
2. Establishes
the default TOSCA Namespace URI and Namespace Prefix for all types found in the
document that are not explicitly namespaced.
3. Automatically
imports (without the use of an explicit import statement) the normative type
definitions (e.g., Node, Relationship, Capability, Artifact, etc.) that are
associated with the TOSCA Simple Profile Specification the TOSCA Namespace
Alias value identifies.
4. Associates
the TOSCA Namespace URI and Namespace Prefix to the automatically imported
TOSCA type definitions.
TOSCA Simple Profiles allows template authors to declare
their own types and templates and assign them simple names with no apparent
namespaces. Since TOSCA Service Templates can import other service templates
to introduce new types and topologies of templates that can be used to provide
concrete implementations (or substitute) for abstract nodes. Rules are needed
so that TOSCA Orchestrators know how to avoid collisions and apply their own
namespaces when import and nesting occur.
3.1.3.1 Additional Requirements
·
Since TOSCA Service Templates can import (or substitute in) other
Service Templates, TOSCA Orchestrators and tooling will encounter the “tosca_definitions_version” statement for each
imported template. In these cases, the following additional requirements
apply:
o
Imported type definitions with the same Namespace URI, local name
and version SHALL be equivalent.
o
If different values of the “tosca_definitions_version”
are encountered, their corresponding type definitions MUST be uniquely
identifiable using their corresponding Namespace URI using a different
Namespace prefix.
·
Duplicate local names (i.e., within the same Service Template
SHALL be considered an error. These include, but are not limited to duplicate
names found for the following definitions:
o
Repositories (repositories)
o
Data Types (data_types)
o
Node Types (node_types)
o
Relationship Types (relationship_types)
o
Capability Types (capability_types)
o
Artifact Types (artifact_types)
o
Interface Types (interface_types)
·
Duplicate Template names within a Service Template’s Topology
Template SHALL be considered an error. These include, but are not limited to
duplicate names found for the following template types:
o
Node Templates (node_templates)
o
Relationship Templates (relationship_templates)
o
Inputs (inputs)
o
Outputs (outputs)
o
Groups (groups)
·
Duplicate names for the following keynames within Types or
Templates SHALL be considered an error. These include, but are not limited to
duplicate names found for the following keynames:
o
Properties (properties)
o
Attributes (attributes)
o
Artifacts (artifacts)
o
Requirements (requirements)
o
Capabilities (capabilities)
o
Interfaces (interfaces)
3.2
Parameter and property types
This clause describes the primitive types that are used for
declaring normative properties, parameters and grammar elements throughout this
specification.
Many of the types we use in this profile are
built-in types from the YAML
1.2 specification (i.e., those identified by the “tag:yaml.org,2002”
version tag) [YAML-1.2].
The following table declares the valid YAML type
URIs and aliases that SHALL be used when possible when defining parameters or
properties within TOSCA Service Templates using this specification:
3.2.1.1 Notes
·
The “string” type is the default type when not specified on a
parameter or property declaration.
·
While YAML supports further type aliases, such as “str” for
“string”, the TOSCA Simple Profile specification promotes the fully expressed
alias name for clarity.
TOSCA supports the concept of “reuse” of type
definitions, as well as template definitions which could be version and change
over time. It is important to provide a reliable, normative means to represent
a version string which enables the comparison and management of types and
templates over time. Therefore, the TOSCA TC intends to provide a normative
version type (string) for this purpose in future Working Drafts of this
specification.
|
Shorthand Name
|
version
|
|
Type Qualified Name
|
tosca:version
|
3.2.2.1 Grammar
TOSCA version strings have the following grammar:
|
<major_version>.<minor_version>[.<fix_version>[.<qualifier>[-<build_version]
] ]
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
major_version: is a
required integer value greater than or equal to 0 (zero)
·
minor_version: is a
required integer value greater than or equal to 0 (zero).
·
fix_version: is an
optional integer value greater than or equal to 0 (zero).
·
qualifier: is an optional
string that indicates a named, pre-release version of the associated code that
has been derived from the version of the code identified by the combination major_version, minor_version and fix_version numbers.
·
build_version: is an
optional integer value greater than or equal to 0 (zero) that can be used to
further qualify different build versions of the code that has the same qualifer_string.
3.2.2.2 Version Comparison
·
When comparing TOSCA versions, all component versions (i.e., major,
minor and fix) are compared in sequence from left to right.
·
TOSCA versions that include the optional qualifier are considered
older than those without a qualifier.
·
TOSCA versions with the same major, minor, and fix versions and
have the same qualifier string, but with different build versions can be
compared based upon the build version.
·
Qualifier strings are considered domain-specific. Therefore,
this specification makes no recommendation on how to compare TOSCA versions
with the same major, minor and fix versions, but with different qualifiers
strings and simply considers them different named branches derived from the
same code.
3.2.2.3 Examples
Examples of valid TOSCA version strings:
|
# basic version strings
6.1
2.0.1
# version string with optional
qualifier
3.1.0.beta
# version string with optional
qualifier and build version
1.0.0.alpha-10
|
3.2.2.4 Notes
·
[Maven-Version] The TOSCA
version type is compatible with the Apache Maven versioning policy.
3.2.2.5 Additional Requirements
·
A version value of zero (i.e., ‘0’, ‘0.0’, or ‘0.0.0’) SHALL
indicate there no version provided.
·
A version value of zero used with any qualifiers SHALL NOT be
valid.
The range type can be used to define numeric ranges
with a lower and upper boundary. For example, this allows for specifying a
range of ports to be opened in a firewall.
|
Shorthand Name
|
range
|
|
Type Qualified Name
|
tosca:range
|
3.2.3.1 Grammar
TOSCA range values have the following grammar:
|
[<lower_bound>,
<upper_bound>]
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
lower_bound: is a
required integer value that denotes the lower boundary of the range.
·
upper_bound: is a
required integer value that denotes the upper boundary of the range. This value
MUST be greater than lower_bound.
3.2.3.2 Keywords
The following Keywords may be used in the TOSCA
range type:
|
Keyword
|
Applicable Types
|
Description
|
|
UNBOUNDED
|
scalar
|
Used to represent an unbounded upper bounds (positive)
value in a set for a scalar type.
|
3.2.3.3 Examples
Example of a node template property with a range
value:
|
# numeric range between 1 and 100
a_range_property: [ 1, 100 ]
# a property that has allows any
number 0 or greater
num_connections: [ 0, UNBOUNDED ]
|
The list type allows for specifying multiple values for a
parameter of property. For example, if an application allows for being
configured to listen on multiple ports, a list of ports could be configured
using the list data type.
Note that entries in a list for one property or
parameter must be of the same type. The type (for simple entries) or schema
(for complex entries) is defined by the entry_schema
attribute of the respective property
definition, attribute definitions,
or input or output parameter definitions.
|
Shorthand Name
|
list
|
|
Type Qualified Name
|
tosca:list
|
3.2.4.1 Grammar
TOSCA lists are essentially normal YAML lists with
the following grammars:
3.2.4.1.1 Square bracket notation
|
[ <list_entry_1>,
<list_entry_2>, ... ]
|
3.2.4.1.2 Bulleted (sequenced) list notation
|
- <list_entry_1>
- ...
- <list_entry_n>
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
<list_entry_*>:
represents one entry of the list.
3.2.4.2 Declaration Examples
3.2.4.2.1 List declaration using a simple type
The following example shows a list declaration with
an entry schema based upon a simple integer type (which has additional
constraints):
|
<some_entity>:
...
properties:
listen_ports:
type: list
entry_schema:
description: listen port
entry (simple integer type)
type: integer
constraints:
- max_length: 128
|
3.2.4.2.2 List declaration using a complex type
The following example shows a list declaration with
an entry schema based upon a complex type:
|
<some_entity>:
...
properties:
products:
type: list
entry_schema:
description: Product
information entry (complex type) defined elsewhere
type: ProductInfo
|
3.2.4.3 Definition Examples
These examples show two notation options for defining lists:
·
A single-line option which is useful for only short lists with
simple entries.
·
A multi-line option where each list entry is on a separate line;
this option is typically useful or more readable if there is a large number of
entries, or if the entries are complex.
3.2.4.3.1 Square bracket notation
|
listen_ports: [ 80, 8080 ]
|
3.2.4.3.2 Bulleted list notation
|
listen_ports:
- 80
- 8080
|
The map type allows for specifying multiple values for a
parameter of property as a map. In contrast to the list type, where each entry
can only be addressed by its index in the list, entries in a map are named
elements that can be addressed by their keys.
Note that entries in a map for one property or
parameter must be of the same type. The type (for simple entries) or schema (for
complex entries) is defined by the entry_schema
attribute of the respective property
definition, attribute definition,
or input or output parameter definition.
|
Shorthand Name
|
map
|
|
Type Qualified Name
|
tosca:map
|
3.2.5.1 Grammar
TOSCA maps are normal YAML dictionaries with
following grammar:
3.2.5.1.1 Single-line grammar
|
{ <entry_key_1>:
<entry_value_1>, ..., <entry_key_n>: <entry_value_n> }
...
<entry_key_n>:
<entry_value_n>
|
3.2.5.1.2 Multi-line grammar
|
<entry_key_1>:
<entry_value_1>
...
<entry_key_n>:
<entry_value_n>
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
entry_key_*: is the
required key for an entry in the map
·
entry_value_*: is the
value of the respective entry in the map
3.2.5.2 Declaration Examples
3.2.5.2.1 Map declaration using a simple type
The following example shows a map with an entry
schema definition based upon an existing string type (which has additional
constraints):
|
<some_entity>:
...
properties:
emails:
type: map
entry_schema:
description: basic email
address
type: string
constraints:
- max_length: 128
|
3.2.5.2.2 Map declaration using a complex type
The following example shows a map with an entry
schema definition for contact information:
|
<some_entity>:
...
properties:
contacts:
type: map
entry_schema:
description: simple
contact information
type: ContactInfo
|
3.2.5.3 Definition Examples
These examples show two notation options for
defining maps:
·
A single-line option which is useful for only short maps with
simple entries.
·
A multi-line option where each map entry is on a separate line;
this option is typically useful or more readable if there is a large number of
entries, or if the entries are complex.
3.2.5.3.1 Single-line notation
|
# notation option for shorter maps
user_name_to_id_map: { user1:
1001, user2: 1002 }
|
3.2.5.3.2 Multi-line notation
|
# notation for longer maps
user_name_to_id_map:
user1: 1001
user2: 1002
|
The scalar-unit type can be used to define scalar values
along with a unit from the list of recognized units provided below.
3.2.6.1 Grammar
TOSCA scalar-unit typed values have the following
grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
scalar: is a required
scalar value.
·
unit: is a required unit
value. The unit value MUST be type-compatible with the scalar.
3.2.6.2 Additional requirements
·
Whitespace: any number of spaces (including zero or
none) SHALL be allowed between the scalar
value and the unit value.
·
It SHALL be considered an error if either the scalar or
unit portion is missing on a property or attribute declaration derived from any
scalar-unit type.
·
When performing constraint clause evaluation on values of the
scalar-unit type, both the scalar value portion and unit value portion SHALL
be compared together (i.e., both are treated as a single value). For example,
if we have a property called storage_size.
which is of type scalar-unit, a valid range constraint would appear as follows:
o storage_size: in_range [ 4 GB, 20 GB ]
where storage_size’s range would be evaluated using
both the numeric and unit values (combined together), in this case ‘4 GB’ and
’20 GB’.
3.2.6.3 Concrete Types
|
Shorthand Names
|
scalar-unit.size, scalar-unit.size
|
|
Type Qualified Names
|
tosca:scalar-unit.size, tosca:scalar-unit.time
|
The scalar-unit type grammar is abstract and has two
recognized concrete types in TOSCA:
·
scalar-unit.size – used to define properties that have
scalar values measured in size units.
·
scalar-unit.time – used to define properties that have
scalar values measured in size units.
·
scalar-unit.frequency – used to define properties that
have scalar values measured in units per second.
These types and their allowed unit values are
defined below.
3.2.6.4.1 Recognized Units
|
Unit
|
Usage
|
Description
|
|
B
|
size
|
byte
|
|
kB
|
size
|
kilobyte (1000 bytes)
|
|
KiB
|
size
|
kibibytes (1024 bytes)
|
|
MB
|
size
|
megabyte (1000000 bytes)
|
|
MiB
|
size
|
mebibyte (1048576 bytes)
|
|
GB
|
size
|
gigabyte (1000000000 bytes)
|
|
GiB
|
size
|
gibibytes (1073741824 bytes)
|
|
TB
|
size
|
terabyte (1000000000000
bytes)
|
|
TiB
|
size
|
tebibyte (1099511627776
bytes)
|
3.2.6.4.2 Examples
|
# Storage size in Gigabytes
properties:
storage_size: 10 GB
|
3.2.6.4.3 Notes
·
The unit values recognized by TOSCA Simple Profile for size-type
units are based upon a subset of those defined by GNU at http://www.gnu.org/software/parted/manual/html_node/unit.html,
which is a non-normative reference to this specification.
·
TOSCA treats these unit values as case-insensitive (e.g., a value
of ‘kB’, ‘KB’ or ‘kb’ would be equivalent), but it is considered best practice
to use the case of these units as prescribed by GNU.
·
Some Cloud providers may not support byte-level granularity for
storage size allocations. In those cases, these values could be treated as
desired sizes and actual allocations would be based upon individual provider
capabilities.
3.2.6.5
scalar-unit.time
3.2.6.5.1 Recognized Units
|
Unit
|
Usage
|
Description
|
|
d
|
time
|
days
|
|
h
|
time
|
hours
|
|
m
|
time
|
minutes
|
|
s
|
time
|
seconds
|
|
ms
|
time
|
milliseconds
|
|
us
|
time
|
microseconds
|
|
ns
|
time
|
nanoseconds
|
3.2.6.5.2 Examples
|
# Response time in milliseconds
properties:
respone_time: 10 ms
|
·
The unit values recognized by TOSCA Simple Profile for time-type
units are based upon a subset of those defined by International System of Units
whose recognized abbreviations are defined within the following reference:
o http://www.ewh.ieee.org/soc/ias/pub-dept/abbreviation.pdf
o
This document is a non-normative reference to this specification
and intended for publications or grammars enabled for Latin characters which
are not accessible in typical programming languages
3.2.6.6.1 Recognized Units
|
Unit
|
Usage
|
Description
|
|
Hz
|
frequency
|
Hertz, or Hz. equals one cycle per second.
|
|
kHz
|
frequency
|
Kilohertz, or kHz, equals to 1,000 Hertz
|
|
MHz
|
frequency
|
Megahertz, or MHz, equals to 1,000,000 Hertz or 1,000 kHz
|
|
GHz
|
frequency
|
Gigahertz, or GHz, equals to 1,000,000,000 Hertz, or
1,000,000 kHz, or 1,000 MHz.
|
3.2.6.6.2 Examples
|
# Processor raw clock rate
properties:
clock_rate: 2.4 GHz
|
3.2.6.6.3 Notes
·
The value for Hertz (Hz) is the International Standard Unit (ISU)
as described by the Bureau International des Poids et Mesures (BIPM) in the “SI Brochure: The International System of Units (SI) [8th edition,
2006; updated in 2014]”, http://www.bipm.org/en/publications/si-brochure/
As components (i.e., nodes) of TOSCA applications are
deployed, instantiated and orchestrated over their lifecycle using normative
lifecycle operations (see section 5.8 for normative lifecycle definitions) it
is important define normative values for communicating the states of these
components normatively between orchestration and workflow engines and any
managers of these applications.
The following table provides the list of recognized
node states for TOSCA Simple Profile that would be set by the orchestrator to
describe a node instance’s state:
|
Node State
|
|
Value
|
Transitional
|
Description
|
|
initial
|
no
|
Node is not yet created.
Node only exists as a template definition.
|
|
creating
|
yes
|
Node is transitioning from initial state
to created state.
|
|
created
|
no
|
Node software has been
installed.
|
|
configuring
|
yes
|
Node is transitioning from created state
to configured state.
|
|
configured
|
no
|
Node has been configured
prior to being started.
|
|
starting
|
yes
|
Node is transitioning from configured
state to started state.
|
|
started
|
no
|
Node is started.
|
|
stopping
|
yes
|
Node is transitioning from
its current state to a configured state.
|
|
deleting
|
yes
|
Node is transitioning from
its current state to one where it is deleted and its state is no longer
tracked by the instance model.
|
|
error
|
no
|
Node is in an error state.
|
Similar to the Node States described in the previous
section, Relationships have state relative to their (normative) lifecycle
operations.
The following table provides the list of recognized
relationship states for TOSCA Simple Profile that would be set by the
orchestrator to describe a node instance’s state:
|
Node State
|
|
Value
|
Transitional
|
Description
|
|
initial
|
no
|
Relationship is not yet
created. Relationship only exists as a template definition.
|
3.3.2.1 Notes
·
Additional states may be defined in future versions of the TOSCA
Simple Profile in YAML specification.
There are currently no directive values defined for
this version of the TOSCA Simple Profile.
The following are recognized values that may be used
as aliases to reference types of networks within an application model without
knowing their actual name (or identifier) which may be assigned by the
underlying Cloud platform at runtime.
|
Alias value
|
Description
|
|
PRIVATE
|
An alias used to reference
the first private network within a property or attribute of a Node or
Capability which would be assigned to them by the underlying platform at
runtime.
A private network contains
IP addresses and ports typically used to listen for incoming traffic to an
application or service from the Intranet and not accessible to the public
internet.
|
|
PUBLIC
|
An alias used to reference
the first public network within a property or attribute of a Node or
Capability which would be assigned to them by the underlying platform at
runtime.
A public network contains IP
addresses and ports typically used to listen for incoming traffic to an
application or service from the Internet.
|
3.3.4.1 Usage
These aliases would be used in the tosca.capabilities.Endpoint Capability type
(and types derived from it) within the network_name
field for template authors to use to indicate the type of network the Endpoint
is supposed to be assigned an IP address from.
This section defines all modelable entities that comprise
the TOSCA Version 1.0 Simple Profile specification along with their keynames,
grammar and requirements.
The TOSCA metamodel includes complex types (e.g., Node
Types, Relationship Types, Capability Types, Data Types, etc.) each of which
include their own list of reserved keynames that are sometimes marked as required.
These types may be used to derive other types. These derived types (e.g.,
child types) do not have to provide required keynames as long as they have been
specified in the type they have been derived from (i.e., their parent type).
This optional element provides a means include single or
multiline descriptions within a TOSCA Simple Profile template as a scalar
string value.
3.5.1.1 Keyname
The following keyname is used to provide a
description within the TOSCA Simple Profile specification:
3.5.1.2 Grammar
Description definitions have the following grammar:
3.5.1.3 Examples
Simple descriptions are treated as a single literal
that includes the entire contents of the line that immediately follows the description key:
|
description: This is an example of a single line description (no
folding).
|
The YAML “folded” style may also be used for
multi-line descriptions which “folds” line breaks as space characters.
|
description: >
This is an example of a
multi-line description using YAML. It permits for line
breaks for easier readability...
if needed. However, (multiple)
line breaks are folded into a single space
character when processed into a
single string value.
|
3.5.1.4 Notes
- Use of “folded” style is discouraged for the YAML string type
apart from when used with the description
keyname.
3.5.2 Constraint
clause
A constraint clause defines an operation along with one or
more compatible values that can be used to define a constraint on a property or
parameter’s allowed values when it is defined in a TOSCA Service Template or
one of its entities.
The following is the list of recognized operators
(keynames) when defining constraint clauses:
|
Operator
|
Type
|
Value Type
|
Description
|
|
equal
|
scalar
|
any
|
Constrains a property or parameter to a value equal to
(‘=’) the value declared.
|
|
greater_than
|
scalar
|
comparable
|
Constrains a property or parameter to a value greater than
(‘>’) the value declared.
|
|
greater_or_equal
|
scalar
|
comparable
|
Constrains a property or parameter to a value greater than
or equal to (‘>=’) the value declared.
|
|
less_than
|
scalar
|
comparable
|
Constrains a property or parameter to a value less than
(‘<’) the value declared.
|
|
less_or_equal
|
scalar
|
comparable
|
Constrains a property or parameter to a value less than or
equal to (‘<=’) the value declared.
|
|
in_range
|
dual scalar
|
comparable, range
|
Constrains a property or parameter to a value in range of
(inclusive) the two values declared.
Note: subclasses or templates of types that declare a
property with the in_range constraint MAY only further restrict the range
specified by the parent type.
|
|
valid_values
|
list
|
any
|
Constrains a property or parameter to a value that is in
the list of declared values.
|
|
length
|
scalar
|
string, list, map
|
Constrains the property or parameter to a value of a given
length.
|
|
min_length
|
scalar
|
string, list, map
|
Constrains the property or parameter to a value to a
minimum length.
|
|
max_length
|
scalar
|
string, list, map
|
Constrains the property or parameter to a value to a
maximum length.
|
|
pattern
|
regex
|
string
|
Constrains the property or parameter to a value that is
allowed by the provided regular expression.
Note: Future drafts of this specification will detail the use of
regular expressions and reference an appropriate standardized grammar.
|
In the Value Type column above, an entry of
“comparable” includes integer, float, timestamp,
string, version,
and scalar-unit types while an entry of “any”
refers to any type allowed in the TOSCA simple profile in YAML.
3.5.2.2 Additional Requirements
·
If no operator is present for a simple scalar-value on a
constraint clause, it SHALL be interpreted as being equivalent to having
the “equal” operator provided; however,
the “equal” operator may be used for
clarity when expressing a constraint clause.
·
The “length” operator SHALL
be interpreted mean “size” for set types (i.e., list, map, etc.).
- Values provided by the operands (i.e., values and scalar values) SHALL
be type-compatible with their associated operations.
- Future drafts of this specification will detail the use of
regular expressions and reference an appropriate standardized grammar.
3.5.2.3 Grammar
Constraint clauses have one of the following
grammars:
|
# Scalar grammar
<operator>:
<scalar_value>
# Dual scalar grammar
<operator>: [
<scalar_value_1>, <scalar_value_2> ]
# List grammar
<operator> [
<value_1>, <value_2>, ..., <value_n> ]
# Regular expression (regex)
grammar
pattern:
<regular_expression_value>
|
In the above grammar, the
pseudo values that appear in angle brackets have the following meaning:
·
operator: represents a
required operator from the specified list shown above (see section 3.5.2.1 “Operator keynames”).
·
scalar_value, scalar_value_*:
represents a required scalar (or atomic quantity) that can hold only one value
at a time. This will be a value of a primitive type, such as an integer or
string that is allowed by this specification.
·
value_*: represents a
required value of the operator that is not limited to scalars.
·
reqular_expression_value:
represents a regular expression (string) value.
3.5.2.4 Examples
Constraint clauses used on parameter or property
definitions:
|
# equal
equal: 2
# greater_than
greater_than: 1
# greater_or_equal
greater_or_equal: 2
# less_than
less_than: 5
# less_or_equal
less_or_equal: 4
# in_range
in_range: [ 1, 4 ]
# valid_values
valid_values: [ 1, 2, 4 ]
# specific length (in characters)
length: 32
# min_length (in characters)
min_length: 8
# max_length (in characters)
max_length: 64
|
A property filter definition defines criteria, using
constraint clauses, for selection of a TOSCA entity based upon it property
values.
3.5.3.1 Grammar
Property filter definitions have one of the
following grammars:
3.5.3.1.1 Short notation:
The following single-line grammar may be used when
only a single constraint is needed on a property:
3.5.3.1.2 Extended notation:
The following multi-line grammar may be used when
multiple constraints are needed on a property:
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
property_name: represents
the name of property that would be used to select a property definition with
the same name (property_name) on a
TOSCA entity (e.g., a Node Type, Node Template, Capability Type, etc.).
·
property_constraint_clause_*:
represents constraint clause(s) that would be used to filter entities based
upon the named property’s value(s).
3.5.3.2 Additional Requirements
·
Property constraint clauses must be type compatible with the
property definitions (of the same name) as defined on the target TOSCA entity
that the clause would be applied against.
A node filter definition defines criteria for selection of a
TOSCA Node Template based upon the template’s property values, capabilities and
capability properties.
3.5.4.1 Keynames
The following is the list of recognized keynames for
a TOSCA node filter definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
properties
|
no
|
list of
property filter definition
|
An optional sequenced list of
property filters that would be used to select (filter) matching TOSCA
entities (e.g., Node Template, Node Type, Capability Types, etc.) based upon
their property definitions’ values.
|
|
capabilities
|
no
|
list of capability names or capability type names
|
An optional sequenced list of
capability names or types that would be used to select (filter) matching
TOSCA entities based upon their existence.
|
3.5.4.2 Additional filtering on named Capability properties
Capabilities used as filters often have their own
sets of properties which also can be used to construct a filter.
|
Keyname
|
Required
|
Type
|
Description
|
|
<capability
name_or_type>
name>:
properties
|
no
|
list of
property filter definitions
|
An optional sequenced list of
property filters that would be used to select (filter) matching TOSCA
entities (e.g., Node Template, Node Type, Capability Types, etc.) based upon
their capabilities’ property definitions’ values.
|
3.5.4.3 Grammar
Node filter definitions have following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
property_filter_def_*: represents
a property filter definition that would be used to select (filter) matching
TOSCA entities (e.g., Node Template, Node Type, Capability Types, etc.) based
upon their property definitions’ values.
·
capability_name_or_type_*:
represents the type or name of a capability that would be used to select
(filter) matching TOSCA entities based upon their existence.
·
cap_*_property_def_*:
represents a property filter definition that would be used to select (filter)
matching TOSCA entities (e.g., Node Template, Node Type, Capability Types,
etc.) based upon their capabilities’ property definitions’ values.
3.5.4.4 Additional requirements
·
TOSCA orchestrators SHALL search for matching capabilities
listed on a target filter by assuming the capability name is first a symbolic
name and secondly it is a type name (in order to avoid namespace collisions).
3.5.4.5 Example
The following example is a filter that would be used to
select a TOSCA Compute node based upon
the values of its defined capabilities. Specifically, this filter would select
Compute nodes that supported a specific range of CPUs (i.e., num_cpus value between 1 and 4) and memory
size (i.e., mem_size of 2 or greater)
from its declared “host” capability.
|
my_node_template:
# other details omitted for
brevity
requirements:
- host:
node_filter:
capabilities:
# My “host” Compute
node needs these properties:
- host:
properties:
- num_cpus: {
in_range: [ 1, 4 ] }
- mem_size: {
greater_or_equal: 512 MB }
|
A repository definition defines a named external repository
which contains deployment and implementation artifacts that are referenced
within the TOSCA Service Template.
3.5.5.1 Keynames
The following is the list of recognized keynames for
a TOSCA repository definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
description
|
no
|
description
|
None
|
The optional description for the repository.
|
|
url
|
yes
|
string
|
None
|
The required URL or network address used to access the
repository.
|
|
credential
|
no
|
Credential
|
None
|
The optional Credential used to authorize access to the
repository.
|
3.5.5.2 Grammar
Repository definitions have one the following
grammars:
3.5.5.2.1 Single-line grammar (no credential):
3.5.5.2.2 Multi-line grammar
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
repository_name:
represents the required symbolic name of the repository as a string.
·
repository_description:
contains an optional description of the repository.
·
repository_address:
represents the required URL of the repository as a string.
·
authorization_credential:
represents the optional credentials (e.g., user ID and password) used to
authorize access to the repository.
3.5.5.3 Example
The following represents a repository definition:
|
repositories:
my_code_repo:
description: My project’s code
repository in GitHub
url:
https://github.com/my-project/
|
An artifact definition defines a named, typed file that can
be associated with Node Type or Node Template and used by orchestration engine
to facilitate deployment and implementation of interface operations.
3.5.6.1 Keynames
The following is the list of recognized keynames for
a TOSCA artifact definition when using the extended notation:
|
Keyname
|
Required
|
Type
|
Description
|
|
type
|
yes
|
string
|
The required artifact type for the artifact definition.
|
|
file
|
yes
|
string
|
The required URI string (relative or absolute) which can
be used to locate the artifact’s file.
|
|
repository
|
no
|
string
|
The optional name of the repository definition which
contains the location of the external repository that contains the artifact.
The artifact is expected to be referenceable by its file URI within the repository.
|
|
description
|
no
|
description
|
The optional description for the artifact definition.
|
|
deploy_path
|
no
|
string
|
The file path the associated file would be deployed into
within the target node’s container.
|
3.5.6.2 Grammar
Artifact definitions have one of the following
grammars:
3.5.6.2.1 Short notation
The following single-line grammar may be used when
the artifact’s type and mime type can be inferred from the file URI:
3.5.6.2.2 Extended notation:
The following multi-line grammar may be used when
the artifact’s definition’s type and mime type need to be explicitly declared:
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
artifact_name: represents
the required symbolic name of the artifact as a string.
·
artifact_description:
represents the optional description for
the artifact.
·
artifact_type_name:
represents the required artifact type
the artifact definition is based upon.
·
artifact_file_URI: represents the required URI string
(relative or absolute) which can be used to locate the artifact’s file.
·
artifact_repository_name: represents the optional name of the repository definition to use to
retrieve the associated artifact (file) from.
·
file_deployement_path:
represents the optional path the artifact_file_URI
would be copied into within the target node’s container.
3.5.6.3 Example
The following represents an artifact definition:
|
my_file_artifact:
../my_apps_files/operation_artifact.txt
|
3.5.7 Import definition
An import definition is used within a TOSCA Service Template
to locate and uniquely name another TOSCA Service Template file which has type
and template definitions to be imported (included) and referenced within
another Service Template.
3.5.7.1 Keynames
The following is the list of recognized keynames for
a TOSCA import definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
file
|
yes
|
string
|
None
|
The required symbolic name for the imported file.
|
|
repository
|
no
|
string
|
None
|
The optional symbolic name of the repository definition
where the imported file can be found as a string.
|
|
namespace_uri
|
no
|
string
|
None
|
The optional namespace URI to that will be applied to type
definitions found within the imported file as a string.
|
|
namespace_prefix
|
no
|
string
|
None
|
The optional namespace prefix (alias) that will be used to
indicate the namespace_uri when forming a qualified name (i.e., qname)
when referencing type definitions from the imported file.
|
3.5.7.2 Grammar
Import definitions have one the following grammars:
3.5.7.2.1 Single-line grammar:
|
imports:
- <file_URI_1>
- <file_URI_2>
|
3.5.7.2.2 Multi-line grammar
|
imports:
- file: <file_URI>
repository:
<repository_name>
namespace_uri:
<definition_namespace_uri>
namespace_prefix:
<definition_namespace_prefix>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
file_uri: contains the required
name (i.e., URI) of the file to be imported as a string.
·
repository_name:
represents the optional symbolic name of the repository definition where the
imported file can be found as a string.
·
namespace_uri: represents
the optional namespace URI to that will be applied to type definitions found
within the imported file as a string.
·
namespace_prefix:
represents the optional namespace prefix (alias) that will be used to indicate
the namespace_uri when forming a
qualified name (i.e., qname) when referencing type definitions from the
imported file as a string.
3.5.7.3 Example
The following represents how import definitions
would be used for the imports keyname within a TOSCA Service Template:
|
imports:
- some_definition_file:
path1/path2/some_defs.yaml
- another_definition_file:
file: path1/path2/file2.yaml
repository:
my_service_catalog
namespace_uri: http://mycompany.com/tosca/1.0/platform
namespace_prefix: mycompany
|
A property definition defines a named, typed value and
related data that can be associated with an entity defined in this
specification (e.g., Node Types, Relationship Types, Capability Types, etc.).
Properties are used by template authors to provide input values to TOSCA
entities which indicate their “desired state” when they are instantiated. The
value of a property can be retrieved using the get_property function within TOSCA Service
Templates.
3.5.8.1.1 Attribute and Property reflection
The actual state of the entity, at any point in its
lifecycle once instantiated, is reflected by Attribute definitions. TOSCA
orchestrators automatically create an attribute for every declared property
(with the same symbolic name) to allow introspection of both the desired state
(property) and actual state (attribute).
3.5.8.2 Keynames
The following is the list of recognized keynames for
a TOSCA property definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
type
|
yes
|
string
|
None
|
The required data type for the property.
|
|
description
|
no
|
description
|
None
|
The optional description for the property.
|
|
required
|
no
|
boolean
|
default: true
|
An optional key that declares a property as required (true)
or not (false).
|
|
default
|
no
|
<any>
|
None
|
An optional key that may provide a value to be used as a
default if not provided by another means.
|
|
status
|
no
|
string
|
default: supported
|
The optional status of the property relative to the
specification or implementation. See table below for valid values.
|
|
constraints
|
no
|
list of
constraint
clauses
|
None
|
The optional list of sequenced constraint clauses for the
property.
|
|
entry_schema
|
no
|
string
|
None
|
The optional key that is used to declare the name of the Datatype definition for entries of set
types such as the TOSCA list or map.
|
The following
property status values are supported:
|
Value
|
Description
|
|
supported
|
Indicates the property is supported. This is the default
value for all property definitions.
|
|
unsupported
|
Indicates the property is not supported.
|
|
experimental
|
Indicates the property is experimental and has no official
standing.
|
|
deprecated
|
Indicates the property has been deprecated by a new
specification version.
|
3.5.8.4 Grammar
Named property definitions have the following
grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
property_name: represents
the required symbolic name of the property as a string.
·
property_description:
represents the optional description of
the property.
·
property_type: represents
the required data type of the property.
·
property_required:
represents an optional boolean value (true or
false) indicating whether or not the property is required. If this keyname is
not present on a property definition, then the property SHALL be considered required
(i.e., true) by default.
·
default_value: contains a
type-compatible value that may be used as a default if not provided by another
means.
·
status_value: a string that contains a keyword that indicates the
status of the property relative to the specification or implementation.
·
property_constraints:
represents the optional sequenced list of one or more constraint clauses on the property
definition.
·
entry_description:
represents the optional description of
the entry schema.
·
entry_type: represents
the required type name for entries in a
list or map property
type.
·
entry_constraints: represents
the optional sequenced list of one or more constraint clauses on entries in a list or map property
type.
3.5.8.5 Additional Requirements
·
Implementations of the TOSCA Simple Profile SHALL
automatically reflect (i.e., make available) any property defined on an entity
as an attribute of the entity with the same name as the property.
·
A property SHALL be considered required by default
(i.e., as if the required keyname on
the definition is set to true) unless
the definition’s required keyname is
explicitly set to false.
·
The value provided on a property definition’s default keyname SHALL be type
compatible with the type declared on the definition’s type keyname.
- Constraints of a property definition SHALL be
type-compatible with the type defined for that definition.
3.5.8.6 Notes
·
This element directly maps to the PropertiesDefinition element defined as part
of the schema for most type and entities defined in the TOSCA
v1.0 specification.
- In the TOSCA v1.0 specification
constraints are expressed in the XML Schema definitions of Node Type
properties referenced in the PropertiesDefinition
element of NodeType definitions.
3.5.8.7 Example
The following represents an example of a property
definition with constraints:
|
properties:
num_cpus:
type: integer
description: Number of CPUs
requested for a software node instance.
default: 1
required: true
constraints:
- valid_values: [ 1, 2, 4, 8
]
|
This section defines the grammar for assigning values to
named properties within TOSCA Node and Relationship templates that are defined
in their corresponding named types.
3.5.9.1 Keynames
The TOSCA property assignment has no keynames.
3.5.9.2 Grammar
Property assignments have the following grammar:
3.5.9.2.1 Short notation:
The following single-line grammar may be used when a
simple value assignment is needed:
|
<property_name>:
<property_value> | { <property_value_expression> }
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
property_name: represents
the name of a property that would be used to select a property definition with
the same name within on a TOSCA entity (e.g., Node Template, Relationship
Template, etc.,) which is declared in its declared type (e.g., a Node Type,
Node Template, Capability Type, etc.).
·
property_value, property_value_expression:
represent the type-compatible value to assign to the named property. Property
values may be provided as the result from the evaluation of an expression or a
function.
An attribute definition defines a named, typed value that
can be associated with an entity defined in this specification (e.g., a Node,
Relationship or Capability Type). Specifically, it is used to expose the
“actual state” of some property of a TOSCA entity after it has been deployed
and instantiated (as set by the TOSCA orchestrator). Attribute values can be
retrieved via the get_attribute
function from the instance model and used as values to other entities within
TOSCA Service Templates.
3.5.10.1 Attribute and Property reflection
TOSCA orchestrators automatically create Attribute definitions for any Property definitions declared on the
same TOSCA entity (e.g., nodes, node capabilities and relationships) in order
to make accessible the actual (i.e., the current state) value from the running
instance of the entity.
3.5.10.2 Keynames
The following is the list of recognized keynames for
a TOSCA attribute definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
type
|
yes
|
string
|
None
|
The required data type for the attribute.
|
|
description
|
no
|
description
|
None
|
The optional description for the attribute.
|
|
default
|
no
|
<any>
|
None
|
An optional key that may provide a value to be used as a
default if not provided by another means.
This value SHALL be type compatible with the type declared
by the property definition’s type keyname.
|
|
status
|
no
|
string
|
default: supported
|
The optional status of the attribute relative to the
specification or implementation. See supported status values defined under
the Property definition section.
|
|
entry_schema
|
no
|
string
|
None
|
The optional key that is used to declare the name of the Datatype definition for entries of set
types such as the TOSCA list or map.
|
3.5.10.3 Grammar
Attribute definitions have the following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
attribute_name:
represents the required symbolic name of the attribute as a string.
·
attribute_type:
represents the required data type of the attribute.
·
attribute_description:
represents the optional description of
the attribute.
·
default_value: contains a
type-compatible value that may be used as a default if not provided by another
means.
·
status_value: contains a
value indicating the attribute’s status relative to the specification version
(e.g., supported, deprecated, etc.). Supported status values for this keyname
are defined under Property definition.
3.5.10.4 Additional Requirements
·
In addition to any explicitly defined attributes on a TOSCA
entity (e.g., Node Type, RelationshipType, etc.), implementations of the TOSCA
Simple Profile MUST automatically reflect (i.e., make available) any
property defined on an entity as an attribute of the entity with the same name
as the property.
·
Values for the default keyname MUST be derived or
calculated from other attribute or operation output values (that reflect the
actual state of the instance of the corresponding resource) and not hard-coded
or derived from a property settings or inputs (i.e., desired state).
3.5.10.5 Notes
·
Attribute definitions are very similar to Property definitions; however,
properties of entities reflect an input that carries the template author’s
requested or desired value (i.e., desired state) which the orchestrator
(attempts to) use when instantiating the entity whereas attributes reflect the
actual value (i.e., actual state) that provides the actual instantiated value.
o
For example, a property can be used to request the IP address of
a node using a property (setting); however, the actual IP address after the
node is instantiated may by different and made available by an attribute.
3.5.10.6 Example
The following represents a required attribute
definition:
|
actual_cpus:
type: integer
description: Actual number of
CPUs allocated to the node instance.
|
This section defines the grammar for assigning values to
named attributes within TOSCA Node and Relationship templates which are defined
in their corresponding named types.
3.5.11.1 Keynames
The TOSCA attribute assignment has no keynames.
3.5.11.2 Grammar
Attribute assignments have the following grammar:
3.5.11.2.1 Short notation:
The following single-line grammar may be used when a
simple value assignment is needed:
|
<attribute_name>:
<attribute_value> | { <attribute_value_expression> }
|
3.5.11.2.2 Extended notation:
The following multi-line grammar may be used when a
value assignment requires keys in addition to a simple value assignment:
|
<attribute_name>:
description:
<attribute_description>
value: <attribute_value> |
{ <attribute_value_expression> }
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
attribute_name: represents
the name of an attribute that would be used to select an attribute definition
with the same name within on a TOSCA entity (e.g., Node Template, Relationship
Template, etc.) which is declared (or reflected from a Property definition) in
its declared type (e.g., a Node Type, Node Template, Capability Type, etc.).
·
attribute_value, attribute_value_expresssion:
represent the type-compatible value to assign to the named attribute.
Attribute values may be provided as the result from the evaluation of an
expression or a function.
·
attribute_description:
represents the optional description of
the attribute.
3.5.11.3 Additional requirements
·
Attribute values MAY be provided by the underlying
implementation at runtime when requested by the get_attribute function or it MAY
be provided through the evaluation of expressions and/or functions that derive
the values from other TOSCA attributes (also at runtime).
A parameter definition is essentially a TOSCA property
definition; however, it also allows a value to be assigned to it (as for a
TOSCA property assignment). In addition, in the case of output parameters, it
can optionally inherit the data type of the value assigned to it rather than
have an explicit data type defined for it.
3.5.12.1 Keynames
The TOSCA parameter definition has all the keynames
of a TOSCA Property definition, but in addition includes the following
additional or changed keynames:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
type
|
no
|
string
|
None
|
The required data type for the parameter.
Note:
This keyname is required for a TOSCA Property definition, but is not for a
TOSCA Parameter definition.
|
|
value
|
no
|
<any>
|
N/A
|
The type-compatible value to assign to the named
parameter. Parameter values may be provided as the result from the evaluation
of an expression or a function.
|
3.5.12.2 Grammar
Named parameter definitions have the following
grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
parameter_name:
represents the required symbolic name of the parameter as a string.
·
parameter_description:
represents the optional description of
the parameter.
·
parameter_type: represents
the optional data type of the parameter. Note, this keyname is required for a
TOSCA Property definition, but is not for a TOSCA Parameter definition.
·
parameter_value, parameter_value_expresssion:
represent the type-compatible value to assign to the named parameter.
Parameter values may be provided as the result from the evaluation of an
expression or a function.
·
parameter_required:
represents an optional boolean value (true or
false) indicating whether or not the parameter is required. If this keyname is
not present on a parameter definition, then the property SHALL be considered required
(i.e., true) by default.
·
default_value: contains a
type-compatible value that may be used as a default if not provided by another
means.
·
status_value: a string that contains a keyword that indicates the
status of the parameter relative to the specification or implementation.
·
parameter_constraints:
represents the optional sequenced list of one or more constraint clauses on the parameter
definition.
·
entry_description:
represents the optional description of
the entry schema.
·
entry_type: represents
the required type name for entries in a
list or map parameter
type.
·
entry_constraints:
represents the optional sequenced list of one or more constraint clauses on entries in a list or map parameter
type.
3.5.12.3 Additional Requirements
·
A parameter SHALL be considered required by default
(i.e., as if the required keyname on
the definition is set to true) unless
the definition’s required keyname is
explicitly set to false.
·
The value provided on a parameter definition’s default keyname SHALL be type
compatible with the type declared on the definition’s type keyname.
- Constraints of a parameter definition SHALL be
type-compatible with the type defined for that definition.
3.5.12.4 Example
The following represents an example of an input
parameter definition with constraints:
|
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4, 8
]
|
The following represents an example of an (untyped)
output parameter definition:
|
outputs:
server_ip:
description: The private IP
address of the provisioned server.
value: { get_attribute: [
my_server, private_address ] }
|
An operation definition defines a named function or
procedure that can be bound to an implementation artifact (e.g., a script).
3.5.13.1 Keynames
The following is the list of recognized keynames for
a TOSCA operation definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
description
|
no
|
description
|
The optional description string for the associated named
operation.
|
|
implementation
|
no
|
string
|
The optional implementation artifact name (e.g., a script
file name within a TOSCA CSAR file).
|
|
inputs
|
no
|
list of
property definitions
|
The optional list of input properties definitions (i.e.,
parameter definitions) for operation definitions that are within TOSCA Node
or Relationship Type definitions. This includes when operation definitions
are included as part of a Requirement definition in a Node Type.
|
|
no
|
list of
property
assignments
|
The optional list of input property assignments (i.e.,
parameters assignments) for operation definitions that are within TOSCA Node
or Relationship Template definitions. This includes when operation
definitions are included as part of a Requirement assignment in a Node
Template.
|
The following is the list of recognized keynames to
be used with the implementation keyname
within a TOSCA operation definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
primary
|
no
|
string
|
The optional implementation artifact name (i.e., the
primary script file name within a TOSCA CSAR file).
|
|
dependencies
|
no
|
list of
string
|
The optional ordered list of one or more dependent or
secondary implementation artifact name which are referenced by the primary
implementation artifact (e.g., a library the script installs or a secondary
script).
|
3.5.13.2 Grammar
Operation definitions have the following grammars:
3.5.13.2.1 Short notation
The following single-line grammar may be used when
only an operation’s implementation artifact is needed:
3.5.13.2.2 Extended notation for use in Type definitions
The following multi-line grammar may be used in Node
or Relationship Type definitions when additional information about the
operation is needed:
3.5.13.2.3 Extended notation for use in Template definitions
The following multi-line grammar may be used in Node
or Relationship Template definitions when there are multiple artifacts that may
be needed for the operation to be implemented:
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
operation_name:
represents the required symbolic name of the operation as a string.
·
operation_description:
represents the optional description
string for the corresponding operation_name.
·
implementation_artifact_name:
represents the optional name (string) of an
implementation artifact definition (defined elsewhere), or the direct name of
an implementation artifact’s relative filename (e.g., a service
template-relative, path-inclusive filename or absolute file location using a
URL).
·
property_definitions:
represents the optional list of property
definitions which the TOSCA orchestrator would make available (i.e., or
pass) to the corresponding implementation artifact during its execution.
·
property_assignments:
represents the optional list of property assignments for
passing parameters to Node or Relationship Template operations providing values
for properties defined in their respective type definitions.
·
list_of_dependent_artifact_names:
represents the optional ordered list of one or more dependent or secondary
implementation artifact names (as strings) which are referenced by the primary
implementation artifact. TOSCA orchestrators will copy these files to the same
location as the primary artifact on the target node so as to make them
accessible to the primary implementation artifact when it is executed.
3.5.13.3 Additional requirements
·
The default sub-classing behavior for implementations of
operations SHALL be override. That is, implementation artifacts assigned in
subclasses override any defined in its parent class.
·
Template authors MAY provide property assignments on operation
inputs on templates that do not necessarily have a property definition defined
in its corresponding type.
·
Implementation artifact file names (e.g., script filenames) may
include file directory path names that are relative to the TOSCA service
template file itself when packaged within a TOSCA Cloud Service ARchive (CSAR)
file.
3.5.13.4 Examples
3.5.13.4.1 Single-line implementation example
|
interfaces:
Standard:
start: scripts/start_server.sh
|
3.5.13.4.2 Multi-line implementation example
|
interfaces:
Configure:
pre_configure_source:
implementation:
primary:
scripts/pre_configure_source.sh
dependencies:
- scripts/setup.sh
- binaries/library.rpm
- scripts/register.py
|
An interface definition defines a named interface that can
be associated with a Node or Relationship Type
3.5.14.1 Keynames
The following is the list of recognized keynames for
a TOSCA interface definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
inputs
|
no
|
list of
property definitions
|
The optional list of input property definitions available
to all defined operations for interface definitions that are within TOSCA
Node or Relationship Type definitions. This includes when interface
definitions are included as part of a Requirement definition in a Node Type.
|
|
no
|
list of
property
assignments
|
The optional list of input property assignments (i.e., parameters
assignments) for interface definitions that are within TOSCA Node or
Relationship Template definitions. This includes when interface definitions
are referenced as part of a Requirement assignment in a Node Template.
|
3.5.14.2 Grammar
Interface definitions have the following grammar:
3.5.14.2.1 Extended notation for use in Type definitions
The following multi-line grammar may be used in Node
or Relationship Type definitions:
3.5.14.2.2 Extended notation for use in Template definitions
The following multi-line grammar may be used in Node
or Relationship Template definitions:
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
interface_definition_name: represents
the required symbolic name of the interface as a string.
·
interface_type_name: represents the required name of the
Interface Type for the interface definition.
·
property_definitions:
represents the optional list of property definitions
(i.e., parameters) which the TOSCA orchestrator would make available (i.e., or
pass) to all defined operations.
-
This means these properties and their values would be
accessible to the implementation artifacts (e.g., scripts) associated to each
operation during their execution.
·
property_assignments:
represents the optional list of property assignments for
passing parameters to Node or Relationship Template operations providing values
for properties defined in their respective type definitions.
·
operation_definitions: represents the required name of one or more operation definitions.
An event filter definition defines criteria for selection of
an attribute, for the purpose of monitoring it, within a TOSCA entity, or one
its capabilities.
3.5.15.1 Keynames
The following is the list of recognized keynames for
a TOSCA event filter definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
node
|
yes
|
string
|
The required name of the node
type or template that contains either the attribute to be monitored or
contains the requirement that references the node that contains the
attribute to be monitored.
|
|
requirement
|
no
|
string
|
The optional name of the
requirement within the filter’s node that can be used to locate a referenced
node that contains an attribute to monitor.
|
|
capability
|
no
|
string
|
The optional name of a capability
within the filter’s node or within the node referenced by its requirement
that contains the attribute to monitor.
|
3.5.15.2 Grammar
Event filter definitions have following grammar:
|
node: <node_type_name> |
<node_template_name>
requirement:
<requirement_name>
capability:
<capability_name>
|
In the above grammar, the pseudo values that appear in
angle brackets have the following meaning:
·
node_type_name: represents
the required name of the node type that would be used to select (filter) the
node that contains the attribute to monitor or contains the requirement that
references another node that contains the attribute to monitor.
·
node_template_name: represents
the required name of the node template that would be used to select (filter)
the node that contains the attribute to monitor or contains the requirement
that references another node that contains the attribute to monitor.
·
requirement_name: represents
the optional name of the requirement that would be used to select (filter) a
referenced node that contains the attribute to monitor.
·
capability_name: represents
the optional name of a capability that would be used to select (filter) the
attribute to monitor.
3.5.16 Trigger definition
A trigger definition defines the event, condition and action
that is used to “trigger” a policy it is associated with.
3.5.16.1 Keynames
The following is the list of recognized keynames for
a TOSCA trigger definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
description
|
no
|
description
|
The optional description string for the named trigger.
|
|
event_type
|
yes
|
string
|
The required name of the event type that activates the
trigger’s action.
|
|
schedule
|
no
|
TimeInterval
|
The optional time interval during which the trigger is
valid (i.e., during which the declared actions will be processed).
|
|
target_filter
|
no
|
event filter
|
The optional filter used to locate the attribute to
monitor for the trigger’s defined condition. This filter helps locate the
TOSCA entity (i.e., node or relationship) or further a specific capability of
that entity that contains the attribute to monitor.
|
|
condition
|
no
|
constraint clause
|
The optional condition which contains an attribute constraint
that can be monitored. Note: this is optional since sometimes the event
occurrence itself is enough to trigger the action.
|
|
constraint
|
no
|
constraint clause
|
The optional condition which contains an attribute constraint
that can be monitored. Note: this is optional since sometimes the event
occurrence itself is enough to trigger the action.
|
|
period
|
no
|
scalar-unit.time
|
The optional period to use to evaluate for the condition.
|
|
evaluations
|
no
|
integer
|
The optional number of evaluations that must be performed
over the period to assert the condition exists.
|
|
method
|
no
|
string
|
The optional statistical method name to use to perform the
evaluation of the condition.
|
|
action
|
yes
|
string or operation
|
The if of the workflow to be invoked when the event is
triggered and the condition is met (i.e, evaluates to true). Or
The required operation to invoke when the event is
triggered and the condition is met (i.e., evaluates to true).
|
3.5.16.2 Grammar
Trigger definitions have the following grammars:
|
<trigger_name>:
description: <trigger_description>
# TBD: need to separate “simple”
and “full” grammar for event type name
event: <event_type_name>
type: <event_type_name>
schedule:
<time_interval_for_trigger>
target_filter:
<event_filter_definition>
condition: <attribute_constraint_clause>
constraint:
<constraint_clause>
period: <scalar-unit.time> # e.g., 60 sec
evaluations: <integer> #
e.g., 1
method: <string> # e.g.,
average
action:
<operation_definition>
|
In the above grammar, the
pseudo values that appear in angle brackets have the following meaning:
·
trigger_name: represents
the required symbolic name of the trigger as a string.
·
trigger_description:
represents the optional description
string for the corresponding trigger_name.
·
event_type_name: represents
the required name of the TOSCA Event Type that would be monitored on the
identified resource (node).
·
time_interval_for_trigger: represents the optional time interval that
the trigger is valid for.
·
event_filter_definition: represents
the optional filter to use to locate the resource (node) or capability
attribute to monitor.
·
attribute_constraint_clause: represents
the optional attribute constraint that would be used to test for a specific
condition on the monitored resource.
·
operation_definition:
represents the required action to take if the event and (optionally) condition
are met.
A workflow activity defines an operation to be performed in
a TOSCA workflow. Activities allows to:
·
Delegate the workflow for a node expected to be provided by the
orchestrator
·
Set the state of a node
·
Call an operation defined on a TOSCA interface of a node,
relationship or group
·
Inline another workflow defined in the topology (to allow
reusability)
3.5.17.1 Keynames
The following is the list of recognized keynames for
a TOSCA workflow activity definition. Note that while each of the key is not
required, one and only one of them is required (mutualy exclusive).
|
Keyname
|
Required
|
Type
|
Description
|
|
delegate
|
no
|
string
|
The name of the delegate workflow.
This activity requires the target to be provided by the
orchestrator (no-op node or relationship)
|
|
set_state
|
no
|
string
|
Value of the node state.
|
|
call_operation
|
no
|
string
|
A string that defines the name of the interface and
operation to be called on the node using the
<interface_name>.<operation_name> notation.
|
|
inline
|
no
|
string
|
The name of a workflow to be inlined.
|
3.5.17.2 Grammar
Workflow activity definitions have one of the
following grammars:
3.5.17.2.1 Delegate activity
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
delegate_workflow_name:
represents the name of the workflow of the node provided by the TOSCA
orchestrator.
3.5.17.2.2 Set state activity
|
- set_state:
<new_node_state>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
new_node_state: represents the
state that will be affected to the node once the activity is performed.
3.5.17.2.3 Call operation activity:
|
- call_operation:
<interface_name>.<operation_name>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
interface_name:
represents the name of the interface in which the operation to be called is
defined.
·
operation_name: represents the
name of the operation of the interface that will be called during the workflow
execution.
3.5.17.2.4 Inline activity
|
- inline: <workflow_name>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
workflow_name: represents
the name of the workflow to inline.
3.5.17.3 Additional Requirements
·
Keynames are mutually exclusive, i.e. an activity MUST define
only one of delegate, set_state, call_operation or inline keyname.
3.5.17.4 Example
following represents a list of workflow activity
definitions:
|
- delegate: deploy
- set_state: started
- call_operation:
tosca.interfaces.node.lifecycle.Standard.start
- inline: my_workflow
|
A workflow assertion is used to specify a single condition
on a workflow filter definition. The assertion allows to assert the value of an
attribute based on TOSCA constraints.
3.5.18.1 Keynames
The TOSCA workflow assertion definition has no
keynames.
3.5.18.2 Grammar
Workflow assertion definitions have the following
grammar:
|
<attribute_name>:
<list_of_constraint_clauses>
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
attribute_name: represents the name of an attribute
defined on the assertion context entity (node instance, relationship instance,
group instance) and from which value will be evaluated against the defined
constraint clauses.
·
list_of_constraint_clauses: represents the list of
constraint clauses that will be used to validate the attribute assertion.
3.5.18.3 Example
Following represents a workflow assertion with a
single equals constraint:
|
my_attribute: [{equal :
my_value}]
|
Following represents a workflow assertion with
mutliple constraints:
|
my_attribute:
- min_length: 8
- max_length : 10
|
A workflow condition clause definition is used to specify a
condition that can be used within a workflow precondition or workflow filter.
3.5.19.1 Keynames
The following is the list of recognized keynames for
a TOSCA workflow condition definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
and
|
no
|
list of condition
clause definition
|
An and clause allows to define sub-filter
clause definitions that must all be evaluated truly so the and clause is
considered as true.
|
|
or
|
no
|
list of condition
clause definition
|
An or clause allows to define sub-filter
clause definitions where one of them must all be evaluated truly so the or
clause is considered as true.
Note in opposite to assert
|
|
assert
|
no
|
list of assertion
definition
|
A list of filter assertions to be evaluated on entity
attributes. Assert
acts as a and
clause, i.e. every defined filter assertion must be true so the assertion is
considered as true.
|
3.5.19.2 Grammar
Workflow assertion definitions have the following grammars:
3.5.19.2.1 And clause
|
and:
<list_of_condition_clause_definition>
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
list_of_condition_clause_definition:
represents the list of condition clauses. All condition clauses MUST be
asserted to true so that the and clause is asserted to true.
3.5.19.2.2 Or clause
|
or:
<list_of_condition_clause_definition>
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
list_of_condition_clause_definition:
represents the list of condition clauses. One of the condition clause have to
be asserted to true so that the or clause is asserted to true.
3.5.19.2.3 Assert clause
|
assert:
<list_of_assertion_definition>
|
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
list_of_assertion_definition:
represents the list of assertions. All assertions MUST be asserted to true so
that the assert clause is asserted to true.
3.5.19.3 Additional Requirement
·
Keynames are mutually exclusive, i.e. a filter definition can
define only one of and, or, or assert keyname.
3.5.19.4 Notes
·
The TOSCA processor SHOULD perform assertion in the order of the
list for every defined condition clause or assertion definition.
3.5.19.5 Example
Following represents a workflow condition clause
with a single equals constraint:
|
condition:
- assert:
- my_attribute: [{equal:
my_value}]
|
Following represents a workflow condition clause with
a single equals constraints on two different attributes:
|
condition:
- assert:
- my_attribute: [{equal:
my_value}]}
- my_other_attribute: [{equal:
my_other_value}]}
|
Following represents a workflow condition clause
with a or constraint on two different assertions:
|
condition:
- or:
- assert:
- my_attribute: [{equal:
my_value}]}
- assert:
- my_other_attribute:
[{equal: my_other_value}]}
|
Following represents multiple levels of condition
clauses to build the following logic: one_attribute equal one_value AND
(my_attribute equal my_value OR my_other_attribute equal my_other_value):
|
condition:
- assert:
- one_attribute: [{equal:
one_value }]
- or:
- assert:
- my_attribute: [{equal:
my_value}]}
- assert:
- my_other_attribute:
[{equal: my_other_value}]}
|
A workflow condition can be used as a filter or precondition
to check if a workflow can be processed or not based on the state of the
instances of a TOSCA topology deployment. When not met, the workflow will not
be triggered.
3.5.20.1 Keynames
The following is the list of recognized keynames for
a TOSCA workflow condition definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
target
|
yes
|
string
|
The target of the precondition (this can be a node
template name, a group name)
|
|
target_relationship
|
no
|
string
|
The optional name of a requirement of the target in case
the precondition has to be processed on a relationship rather than a node or
group. Note that this is applicable only if the target is a node.
|
|
condition
|
no
|
list of condition
clause definitions
|
A list of workflow condition clause definitions. Assertion
between elements of the condition are evaluated as an AND condition.
|
3.5.20.2 Grammar
Workflow precondition definitions have the following
grammars:
|
- target: <target_name>
target_relationship:
<target_requirement_name>
condition:
<list_of_condition_clause_definition>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
target_name: represents the name
of a node template or group in the topology.
·
target_requirement_name:
represents the name of a requirement of the node template (in case target_name
refers to a node template.
·
list_of_condition_clause_definition:
represents the list of condition clauses to be evaluated. The value of the
resulting condition is evaluated as an AND clause between the different
elements.
A workflow step allows to define one or multiple sequenced
activities in a workflow and how they are connected to other steps in the
workflow. They are the building blocks of a declarative workflow.
3.5.21.1 Keynames
The following is the list of recognized keynames for
a TOSCA workflow step definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
target
|
yes
|
string
|
The target of the step (this can be a node template name,
a group name)
|
|
target_relationship
|
no
|
string
|
The optional name of a requirement of the target in case
the step refers to a relationship rather than a node or group. Note that this
is applicable only if the target is a node.
|
|
operation_host
|
no
|
string
|
The node on which operations should be executed (for TOSCA
call_operation activities).
This element is required only for relationships and groups
target.
If target is a relationships operation_host is required
and valid_values are SOURCE or TARGET – referring to the relationship source
or target node.
If target is a group operation_host is optional.
If not specified the operation will be triggered on every
node of the group.
If specified the valid_value is a node_type or the name of
a node template.
|
|
filter
|
no
|
list of constraint
clauses
|
Filter is a map of attribute name, list of constraint
clause that allows to provide a filtering logic.
|
|
activities
|
yes
|
list of activity_definition
|
The list of sequential activities to be performed in this
step.
|
|
on_success
|
no
|
list of string
|
The optional list of step names to be performed after this
one has been completed with success (all activities has been correctly
processed).
|
|
on_failure
|
no
|
list of string
|
The optional list of step names to be called after this
one in case one of the step activity failed.
|
3.5.21.2 Grammar
Workflow step definitions have the following
grammars:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
target_name: represents the name
of a node template or group in the topology.
·
target_requirement_name:
represents the name of a requirement of the node template (in case target_name
refers to a node template.
·
operation_host: the node
on which the operation should be executed
·
<list_of_condition_clause_definition>: represents a list of condition clause definition.
·
list_of_activity_definition: represents a list of activity definition
·
target_step_name: represents the name of another step of the
workflow.
An Entity Type is the common, base, polymorphic schema type
which is extended by TOSCA base entity type schemas (e.g., Node Type,
Relationship Type, Artifact Type, etc.) and serves to define once all the
commonly shared keynames and their types. This is a “meta” type which is
abstract and not directly instantiatable.
3.6.1.1 Keynames
The following is the list of recognized keynames for
a TOSCA Entity Type definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
derived_from
|
no
|
string
|
‘None’
is the only allowed value
|
An optional parent Entity Type name the Entity Type
derives from.
|
|
version
|
no
|
version
|
N/A
|
An optional version for the Entity Type definition.
|
|
metadata
|
no
|
map of string
|
N/A
|
Defines a section used to declare additional metadata information.
|
|
description
|
no
|
description
|
N/A
|
An optional description for the Entity Type.
|
3.6.1.2 Grammar
Entity Types have following grammar:
|
<entity_keyname>:
# The only allowed value is
‘None’
derived_from: None
version: <version_number>
metadata:
<metadata_map>
description: <interface_description>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
version_number:
represents the optional TOSCA version number
for the entity.
·
entity_description:
represents the optional description
string for the entity.
·
metadata_map: represents
the optional map of string.
3.6.1.3 Additional Requirements
·
The TOSCA Entity Type SHALL be the common base type used to
derive all other top-level base TOSCA Types.
·
The TOSCA Entity Type SHALL NOT be used to derive or create new
base types apart from those defined in this specification or a profile of this
specification.
A capability definition defines a named, typed set of data
that can be associated with Node Type or Node Template to describe a
transparent capability or feature of the software component the node describes.
3.6.2.1 Keynames
The following is the list of recognized keynames for
a TOSCA capability definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
type
|
yes
|
string
|
N/A
|
The required name of the Capability Type the capability
definition is based upon.
|
|
description
|
no
|
description
|
N/A
|
The optional description of the Capability definition.
|
|
properties
|
no
|
list of
property definitions
|
N/A
|
An optional list of property definitions for the
Capability definition.
|
|
attributes
|
no
|
list of
attribute
definitions
|
N/A
|
An optional list of attribute definitions for the
Capability definition.
|
|
valid_source_types
|
no
|
string[]
|
N/A
|
An optional list of one or more valid names of Node Types
that are supported as valid sources of any relationship established to the
declared Capability Type.
|
|
occurrences
|
no
|
range of integer
|
implied default of [1,UNBOUNDED]
|
The optional minimum and maximum occurrences for the
capability. By default, an exported Capability should allow at least one
relationship to be formed with it with a maximum of UNBOUNDED relationships.
Note: the keyword UNBOUNDED
is also supported to represent any positive integer.
|
3.6.2.2 Grammar
Capability definitions have one of the following grammars:
3.6.2.2.1 Short notation
The following grammar may be used when only a list
of capability definition names needs to be declared:
3.6.2.2.2 Extended notation
The following multi-line grammar may be used when
additional information on the capability definition is needed:
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
capability_definition_name:
represents the symbolic name of the capability as a string.
·
capability_type:
represents the required name of a capability
type the capability definition is based upon.
·
capability_description:
represents the optional description of
the capability definition.
·
property_definitions:
represents the optional list of property
definitions for the capability definition.
·
attribute_definitions:
represents the optional list of attribute
definitions for the capability definition.
·
node_type_names:
represents the optional list of one or more names of Node Types that the Capability definition
supports as valid sources for a successful relationship to be established to
itself.
3.6.2.3 Examples
The following examples show capability definitions
in both simple and full forms:
3.6.2.3.1 Simple notation example
|
# Simple notation, no properties
defined or augmented
some_capability:
mytypes.mycapabilities.MyCapabilityTypeName
|
|
# Full notation, augmenting
properties of the referenced capability type
some_capability:
type:
mytypes.mycapabilities.MyCapabilityTypeName
properties:
limit:
type: integer
default: 100
|
3.6.2.4 Additional requirements
·
Any Node Type (names) provides as values for the valid_source_types keyname SHALL be
type-compatible (i.e., derived from the same parent Node Type) with any Node
Types defined using the same keyname in the parent Capability Type.
·
Capability symbolic names SHALL be unique; it is an error if a
capability name is found to occur more than once.
3.6.2.5 Notes
- The Capability Type, in this example MyCapabilityTypeName, would be defined elsewhere and have an integer
property named limit.
- This definition directly maps to the CapabilitiesDefinition of the Node Type
entity as defined in the TOSCA v1.0 specification.
The Requirement definition describes a named requirement
(dependencies) of a TOSCA Node Type or Node template which needs to be
fulfilled by a matching Capability definition declared by another TOSCA modelable
entity. The requirement definition may itself include the specific name of the
fulfilling entity (explicitly) or provide an abstract type, along with
additional filtering characteristics, that a TOSCA orchestrator can use to
fulfill the capability at runtime (implicitly).
3.6.3.1 Keynames
The following is the list of recognized keynames for
a TOSCA requirement definition:
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
capability
|
yes
|
string
|
N/A
|
The required reserved keyname used that can be used to
provide the name of a valid Capability
Type that can fulfill the requirement.
|
|
node
|
no
|
string
|
N/A
|
The optional reserved keyname used to provide the name of
a valid Node Type that contains the
capability definition that can be used to fulfill the requirement.
|
|
relationship
|
no
|
string
|
N/A
|
The optional reserved keyname used to provide the name of
a valid Relationship Type to
construct when fulfilling the requirement.
|
|
occurrences
|
no
|
range of integer
|
implied default of [1,1]
|
The optional minimum and maximum occurrences for the
requirement.
Note: the keyword UNBOUNDED
is also supported to represent any positive integer.
|
3.6.3.1.1 Additional Keynames for multi-line relationship grammar
The Requirement definition contains the Relationship
Type information needed by TOSCA Orchestrators to construct relationships to
other TOSCA nodes with matching capabilities; however, it is sometimes
recognized that additional properties may need to be passed to the relationship
(perhaps for configuration). In these cases, additional grammar is provided so
that the Node Type may declare additional Property definitions to be used as
inputs to the Relationship Type’s declared interfaces (or specific operations
of those interfaces).
|
Keyname
|
Required
|
Type
|
Constraints
|
Description
|
|
type
|
yes
|
string
|
N/A
|
The optional reserved keyname used to provide the name of
the Relationship Type for the requirement definition’s relationship keyname.
|
|
interfaces
|
no
|
list of interface
definitions
|
N/A
|
The optional reserved keyname used to reference declared
(named) interface definitions of the corresponding Relationship Type in order
to declare additional Property definitions for these interfaces or operations
of these interfaces.
|
3.6.3.2 Grammar
Requirement definitions have one of the following
grammars:
3.6.3.2.1 Simple grammar (Capability Type only)
3.6.3.2.2 Extended grammar (with Node and Relationship Types)
3.6.3.2.3 Extended grammar for declaring Property Definitions on the
relationship’s Interfaces
The following additional multi-line grammar is
provided for the relationship keyname in order to declare new Property
definitions for inputs of known Interface definitions of the declared
Relationship Type.
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
requirement_name: represents
the required symbolic name of the requirement definition as a string.
·
capability_type_name:
represents the required name of a Capability type that can be used to fulfill
the requirement.
·
node_type_name: represents
the optional name of a TOSCA Node Type that contains the Capability Type
definition the requirement can be fulfilled by.
·
relationship_type_name:
represents the optional name of a Relationship
Type to be used to construct a relationship between this requirement
definition (i.e., in the source node) to a matching capability definition (in a
target node).
·
min_occurrences, max_occurrences:
represents the optional minimum and maximum occurrences of the requirement
(i.e., its cardinality).
·
interface_definitions:
represents one or more already declared interface definitions in the
Relationship Type (as declared on the type
keyname) allowing for the declaration of new Property definition for these
interfaces or for specific Operation definitions of these interfaces.
3.6.3.3 Additional Requirements
·
Requirement symbolic names SHALL be unique; it is an error if a
requirement name is found to occur more than once.
·
If the occurrences
keyname is not present, then the occurrence of the requirement SHALL be
one and only one; that is a default declaration as follows would be assumed:
o occurrences: [1,1]
3.6.3.4 Notes
·
This element directly maps to the RequirementsDefinition of the Node Type
entity as defined in the TOSCA v1.0 specification.
·
The requirement symbolic name is used for identification of the
requirement definition only and not relied upon for establishing any
relationships in the topology.
3.6.3.5 Requirement Type definition is a tuple
A requirement definition allows type designers to
govern which types are allowed (valid) for fulfillment using three levels of
specificity with only the Capability Type being required.
1. Node Type
(optional)
2. Relationship
Type (optional)
3. Capability
Type (required)
The first level allows selection, as shown in both
the simple or complex grammar, simply providing the node’s type using the node keyname. The second level allows
specification of the relationship type to use when connecting the requirement
to the capability using the relationship
keyname. Finally, the specific named capability type on the target node is
provided using the capability keyname.
3.6.3.5.1 Property filter
In addition to the node, relationship and capability types,
a filter, with the keyname node_filter,
may be provided to constrain the allowed set of potential target nodes based
upon their properties and their capabilities’ properties. This allows TOSCA
orchestrators to help find the “best fit” when selecting among multiple
potential target nodes for the expressed requirements.
An Artifact Type is a reusable entity that defines the type
of one or more files that are used to define implementation or deployment
artifacts that are referenced by nodes or relationships on their operations.
3.6.4.1 Keynames
The Artifact Type is a TOSCA Entity and has the
common keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Artifact Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
mime_type
|
no
|
string
|
The required mime type property for the Artifact Type.
|
|
file_ext
|
no
|
string[]
|
The required file extension property for the Artifact
Type.
|
|
properties
|
no
|
list of
property definitions
|
An optional list of property definitions for the Artifact
Type.
|
3.6.4.2 Grammar
Artifact Types have following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
artifact_type_name:
represents the name of the Artifact Type being declared as a string.
·
parent_artifact_type_name:
represents the name of the Artifact Type this Artifact Type
definition derives from (i.e., its “parent” type).
·
version_number:
represents the optional TOSCA version number
for the Artifact Type.
·
artifact_description:
represents the optional description
string for the Artifact Type.
·
mime_type_string:
represents the optional Multipurpose Internet Mail Extensions (MIME) standard
string value that describes the file contents for this type of Artifact Type as
a string.
·
file_extensions:
represents the optional list of one or more recognized file extensions for this
type of artifact type as strings.
·
property_definitions:
represents the optional list of property
definitions for the artifact type.
3.6.4.3 Examples
|
my_artifact_type:
description: Java Archive
artifact type
derived_from:
tosca.artifact.Root
mime_type: application/java-archive
file_ext: [ jar ]
|
3.6.4.4 Notes
·
The ‘mime_type’ keyname is meant to have values that are Apache
mime types such as those defined here:
http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
An Interface Type is a reusable entity that
describes a set of operations that can be used to interact with or manage a
node or relationship in a TOSCA topology.
3.6.5.1 Keynames
The Interface Type is a TOSCA Entity and has the
common keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Interface Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
inputs
|
no
|
list of
property definitions
|
The optional list of input parameter definitions.
|
3.6.5.2 Grammar
Interface Types have following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
interface_type_name:
represents the required name of the interface as a string.
·
parent_interface_type_name:
represents the name of the Interface Type
this Interface Type definition derives from (i.e., its “parent” type).
·
version_number:
represents the optional TOSCA version number
for the Interface Type.
·
interface_description:
represents the optional description
string for the Interface Type.
·
property_definitions:
represents the optional list of property
definitions (i.e., parameters) which the TOSCA orchestrator would make
available (i.e., or pass) to all implementation artifacts for operations
declared on the interface during their execution.
·
operation_definitions:
represents the required list of one or more operation definitions.
3.6.5.3 Example
The following example shows a custom interface used
to define multiple configure operations.
|
mycompany.mytypes.myinterfaces.MyConfigure:
derived_from:
tosca.interfaces.relationship.Root
description: My custom configure
Interface Type
inputs:
mode:
type: string
pre_configure_service:
description: pre-configure
operation for my service
post_configure_service:
description: post-configure
operation for my service
|
3.6.5.4 Additional Requirements
·
Interface Types MUST NOT include any implementations for
defined operations; that is, the implementation keyname is invalid.
·
The inputs keyname is
reserved and SHALL NOT be used for an operation name.
A Data Type definition defines the schema for new named
datatypes in TOSCA.
3.6.6.1 Keynames
The Data Type is a TOSCA Entity and has the common
keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Data Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
constraints
|
no
|
list of
constraint clauses
|
The optional list of sequenced
constraint clauses for the Data Type.
|
|
properties
|
no
|
list of
property definitions
|
The optional list property
definitions that comprise the schema for a complex Data Type in TOSCA.
|
3.6.6.2 Grammar
Data Types have the following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
data_type_name:
represents the required symbolic name of the Data Type as a string.
·
version_number:
represents the optional TOSCA version number
for the Data Type.
·
datatype_description: represents
the optional description for the Data
Type.
·
existing_type_name: represents
the optional name of a valid TOSCA type this new Data Type would derive from.
·
type_constraints:
represents the optional sequenced list of one or more
type-compatible constraint clauses
that restrict the Data Type.
·
property_definitions:
represents the optional list of one or more property definitions that provide the
schema for the Data Type.
3.6.6.3 Additional Requirements
·
A valid datatype definition MUST have either a valid derived_from declaration or at least one
valid property definition.
·
Any constraint clauses SHALL
be type-compatible with the type declared by the derived_from keyname.
·
If a properties keyname
is provided, it SHALL contain one or more valid property definitions.
3.6.6.4 Examples
The following example represents a Data Type definition based
upon an existing string type:
3.6.6.4.1 Defining a complex datatype
|
# define a new complex datatype
mytypes.phonenumber:
description: my phone number
datatype
properties:
countrycode:
type: integer
areacode:
type: integer
number:
type: integer
|
3.6.6.4.2 Defining a datatype derived from an existing datatype
|
# define a new datatype that
derives from existing type and extends it
mytypes.phonenumber.extended:
derived_from:
mytypes.phonenumber
description: custom phone number
type that extends the basic phonenumber type
properties:
phone_description:
type: string
constraints:
- max_length: 128
|
A Capability Type is a reusable entity that
describes a kind of capability that a Node Type can declare to expose.
Requirements (implicit or explicit) that are declared as part of one node can
be matched to (i.e., fulfilled by) the Capabilities declared by another node.
3.6.7.1 Keynames
The Capability Type is a TOSCA Entity and has the
common keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Capability Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
properties
|
no
|
list of
property definitions
|
An optional list of property definitions for the
Capability Type.
|
|
attributes
|
no
|
list of
attribute
definitions
|
An optional list of attribute definitions for the
Capability Type.
|
|
valid_source_types
|
no
|
string[]
|
An optional list of one or more valid names of Node Types
that are supported as valid sources of any relationship established to the
declared Capability Type.
|
3.6.7.2 Grammar
Capability Types have following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
capability_type_name:
represents the required name of the Capability Type being declared as a string.
·
parent_capability_type_name:
represents the name of the Capability
Type this Capability Type definition derives from (i.e., its “parent”
type).
·
version_number:
represents the optional TOSCA version number
for the Capability Type.
·
capability_description:
represents the optional description
string for the corresponding capability_type_name.
·
property_definitions:
represents an optional list of property
definitions that the Capability type exports.
·
attribute_definitions:
represents the optional list of attribute
definitions for the Capability Type.
·
node_type_names:
represents the optional list of one or more names of Node Types that the Capability Type supports
as valid sources for a successful relationship to be established to itself.
3.6.7.3 Example
|
mycompany.mytypes.myapplication.MyFeature:
derived_from:
tosca.capabilities.Root
description: a custom feature of
my company’s application
properties:
my_feature_setting:
type: string
my_feature_value:
type: integer
|
A Requirement Type is a reusable entity that
describes a kind of requirement that a Node Type can declare to expose. The
TOSCA Simple Profile seeks to simplify the need for declaring specific
Requirement Types from nodes and instead rely upon nodes declaring their
features sets using TOSCA Capability Types along with a named Feature notation.
Currently, there are no use cases in this TOSCA Simple
Profile in YAML specification that utilize an independently defined Requirement
Type. This is a desired effect as part of the simplification of the TOSCA v1.0
specification.
A Node Type is a reusable entity that defines the type of
one or more Node Templates. As such, a Node Type defines the structure of
observable properties via a Properties Definition, the Requirements and Capabilities
of the node as well as its supported interfaces.
3.6.9.1 Keynames
The Node Type is a TOSCA Entity and has the common
keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Node Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
attributes
|
no
|
list of
attribute
definitions
|
An optional list of attribute definitions for the Node
Type.
|
|
properties
|
no
|
list of
property definitions
|
An optional list of property definitions for the Node
Type.
|
|
requirements
|
no
|
list of
requirement
definitions
|
An optional sequenced list of requirement
definitions for the Node Type.
|
|
capabilities
|
no
|
list of
capability
definitions
|
An optional list of capability definitions for the Node
Type.
|
|
interfaces
|
no
|
list of
interface
definitions
|
An optional list of interface definitions supported by the
Node Type.
|
|
artifacts
|
no
|
list of
artifact definitions
|
An optional list of named artifact definitions for the
Node Type.
|
Node Types have following grammar:
In the above grammar, the
pseudo values that appear in angle brackets have the following meaning:
·
node_type_name:
represents the required symbolic name of the Node Type being declared.
·
parent_node_type_name:
represents the name (string) of the Node Type this Node Type definition derives
from (i.e., its “parent” type).
·
version_number:
represents the optional TOSCA version number
for the Node Type.
·
node_type_description:
represents the optional description
string for the corresponding node_type_name.
·
property_definitions:
represents the optional list of property
definitions for the Node Type.
·
attribute_definitions:
represents the optional list of attribute
definitions for the Node Type.
·
requirement_definitions:
represents the optional sequenced list of requirement definitions for the Node
Type.
·
capability_definitions:
represents the optional list of capability
definitions for the Node Type.
·
interface_definitions:
represents the optional list of one or more interface definitions supported by the
Node Type.
·
artifact_definitions:
represents the optional list of artifact
definitions for the Node Type.
3.6.9.3 Additional Requirements
·
Requirements are intentionally expressed as a sequenced list of
TOSCA Requirement definitions which
SHOULD be resolved (processed) in sequence order by TOSCA Orchestrators.
.
·
It is recommended that all Node Types SHOULD derive
directly (as a parent) or indirectly (as an ancestor) of the TOSCA Root Node
Type (i.e., tosca.nodes.Root) to
promote compatibility and portability. However, it is permitted to author Node
Types that do not do so.
·
TOSCA Orchestrators, having a full view of the complete
application topology template and its resultant dependency graph of nodes and
relationships, MAY prioritize how they instantiate the nodes and
relationships for the application (perhaps in parallel where possible) to
achieve the greatest efficiency
3.6.9.5 Example
|
my_company.my_types.my_app_node_type:
derived_from: tosca.nodes.SoftwareComponent
description: My company’s custom
applicaton
properties:
my_app_password:
type: string
description: application
password
constraints:
- min_length: 6
- max_length: 10
attributes:
my_app_port:
type: integer
description: application
port number
requirements:
- some_database:
capability:
EndPoint.Database
node: Database
relationship: ConnectsTo
|
A Relationship Type is a reusable entity that defines the
type of one or more relationships between Node Types or Node Templates.
3.6.10.1 Keynames
The Relationship Type is a TOSCA Entity and has the
common keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Relationship Type has the following
recognized keynames:
|
Keyname
|
Required
|
Definition/Type
|
Description
|
|
properties
|
no
|
list of
property definitions
|
An optional list of property definitions for the
Relationship Type.
|
|
attributes
|
no
|
list of
attribute
definitions
|
An optional list of attribute definitions for the
Relationship Type.
|
|
interfaces
|
no
|
list of
interface
definitions
|
An optional list of interface definitions interfaces
supported by the Relationship Type.
|
|
valid_target_types
|
no
|
string[]
|
An optional list of one or more names of Capability Types
that are valid targets for this relationship.
|
3.6.10.2 Grammar
Relationship Types have following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
relationship_type_name:
represents the required symbolic name of the Relationship Type being declared
as a string.
·
parent_relationship_type_name:
represents the name (string) of the Relationship Type this Relationship
Type definition derives from (i.e., its “parent” type).
·
relationship_description:
represents the optional description
string for the corresponding relationship_type_name.
·
version_number:
represents the optional TOSCA version number
for the Relationship Type.
·
property_definitions:
represents the optional list of property
definitions for the Relationship Type.
·
attribute_definitions:
represents the optional list of attribute
definitions for the Relationship Type.
·
interface_definitions:
represents the optional list of one or more names of valid interface definitions supported by the
Relationship Type.
·
capability_type_names:
represents one or more names of valid target types for the relationship (i.e., Capability Types).
3.6.10.3 Best Practices
·
For TOSCA application portability, it is recommended that
designers use the normative Relationship types defined in this specification
where possible and derive from them for customization purposes.
·
The TOSCA Root Relationship Type (tosca.relationships.Root) SHOULD be used to
derive new types where possible when defining new relationships types. This
assures that its normative configuration interface (tosca.interfaces.relationship.Configure) can
be used in a deterministic way by TOSCA orchestrators.
3.6.10.4 Examples
|
mycompanytypes.myrelationships.AppDependency:
derived_from:
tosca.relationships.DependsOn
valid_target_types: [
mycompanytypes.mycapabilities.SomeAppCapability ]
|
A Group Type defines logical grouping types for nodes,
typically for different management purposes. Groups can effectively be viewed
as logical nodes that are not part of the physical deployment topology of an
application, yet can have capabilities and the ability to attach policies and
interfaces that can be applied (depending on the group type) to its member
nodes.
Conceptually, group definitions allow the creation of logical
“membership” relationships to nodes in a service template that are not a part
of the application’s explicit requirement dependencies in the topology template
(i.e. those required to actually get the application deployed and running).
Instead, such logical membership allows for the introduction of things such as
group management and uniform application of policies (i.e., requirements that
are also not bound to the application itself) to the group’s members.
3.6.11.1 Keynames
The Group Type is a TOSCA Entity and has the common
keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Group Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
attributes
|
no
|
list of
attribute
definitions
|
An optional list of attribute definitions for the Group
Type.
|
|
properties
|
no
|
list of
property definitions
|
An optional list of property definitions for the Group
Type.
|
|
members
|
no
|
string[]
|
An optional list of one or more names of Node Types that
are valid (allowed) as members of the Group Type.
Note: This can be viewed by TOSCA Orchestrators as an
implied relationship from the listed members nodes to the group, but one that
does not have operational lifecycle considerations. For example, if we were
to name this as an explicit Relationship Type we might call this “MemberOf”
(group).
|
|
requirements
|
no
|
list of
requirement
definitions
|
An optional sequenced list of requirement
definitions for the Group Type.
|
|
capabilities
|
no
|
list of
capability
definitions
|
An optional list of capability definitions for the Group
Type.
|
|
interfaces
|
no
|
list of
interface
definitions
|
An optional list of interface definitions supported by the
Group Type.
|
3.6.11.2 Grammar
Group Types have one the following grammars:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
group_type_name: represents
the required symbolic name of the Group Type being declared as a string.
·
parent_group_type_name:
represents the name (string) of the Group Type this Group Type definition
derives from (i.e., its “parent” type).
·
version_number:
represents the optional TOSCA version number
for the Group Type.
·
group_description:
represents the optional description string for the corresponding group_type_name.
·
property_definitions:
represents the optional list of property
definitions for the Group Type.
·
list_of_valid_member_types:
represents the optional list of TOSCA types (e.g.,., Node, Capability or even
other Group Types) that are valid member types for being added to (i.e.,
members of) the Group Type.
·
interface_definitions:
represents the optional list of one or more interface definitions supported by the
Group Type.
3.6.11.3 Additional Requirements
·
Group definitions SHOULD NOT be used to define or
redefine relationships (dependencies) for an application that can be expressed
using normative TOSCA Relationships within a TOSCA topology template.
·
The list of values associated with the “members” keyname MUST
only contain types that or homogenous (i.e., derive from the same type
hierarchy).
3.6.11.4 Example
The following represents a Group Type definition:
|
group_types:
mycompany.mytypes.groups.placement:
description: My company’s
group type for placing nodes of type Compute
members: [ tosca.nodes.Compute
]
|
A Policy Type defines a type of requirement that affects or
governs an application or service’s topology at some stage of its lifecycle,
but is not explicitly part of the topology itself (i.e., it does not prevent
the application or service from being deployed or run if it did not exist).
3.6.12.1 Keynames
The Policy Type is a TOSCA Entity and has the common
keynames listed in section 3.6.1 TOSCA Entity Schema.
In addition, the Policy Type has the following
recognized keynames:
|
Keyname
|
Required
|
Type
|
Description
|
|
properties
|
no
|
list of
property definitions
|
An optional list of property definitions for the Policy
Type.
|
|
targets
|
no
|
string[]
|
An optional list of valid Node Types or Group Types the
Policy Type can be applied to.
Note: This can be viewed by TOSCA Orchestrators as an
implied relationship to the target nodes, but one that does not have
operational lifecycle considerations. For example, if we were to name this
as an explicit Relationship Type we might call this “AppliesTo” (node or
group).
|
|
triggers
|
no
|
list of trigger
|
An optional list of policy triggers for the Policy Type.
|
3.6.12.2 Grammar
Policy Types have the following grammar:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
policy_type_name:
represents the required symbolic name of the Policy Type being declared as a string.
·
parent_policy_type_name:
represents the name (string) of the Policy Type
this Policy Type definition derives from (i.e., its “parent” type).
·
version_number:
represents the optional TOSCA version number
for the Policy Type.
·
policy_description:
represents the optional description string for the corresponding policy_type_name.
·
property_definitions:
represents the optional list of property
definitions for the Policy Type.
·
list_of_valid_target_types:
represents the optional list of TOSCA types (i.e., Group or Node Types) that
are valid targets for this Policy Type.
·
list_of_trigger_definitions:
represents the optional list of trigger
definitions for the policy.
3.6.12.3 Example
The following represents a Policy Type definition:
|
policy_types:
mycompany.mytypes.policies.placement.Container.Linux:
description: My company’s
placement policy for linux
derived_from:
tosca.policies.Root
|
The definitions in this section provide reusable modeling
element grammars that are specific to the Node or Relationship templates.
A capability assignment allows node template authors to
assign values to properties and attributes for a named capability definition
that is part of a Node Template’s type definition.
3.7.1.1 Keynames
The following is the list of recognized keynames for
a TOSCA capability assignment:
|
Keyname
|
Required
|
Type
|
Description
|
|
properties
|
no
|
list of
property
assignments
|
An optional list of property definitions for the Capability
definition.
|
|
attributes
|
no
|
list of
attribute
assignments
|
An optional list of attribute definitions for the
Capability definition.
|
3.7.1.2 Grammar
Capability assignments have one of the following
grammars:
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
capability_definition_name: represents the symbolic name
of the capability as a string.
·
property_assignments:
represents the optional list of property assignments for the
capability definition.
·
attribute_assignments:
represents the optional list of attribute assignments for
the capability definition.
3.7.1.3 Example
The following example shows a capability assignment:
3.7.1.3.1 Notation example
|
node_templates:
some_node_template:
capabilities:
some_capability:
properties:
limit: 100
|
A Requirement assignment allows template authors to provide
either concrete names of TOSCA templates or provide abstract selection criteria
for providers to use to find matching TOSCA templates that are used to fulfill
a named requirement’s declared TOSCA Node Type.
3.7.2.1 Keynames
The following is the list of recognized keynames for
a TOSCA requirement assignment:
|
Keyname
|
Required
|
Type
|
Description
|
|
capability
|
no
|
string
|
The optional reserved keyname used to provide the name of
either a:
·
Capability definition within a target node
template that can fulfill the requirement.
·
Capability Type that the provider will use to select a
type-compatible target node template to fulfill the requirement at
runtime.
|
|
node
|
no
|
string
|
The optional reserved keyname used to identify the target
node of a relationship. specifically, it is used to provide either a:
·
Node Template name that can fulfill the target node
requirement.
·
Node Type name that the provider will use to select a
type-compatible node template to fulfill the requirement at runtime.
|
|
relationship
|
no
|
string
|
The optional reserved keyname used to provide the name of
either a:
·
Relationship Template to use to relate the source
node to the (capability in the) target node when fulfilling the
requirement.
·
Relationship Type that the provider will use to select a
type-compatible relationship template to relate the source node to the
target node at runtime.
|
|
node_filter
|
no
|
node filter
|
The optional filter definition that TOSCA orchestrators or
providers would use to select a type-compatible target node that can
fulfill the associated abstract requirement at runtime.
|
The following is the list of recognized keynames for
a TOSCA requirement assignment’s relationship
keyname which is used when Property assignments need to be provided to inputs
of declared interfaces or their operations:
|
Keyname
|
Required
|
Type
|
Description
|
|
type
|
no
|
string
|
The optional reserved keyname used to provide the name of
the Relationship Type for the requirement assignment’s relationship keyname.
|
|
properties
|
no
|
list of
interface
definitions
|
The optional reserved keyname used to reference declared
(named) interface definitions of the corresponding Relationship Type in order
to provide Property assignments for these interfaces or operations of these
interfaces.
|
3.7.2.2 Grammar
Named requirement assignments have one of the
following grammars:
3.7.2.2.1 Short notation:
The following single-line grammar may be used if
only a concrete Node Template for the target node needs to be declared in the
requirement:
This notation is only valid if the corresponding
Requirement definition in the Node Template’s parent Node Type declares (at a
minimum) a valid Capability Type which can be found in the declared target Node
Template. A valid capability definition always needs to be provided in the
requirement declaration of the source node to identify a specific
capability definition in the target node the requirement will form a
TOSCA relationship with.
3.7.2.2.2 Extended notation:
The following grammar would be used if the
requirement assignment needs to provide more information than just the Node
Template name:
3.7.2.2.3 Extended grammar with Property Assignments for the relationship’s
Interfaces
The following additional multi-line grammar is
provided for the relationship keyname in order to provide new Property
assignments for inputs of known Interface definitions of the declared
Relationship Type.
Examples of uses for the extended requirement
assignment grammar include:
·
The need to allow runtime selection of the target node based upon
an abstract Node Type rather than a concrete Node Template. This may include
use of the node_filter keyname to provide node and capability filtering
information to find the “best match” of a concrete Node Template at runtime.
·
The need to further clarify the concrete Relationship Template or
abstract Relationship Type to use when relating the source node’s requirement
to the target node’s capability.
·
The need to further clarify the concrete capability (symbolic)
name or abstract Capability Type in the target node to form a relationship
between.
·
The need to (further) constrain the occurrences of the
requirement in the instance model.
In the above grammars, the pseudo values that appear
in angle brackets have the following meaning:
·
requirement_name: represents
the symbolic name of a requirement assignment as a string.
·
node_template_name: represents
the optional name of a Node Template that contains the capability this requirement
will be fulfilled by.
·
relationship_template_name:
represents the optional name of a Relationship
Type to be used when relating the requirement appears to the capability in
the target node.
·
capability_symbolic_name:
represents the optional ordered list of specific, required capability type or
named capability definition within the target Node Type or Template.
·
node_type_name: represents
the optional name of a TOSCA Node Type the associated named requirement can be
fulfilled by. This must be a type that is compatible with the Node Type
declared on the matching requirement (same symbolic name) the requirement’s
Node Template is based upon.
·
relationship_type_name:
represents the optional name of a Relationship
Type that is compatible with the Capability Type in the target node.
·
property_assignments:
represents the optional list of property value assignments for the declared
relationship.
·
interface_assignments:
represents the optional list of interface definitions for the declared
relationship used to provide property assignments on inputs of interfaces and
operations.
·
capability_type_name:
represents the optional name of a Capability Type definition within the target
Node Type this requirement needs to form a relationship with.
·
node_filter_definition:
represents the optional node filter
TOSCA orchestrators would use to fulfill the requirement for selecting a target
node. Note that this SHALL only be valid if the node keyname’s value is a Node Type and is
invalid if it is a Node Template.
3.7.2.3 Examples
3.7.2.3.1 Example 1 – Abstract hosting requirement on a Node Type
A web application node template named ‘my_application_node_template’ of type WebApplication declares a requirement named ‘host’ that needs to be fulfilled by any node
that derives from the node type WebServer.
In this case, the node template’s type is WebApplication which already declares the
Relationship Type HostedOn to use to
relate to the target node and the Capability Type of Container to be the specific target of the
requirement in the target node.
3.7.2.3.2 Example 2 - Requirement with Node Template and a custom
Relationship Type
This example is similar to the previous example;
however, the requirement named ‘database’
describes a requirement for a connection to a database endpoint (Endpoint.Database) Capability Type in a named
node template (my_database). However,
the connection requires a custom Relationship Type (my.types.CustomDbConnection’) declared on the
keyname ‘relationship’.
|
# Example of a (database)
requirement that is fulfilled by a node template named
# “my_database”, but also requires
a custom database connection relationship
my_application_node_template:
requirements:
- database:
node: my_database
capability:
Endpoint.Database
relationship:
my.types.CustomDbConnection
|
3.7.2.3.3 Example 3 - Requirement for a Compute node with additional
selection criteria (filter)
This example shows how to extend an abstract
‘host’
requirement for a Compute
node with a filter definition that further constrains TOSCA orchestrators to
include additional properties and capabilities on the target node when
fulfilling the requirement.
A Node Template specifies the occurrence of a manageable
software component as part of an application’s topology model which is defined
in a TOSCA Service Template. A Node template is an instance of a specified
Node Type and can provide customized properties, constraints or operations
which override the defaults provided by its Node Type and its implementations.
3.7.3.1 Keynames
The following is the list of recognized keynames for
a TOSCA Node Template definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
type
|
yes
|
string
|
The required name of the Node Type the Node Template is
based upon.
|
|
description
|
no
|
description
|
An optional description for the Node Template.
|
|
metadata
|
no
|
map of string
|
Defines a section used to declare additional metadata
information.
|
|
directives
|
no
|
string[]
|
An optional list of directive values to provide processing
instructions to orchestrators and tooling.
|
|
properties
|
no
|
list of
property
assignments
|
An optional list of property value assignments for the Node
Template.
|
|
attributes
|
no
|
list of
attribute
assignments
|
An optional list of attribute value assignments for the
Node Template.
|
|
requirements
|
no
|
list of
requirement
assignments
|
An optional sequenced list of requirement
assignments for the Node Template.
|
|
capabilities
|
no
|
list of
capability
assignments
|
An optional list of capability assignments for the Node
Template.
|
|
interfaces
|
no
|
list of
interface
definitions
|
An optional list of named interface definitions for the
Node Template.
|
|
artifacts
|
no
|
list of
artifact definitions
|
An optional list of named artifact definitions for the
Node Template.
|
|
node_filter
|
no
|
node filter
|
The optional filter definition that TOSCA orchestrators
would use to select the correct target node. This keyname is only valid if
the directive has the value of “selectable” set.
|
|
copy
|
no
|
string
|
The optional (symbolic) name of another node template to
copy into (all keynames and values) and use as a basis for this node
template.
|
3.7.3.2 Grammar
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
node_template_name:
represents the required symbolic name of the Node Template being declared.
·
node_type_name:
represents the name of the Node Type the Node Template is based upon.
·
node_template_description:
represents the optional description
string for Node Template.
·
directives: represents
the optional list of processing instruction keywords (as strings) for use by
tooling and orchestrators.
·
property_assignments:
represents the optional list of property assignments for the
Node Template that provide values for properties defined in its declared Node
Type.
·
attribute_assignments:
represents the optional list of attribute assignments for
the Node Template that provide values for attributes defined in its declared
Node Type.
·
requirement_assignments:
represents the optional sequenced list of requirement assignments for the
Node Template that allow assignment of type-compatible capabilities, target
nodes, relationships and target (node filters) for use when fulfilling the
requirement at runtime.
·
capability_assignments:
represents the optional list of capability
assignments for the Node Template that augment those provided by its
declared Node Type.
·
interface_definitions:
represents the optional list of interface
definitions for the Node Template that augment those provided by its
declared Node Type.
·
artifact_definitions:
represents the optional list of artifact
definitions for the Node Template that augment those provided by its
declared Node Type.
·
node_filter_definition:
represents the optional node filter
TOSCA orchestrators would use for selecting a matching node template.
·
source_node_template_name:
represents the optional (symbolic) name of another node template to copy into
(all keynames and values) and use as a basis for this node template.
3.7.3.3 Additional requirements
·
The node_filter keyword
(and supporting grammar) SHALL only be valid if the Node Template has a directive keyname with the value of “selectable” set.
·
The source node template provided as a value on the copy keyname MUST NOT itself
use the copy keyname (i.e., it must
itself be a complete node template description and not copied from another node
template).
3.7.3.4 Example
|
node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: { get_input:
my_mysql_rootpw }
port: { get_input:
my_mysql_port }
requirements:
- host: db_server
interfaces:
Standard:
configure:
scripts/my_own_configure.sh
|
A Relationship Template specifies the occurrence of a
manageable relationship between node templates as part of an application’s topology
model that is defined in a TOSCA Service Template. A Relationship template is
an instance of a specified Relationship Type and can provide customized
properties, constraints or operations which override the defaults provided by
its Relationship Type and its implementations.
3.7.4.1 Keynames
The following is the list of recognized keynames for
a TOSCA Relationship Template definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
type
|
yes
|
string
|
The required name of the Relationship Type the
Relationship Template is based upon.
|
|
description
|
no
|
description
|
An optional description for the Relationship Template.
|
|
metadata
|
no
|
map of string
|
Defines a section used to declare additional metadata
information.
|
|
properties
|
no
|
list of
property
assignments
|
An optional list of property assignments for the
Relationship Template.
|
|
attributes
|
no
|
list of
attribute
assignments
|
An optional list of attribute assignments for the
Relationship Template.
|
|
interfaces
|
no
|
list of
interface
definitions
|
An optional list of named interface definitions for the
Node Template.
|
|
copy
|
no
|
string
|
The optional (symbolic) name of another relationship
template to copy into (all keynames and values) and use as a basis for this
relationship template.
|
3.7.4.2 Grammar
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
relationship_template_name:
represents the required symbolic name of the Relationship Template being
declared.
·
relationship_type_name:
represents the name of the Relationship Type the Relationship Template is based
upon.
·
relationship_template_description:
represents the optional description
string for the Relationship Template.
·
property_assignments:
represents the optional list of property assignments for the
Relationship Template that provide values for properties defined in its
declared Relationship Type.
·
attribute_assignments:
represents the optional list of attribute assignments for
the Relationship Template that provide values for attributes defined in its
declared Relationship Type.
·
interface_definitions:
represents the optional list of interface
definitions for the Relationship Template that augment those provided by
its declared Relationship Type.
·
source_relationship_template_name:
represents the optional (symbolic) name of another relationship template to
copy into (all keynames and values) and use as a basis for this relationship
template.
3.7.4.3 Additional requirements
·
The source relationship template provided as a value on the copy keyname MUST NOT itself use the copy keyname (i.e., it must itself be a
complete relationship template description and not copied from another
relationship template).
3.7.4.4 Example
|
relationship_templates:
storage_attachment:
type: AttachesTo
properties:
location: /my_mount_point
|
3.7.5
Group definition
A group definition defines a logical grouping of node
templates, typically for management purposes, but is separate from the
application’s topology template.
3.7.5.1 Keynames
The following is the list of recognized keynames for
a TOSCA group definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
type
|
yes
|
string
|
The required name of the group type the group definition
is based upon.
|
|
description
|
no
|
description
|
The optional description for the group definition.
|
|
metadata
|
no
|
map of string
|
Defines a section used to declare additional metadata information.
|
|
properties
|
no
|
list of
property
assignments
|
An optional list of property value assignments for the
group definition.
|
|
members
|
no
|
list of string
|
The optional list of one or more node template names that
are members of this group definition.
|
|
interfaces
|
no
|
list of
interface
definitions
|
An optional list of named interface definitions for the
group definition.
|
3.7.5.2 Grammar
Group definitions have one the following grammars:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
group_name: represents
the required symbolic name of the group as a string.
·
group_type_name:
represents the name of the Group Type the definition is based upon.
·
group_description:
contains an optional description of the group.
·
property_assignments:
represents the optional list of property assignments for the
group definition that provide values for properties defined in its declared
Group Type.
·
list_of_node_templates:
contains the required list of one or more node template names (within the same
topology template) that are members of this logical group.
·
interface_definitions:
represents the optional list of interface
definitions for the group definition that augment those provided by its
declared Group Type.
3.7.5.3 Additional Requirements
·
Group definitions SHOULD NOT be used to define or
redefine relationships (dependencies) for an application that can be expressed
using normative TOSCA Relationships within a TOSCA topology template.
3.7.5.4 Example
The following represents a group definition:
|
groups:
my_app_placement_group:
type: tosca.groups.Root
description: My application’s
logical component grouping for placement
members: [ my_web_server,
my_sql_database ]
|
A policy definition defines a policy that can be associated
with a TOSCA topology or top-level entity definition (e.g., group definition,
node template, etc.).
3.7.6.1 Keynames
The following is the list of recognized keynames for
a TOSCA policy definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
type
|
yes
|
string
|
The required name of the policy type the policy definition
is based upon.
|
|
description
|
no
|
description
|
The optional description for the policy definition.
|
|
metadata
|
no
|
map of string
|
Defines a section used to declare additional metadata
information.
|
|
properties
|
no
|
list of
property
assignments
|
An optional list of property value assignments for the
policy definition.
|
|
targets
|
no
|
string[]
|
An optional list of valid Node Templates or Groups the
Policy can be applied to.
|
3.7.6.2 Grammar
Policy definitions have one the following grammars:
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
policy_name: represents
the required symbolic name of the policy as a string.
·
policy_type_name:
represents the name of the policy the definition is based upon.
·
policy_description:
contains an optional description of the policy.
·
property_assignments:
represents the optional list of property assignments for the
policy definition that provide values for properties defined in its declared
Policy Type.
·
list_of_policy_targets:
represents the optional list of names of node templates or groups that the
policy is to applied to.
·
list_of_trigger_definitions:
represents the optional list of trigger
definitions for the policy.
3.7.6.3 Example
The following represents a policy definition:
|
policies:
- my_compute_placement_policy:
type:
tosca.policies.placement
description: Apply my
placement policy to my application’s servers
targets: [ my_server_1,
my_server_2 ]
# remainder of policy
definition left off for brevity
|
A workflow definition defines an imperative workflow that is
associated with a TOSCA topology.
3.7.7.1 Keynames
The following is the list of recognized keynames for
a TOSCA workflow definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
description
|
no
|
description
|
The optional description for the workflow definition.
|
|
metadata
|
no
|
map of string
|
Defines a section used to declare additional metadata
information.
|
|
inputs
|
no
|
list of
property definitions
|
The optional list of input parameter definitions.
|
|
preconditions
|
no
|
list of precondition
definitions
|
List of preconditions to be validated before the workflow
can be processed.
|
|
steps
|
No
|
list of step
definitions
|
An optional list of valid Node Templates or Groups the
Policy can be applied to.
|
3.7.7.2 Grammar
Imperative workflow definitions have the following
grammar:
In the above grammar, the pseudo values that appear in angle
This section defines the topology template of a cloud
application. The main ingredients of the topology template are node templates
representing components of the application and relationship templates
representing links between the components. These elements are defined in the
nested node_templates section and the
nested relationship_templates sections,
respectively. Furthermore, a topology template allows for defining input
parameters, output parameters as well as grouping of node templates.
The following is the list of recognized keynames for
a TOSCA Topology Template:
|
Keyname
|
Required
|
Type
|
Description
|
|
description
|
no
|
description
|
The optional description for the Topology Template.
|
|
inputs
|
no
|
list of
parameter
definitions
|
An optional list of input parameters (i.e., as parameter
definitions) for the Topology Template.
|
|
node_templates
|
no
|
list of
node templates
|
An optional list of node template definitions for the
Topology Template.
|
|
relationship_templates
|
no
|
list of
relationship
templates
|
An optional list of relationship templates for the
Topology Template.
|
|
groups
|
no
|
list of
group definitions
|
An optional list of Group definitions whose members are
node templates defined within this same Topology Template.
|
|
policies
|
no
|
list of
policy definitions
|
An optional list of Policy definitions for the Topology
Template.
|
|
outputs
|
no
|
list of
parameter
definitions
|
An optional list of output parameters (i.e., as parameter
definitions) for the Topology Template.
|
|
substitution_mappings
|
no
|
N/A
|
An optional declaration that exports the topology template
as an implementation of a Node type.
This also includes the mappings between the external Node
Types named capabilities and requirements to existing implementations of
those capabilities and requirements on Node templates declared within the
topology template.
|
|
workflows
|
no
|
list of imperative workflow definitions
|
An optional map of imperative workflow definition for the
Topology Template.
|
The overall grammar of the topology_template section is shown
below.–Detailed grammar definitions of the each sub-sections are provided in
subsequent subsections.
|
topology_template:
description: <template_description>
inputs:
<input_parameter_list>
outputs:
<output_parameter_list>
node_templates:
<node_template_list>
relationship_templates:
<relationship_template_list>
groups:
<group_definition_list>
policies:
-
<policy_definition_list>
workflows: <workflow_list>
# Optional declaration that
exports the Topology Template
# as an implementation of a Node
Type.
substitution_mappings:
node_type: <node_type_name>
capabilities:
<map_of_capability_mappings_to_expose>
requirements:
<map_of_requirement_mapping_to_expose>
|
In the above grammar, the pseudo values that appear
in angle brackets have the following meaning:
·
template_description:
represents the optional description
string for Topology Template.
·
input_parameter_list:
represents the optional list of input parameters (i.e., as property
definitions) for the Topology Template.
·
output_parameter_list:
represents the optional list of output parameters (i.e., as property definitions)
for the Topology Template.
·
group_definition_list:
represents the optional list of group
definitions whose members are node templates that also are defined within
this Topology Template.
·
policy_definition_list:
represents the optional sequenced list of policy definitions for the Topology
Template.
·
workflow_list: represents the
optional list of imperative workflow definitions for the Topology Template.
·
node_template_list:
represents the optional list of node
template definitions for the Topology Template.
·
relationship_template_list:
represents the optional list of relationship
templates for the Topology Template.
·
node_type_name:
represents the optional name of a Node Type
that the Topology Template implements as part of the substitution_mappings.
·
map_of_capability_mappings_to_expose:
represents the mappings that expose internal capabilities from node templates
(within the topology template) as capabilities of the Node Type definition that
is declared as part of the substitution_mappings.
·
map_of_requirement_mappings_to_expose:
represents the mappings of link requirements of the Node Type definition that
is declared as part of the substitution_mappings
to internal requirements implementations within node templates (declared within
the topology template).
More detailed explanations for each of the Topology Template
grammar’s keynames appears in the sections below.
3.8.2.1 inputs
The inputs section
provides a means to define parameters using TOSCA parameter definitions, their
allowed values via constraints and default values within a TOSCA Simple Profile
template. Input parameters defined in the inputs
section of a topology template can be mapped to properties of node templates or
relationship templates within the same topology template and can thus be used
for parameterizing the instantiation of the topology template.
This section defines topology template-level input parameter
section.
·
Inputs here would ideally be mapped to BoundaryDefinitions in
TOSCA v1.0.
·
Treat input parameters as fixed global variables (not settable
within template)
·
If not in input take default (nodes use default)
3.8.2.1.1 Grammar
The grammar of the inputs
section is as follows:
3.8.2.1.2 Examples
This section provides a set of examples for the
single elements of a topology template.
Simple inputs
example without any constraints:
|
inputs:
fooName:
type: string
description: Simple string
typed property definition with no constraints.
default: bar
|
Example of inputs
with constraints:
|
inputs:
SiteName:
type: string
description: string typed
property definition with constraints
default: My Site
constraints:
- min_length: 9
|
3.8.2.2 node_templates
The node_templates
section lists the Node Templates that describe the (software) components that
are used to compose cloud applications.
3.8.2.2.1 grammar
The grammar of the node_templates
section is a follows:
3.8.2.2.2 Example
Example of node_templates
section:
|
node_templates:
my_webapp_node_template:
type: WebApplication
my_database_node_template:
type: Database
|
3.8.2.3 relationship_templates
The relationship_templates
section lists the Relationship Templates that describe the relations between
components that are used to compose cloud applications.
Note that in the TOSCA Simple Profile, the explicit
definition of relationship templates as it was required in TOSCA v1.0 is
optional, since relationships between nodes get implicitly defined by
referencing other node templates in the requirements sections of node
templates.
3.8.2.3.1 Grammar
The grammar of the relationship_templates
section is as follows:
3.8.2.3.2 Example
Example of relationship_templates
section:
|
relationship_templates:
my_connectsto_relationship:
type:
tosca.relationships.ConnectsTo
interfaces:
Configure:
inputs:
speed: { get_attribute:
[ SOURCE, connect_speed ] }
|
3.8.2.4 outputs
The outputs section
provides a means to define the output parameters that are available from a
TOSCA Simple Profile service template. It allows for exposing attributes of
node templates or relationship templates within the containing topology_template to users of a service.
3.8.2.4.1 Grammar
The grammar of the outputs
section is as follows:
3.8.2.4.2 Example
Example of the outputs
section:
|
outputs:
server_address:
description: The first private
IP address for the provisioned server.
value: { get_attribute: [
HOST, networks, private, addresses, 0 ] }
|
3.8.2.5 groups
The groups section
allows for grouping one or more node templates within a TOSCA Service Template
and for assigning special attributes like policies to the group.
3.8.2.5.1 Grammar
The grammar of the groups
section is as follows:
3.8.2.5.2 Example
The following example shows the definition of three
Compute nodes in the node_templates
section of a topology_template as well
as the grouping of two of the Compute nodes in a group server_group_1.
|
node_templates:
server1:
type: tosca.nodes.Compute
# more details ...
server2:
type: tosca.nodes.Compute
# more details ...
server3:
type: tosca.nodes.Compute
# more details ...
groups:
# server2 and server3 are part
of the same group
server_group_1:
type: tosca.groups.Root
members: [ server2, server3 ]
|
3.8.2.6 policies
The policies section
allows for declaring policies that can be applied to entities in the topology
template.
3.8.2.6.1 Grammar
The grammar of the policies
section is as follows:
3.8.2.6.2 Example
The following example shows the definition of a
placement policy.
|
policies:
- my_placement_policy:
type:
mycompany.mytypes.policy.placement
|
3.8.2.7 Notes
·
The parameters (properties) that are listed as part of the inputs block can be mapped to PropertyMappings provided as part of BoundaryDefinitions as described by the TOSCA
v1.0 specification.
·
The node templates listed as part of the node_templates block can be mapped to the
list of NodeTemplate definitions provided
as part of TopologyTemplate of a ServiceTemplate as described by the TOSCA
v1.0 specification.
·
The relationship templates listed as part of the relationship_templates block can be mapped to
the list of RelationshipTemplate
definitions provided as part of TopologyTemplate
of a ServiceTemplate as described by
the TOSCA v1.0 specification.
·
The output parameters that are listed as part of the outputs section of a topology template can be
mapped to PropertyMappings provided as
part of BoundaryDefinitions as
described by the TOSCA v1.0 specification.
o
Note, however, that TOSCA v1.0 does not define a direction (input
vs. output) for those mappings, i.e. TOSCA v1.0 PropertyMappings are underspecified in that
respect and TOSCA Simple Profile’s inputs
and outputs provide a more concrete
definition of input and output parameters.
A TOSCA Service Template (YAML)
document contains element definitions of building blocks for cloud application,
or complete models of cloud applications. This section describes the top-level
structural elements (TOSCA keynames) along with their grammars, which are
allowed to appear in a TOSCA Service Template document.
The following is the list of recognized keynames for
a TOSCA Service Template definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
tosca_definitions_version
|
yes
|
string
|
Defines the version of the TOSCA Simple Profile
specification the template (grammar) complies with.
|
|
metadata
|
no
|
map of string
|
Defines a section used to declare additional metadata
information. Domain-specific TOSCA profile specifications may define
keynames that are required for their implementations.
|
|
description
|
no
|
description
|
Declares a description for this Service Template and its
contents.
|
|
dsl_definitions
|
no
|
N/A
|
Declares optional DSL-specific definitions and
conventions. For example, in YAML, this allows defining reusable YAML macros
(i.e., YAML alias anchors) for use throughout the TOSCA Service Template.
|
|
repositories
|
no
|
list of
Repository
definitions
|
Declares the list of external repositories which contain
artifacts that are referenced in the service template along with their
addresses and necessary credential information used to connect to them in
order to retrieve the artifacts.
|
|
imports
|
no
|
list of
Import Definitions
|
Declares import statements external TOSCA Definitions
documents. For example, these may be file location or URIs relative to the
service template file within the same TOSCA CSAR file.
|
|
artifact_types
|
no
|
list of
Artifact Types
|
This section contains an optional list of artifact type
definitions for use in the service template
|
|
data_types
|
no
|
list of
Data Types
|
Declares a list of optional TOSCA Data Type definitions.
|
|
capability_types
|
no
|
list of
Capability Types
|
This section contains an optional list of capability type
definitions for use in the service template.
|
|
interface_types
|
no
|
list of
Interface Types
|
This section contains an optional list of interface type
definitions for use in the service template.
|
|
relationship_types
|
no
|
list of
Relationship
Types
|
This section contains a set of relationship type definitions
for use in the service template.
|
|
node_types
|
no
|
list of
Node Types
|
This section contains a set of node type definitions for
use in the service template.
|
|
group_types
|
no
|
list of
Group Types
|
This section contains a list of group type definitions for
use in the service template.
|
|
policy_types
|
no
|
list of
Policy Types
|
This section contains a list of policy type definitions
for use in the service template.
|
|
topology_template
|
no
|
Topology Template definition
|
Defines the topology template of an application or
service, consisting of node templates that represent the application’s or service’s
components, as well as relationship templates representing relations between
the components.
|
3.9.1.1 Metadata keynames
The following is the list of recognized metadata
keynames for a TOSCA Service Template definition:
|
Keyname
|
Required
|
Type
|
Description
|
|
template_name
|
no
|
string
|
Declares a descriptive name for the template.
|
|
template_author
|
no
|
string
|
Declares the author(s) or owner of the template.
|
|
template_version
|
no
|
string
|
Declares the version string for the template.
|
The overall structure of a
TOSCA Service Template and its top-level key collations using the TOSCA Simple
Profile is shown below:
|
tosca_definitions_version: # Required
TOSCA Definitions version string
# Optional metadata keyname: value
pairs
metadata:
template_name:
<value> # Optional name of this service template
template_author:
<value> # Optional author of this service template
template_version:
<value> # Optional version of this service template
# Optional list of domain or
profile specific metadata keynames
# Optional description of the
definitions inside the file.
description: <template_type_description>
dsl_definitions:
# list of YAML alias anchors (or
macros)
repositories:
# list of external repository
definitions which host TOSCA artifacts
imports:
# ordered list of import
definitions
artifact_types:
# list of artifact
type definitions
data_types:
# list of datatype definitions
capability_types:
# list of capability
type definitions
# list of interface
type definitions
relationship_types:
# list of relationship
type definitions
node_types:
# list of node type definitions
group_types:
# list of group type definitions
policy_types:
# list of policy type definitions
topology_template:
# topology template definition
of the cloud application or service
|
·
TOSCA Service Templates do not have to contain a
topology_template and MAY contain simply type definitions (e.g., Artifact,
Interface, Capability, Node, Relationship Types, etc.) and be imported for use
as type definitions in other TOSCA Service Templates.
This required element provides a means to include a
reference to the TOSCA Simple Profile specification within the TOSCA
Definitions YAML file. It is an indicator for the version of the TOSCA grammar
that should be used to parse the remainder of the document.
3.9.3.1.1 Keyname
|
tosca_definitions_version
|
3.9.3.1.2 Grammar
Single-line form:
|
tosca_definitions_version:
<tosca_simple_profile_version>
|
3.9.3.1.3 Examples:
TOSCA Simple Profile version 1.0 specification using
the defined namespace alias (see Section 3.1):
|
tosca_definitions_version:
tosca_simple_yaml_1_0
|
TOSCA Simple Profile version 1.0 specification using
the fully defined (target) namespace (see Section 3.1):
This keyname is used to associate domain-specific metadata
with the Service Template. The metadata keyname allows a declaration of a map
of keynames with string values.
3.9.3.2.1 Keyname
3.9.3.2.2 Grammar
|
metadata:
<map_of_string_values>
|
3.9.3.2.3 Example
|
metadata:
creation_date: 2015-04-14
date_updated: 2015-05-01
status: developmental
|
3.9.3.3 template_name
This optional metadata keyname can be used to declare the
name of service template as a single-line string value.
3.9.3.3.1 Keyname
3.9.3.3.2 Grammar
|
template_name: <name string>
|
3.9.3.3.3 Example
|
template_name: My service template
|
3.9.3.3.4 Notes
·
Some service templates are designed to be referenced and reused
by other service templates. Therefore, in these cases, the template_name value SHOULD be designed to be
used as a unique identifier through the use of namespacing techniques.
This optional metadata keyname can be used to declare the
author(s) of the service template as a single-line string value.
3.9.3.4.1 Keyname
3.9.3.4.2 Grammar
|
template_author: <author
string>
|
3.9.3.4.3 Example
|
template_author: My service
template
|
This optional metadata keyname can be used to declare a
domain specific version of the service template as a single-line string value.
3.9.3.5.1 Keyname
3.9.3.5.2 Grammar
3.9.3.5.3 Example
3.9.3.5.4 Notes:
·
Some service templates are designed to be referenced and reused
by other service templates and have a lifecycle of their own. Therefore, in
these cases, a template_version value
SHOULD be included and used in conjunction with a unique template_name value to enable lifecycle
management of the service template and its contents.
This optional keyname provides a means to include single or
multiline descriptions within a TOSCA Simple Profile template as a scalar
string value.
3.9.3.6.1 Keyname
3.9.3.7 dsl_definitions
This optional keyname provides a section to define macros
(e.g., YAML-style macros when using the TOSCA Simple Profile in YAML
specification).
3.9.3.7.1 Keyname
3.9.3.7.2 Grammar
3.9.3.7.3 Example
|
dsl_definitions:
ubuntu_image_props:
&ubuntu_image_props
architecture: x86_64
type: linux
distribution: ubuntu
os_version: 14.04
redhat_image_props:
&redhat_image_props
architecture: x86_64
type: linux
distribution: rhel
os_version: 6.6
|
This optional keyname provides a section to define external
repositories which may contain artifacts or other TOSCA Service Templates which
might be referenced or imported by the TOSCA Service Template definition.
3.9.3.8.1 Keyname
3.9.3.8.2 Grammar
3.9.3.8.3 Example
|
repositories:
my_project_artifact_repo:
description: development
repository for TAR archives and Bash scripts
url: http://mycompany.com/repository/myproject/
|
3.9.3.9 imports
This optional keyname provides a way to import a block
sequence of one or more TOSCA Definitions documents. TOSCA Definitions
documents can contain reusable TOSCA type definitions (e.g., Node Types,
Relationship Types, Artifact Types, etc.) defined by other authors. This
mechanism provides an effective way for companies and organizations to define
normative types and/or describe their software applications for reuse in other
TOSCA Service Templates.
3.9.3.9.1 Keyname
3.9.3.9.2 Grammar
3.9.3.9.3 Example
|
# An example import of definitions
files from a location relative to the
# file location of the service
template declaring the import.
imports:
- some_definitions:
relative_path/my_defns/my_typesdefs_1.yaml
- file:
my_defns/my_typesdefs_n.yaml
repository: my_company_repo
namespace_uri: http://mycompany.com/ns/tosca/2.0
namespace_prefix: mycompany
|
3.9.3.10 artifact_types
This optional keyname lists the Artifact Types that are
defined by this Service Template.
3.9.3.10.1 Keyname
3.9.3.10.2 Grammar
3.9.3.10.3 Example
|
artifact_types:
mycompany.artifacttypes.myFileType:
derived_from:
tosca.artifacts.File
|
3.9.3.11 data_types
This optional keyname provides a section to define new data
types in TOSCA.
3.9.3.11.1 Keyname
3.9.3.11.2 Grammar
3.9.3.11.3 Example
|
data_types:
# A complex datatype definition
simple_contactinfo_type:
properties:
name:
type: string
email:
type: string
phone:
type: string
# datatype definition derived
from an existing type
full_contact_info:
derived_from:
simple_contact_info
properties:
street_address:
type: string
city:
type: string
state:
type: string
postalcode:
type: string
|
This optional keyname lists the Capability Types that
provide the reusable type definitions that can be used to describe features
Node Templates or Node Types can declare they support.
3.9.3.12.1 Keyname
3.9.3.12.2 Grammar
3.9.3.12.3 Example
|
capability_types:
mycompany.mytypes.myCustomEndpoint:
derived_from:
tosca.capabilities.Endpoint
properties:
# more details ...
mycompany.mytypes.myCustomFeature:
derived_from:
tosca.capabilities.Feature
properties:
# more details ...
|
This optional keyname lists the Interface Types that provide
the reusable type definitions that can be used to describe operations for on
TOSCA entities such as Relationship Types and Node Types.
3.9.3.13.1 Keyname
3.9.3.13.2 Grammar
3.9.3.13.3 Example
|
interface_types:
mycompany.interfaces.service.Signal:
signal_begin_receive:
description: Operation to
signal start of some message processing.
signal_end_receive:
description: Operation to
signal end of some message processed.
|
3.9.3.14 relationship_types
This optional keyname lists the Relationship Types that
provide the reusable type definitions that can be used to describe dependent
relationships between Node Templates or Node Types.
3.9.3.14.1 Keyname
3.9.3.14.2 Grammar
3.9.3.14.3 Example
|
relationship_types:
mycompany.mytypes.myCustomClientServerType:
derived_from:
tosca.relationships.HostedOn
properties:
# more details ...
mycompany.mytypes.myCustomConnectionType:
derived_from:
tosca.relationships.ConnectsTo
properties:
# more details ...
|
3.9.3.15 node_types
This optional keyname lists the Node Types that provide the
reusable type definitions for software components that Node Templates can be
based upon.
3.9.3.15.1 Keyname
3.9.3.15.2 Grammar
3.9.3.15.3 Example
|
node_types:
my_webapp_node_type:
derived_from: WebApplication
properties:
my_port:
type: integer
my_database_node_type:
derived_from: Database
capabilities:
mytypes.myfeatures.transactSQL
|
3.9.3.15.4 Notes
·
The node types listed as part of the node_types block can be mapped to the list of
NodeType definitions as described by
the TOSCA v1.0 specification.
This optional keyname lists the Group Types that are defined
by this Service Template.
3.9.3.16.1 Keyname
3.9.3.16.2 Grammar
3.9.3.16.3 Example
|
group_types:
mycompany.mytypes.myScalingGroup:
derived_from:
tosca.groups.Root
|
3.9.3.17 policy_types
This optional keyname lists the Policy Types that are
defined by this Service Template.
3.9.3.17.1 Keyname
3.9.3.17.2 Grammar
3.9.3.17.3 Example
|
policy_types:
mycompany.mytypes.myScalingPolicy:
derived_from:
tosca.policies.Scaling
|
Except for the examples, this section is normative
and includes functions that are supported for use within a TOSCA Service
Template.
The following keywords MAY be used in some TOSCA function in
place of a TOSCA Node or Relationship Template name. A TOSCA orchestrator will
interpret them at the time the function would be evaluated at runtime as
described in the table below. Note that some keywords are only valid in the
context of a certain TOSCA entity as also denoted in the table.
|
Keyword
|
Valid Contexts
|
Description
|
|
SELF
|
Node Template or Relationship Template
|
A TOSCA orchestrator will interpret this keyword as the
Node or Relationship Template instance that contains the function at the time
the function is evaluated.
|
|
SOURCE
|
Relationship Template only.
|
A TOSCA orchestrator will interpret this keyword as the
Node Template instance that is at the source end of the relationship that
contains the referencing function.
|
|
TARGET
|
Relationship Template only.
|
A TOSCA orchestrator will interpret this keyword as the
Node Template instance that is at the target end of the relationship that
contains the referencing function.
|
|
HOST
|
Node Template only
|
A TOSCA orchestrator will interpret this keyword to refer
to the all nodes that “host” the node using this reference (i.e., as
identified by its HostedOn relationship).
Specifically, TOSCA orchestrators that encounter this
keyword when evaluating the get_attribute or get_property functions
SHALL search each node along the “HostedOn” relationship chain starting at
the immediate node that hosts the node where the function was evaluated (and
then that node’s host node, and so forth) until a match is found or the
“HostedOn” relationship chain ends.
|
TOSCA orchestrators utilize certain reserved keywords in the
execution environments that implementation artifacts for Node or Relationship
Templates operations are executed in. They are used to provide information to
these implementation artifacts such as the results of TOSCA function evaluation
or information about the instance model of the TOSCA application
The following keywords are reserved environment variable
names in any TOSCA supported execution environment:
|
Keyword
|
Valid Contexts
|
Description
|
|
TARGETS
|
Relationship Template only.
|
·
For an implementation artifact
that is executed in the context of a relationship, this keyword, if present,
is used to supply a list of Node Template instances in a TOSCA application’s
instance model that are currently target of the context relationship.
·
The value of this environment
variable will be a comma-separated list of identifiers of the single target
node instances (i.e., the tosca_id attribute of the node).
|
|
TARGET
|
Relationship Template only.
|
·
For an implementation artifact
that is executed in the context of a relationship, this keyword, if present,
identifies a Node Template instance in a TOSCA application’s instance model
that is a target of the context relationship, and which is being acted upon
in the current operation.
·
The value of this environment
variable will be the identifier of the single target node instance (i.e., the
tosca_id attribute of
the node).
|
|
SOURCES
|
Relationship Template only.
|
·
For an implementation artifact
that is executed in the context of a relationship, this keyword, if present,
is used to supply a list of Node Template instances in a TOSCA application’s
instance model that are currently source of the context relationship.
·
The value of this environment
variable will be a comma-separated list of identifiers of the single source
node instances (i.e., the tosca_id attribute of the node).
|
|
SOURCE
|
Relationship Template only.
|
·
For an implementation artifact
that is executed in the context of a relationship, this keyword, if present,
identifies a Node Template instance in a TOSCA application’s instance model
that is a source of the context relationship, and which is being acted upon
in the current operation.
·
The value of this environment
variable will be the identifier of the single source node instance (i.e., the
tosca_id attribute of
the node).
|
For scripts (or implementation artifacts in general) that
run in the context of relationship operations, select properties and attributes
of both the relationship itself as well as select properties and attributes of
the source and target node(s) of the relationship can be provided to the
environment by declaring respective operation inputs.
Declared inputs from mapped properties or attributes of the
source or target node (selected via the SOURCE
or TARGET keyword) will be provided to
the environment as variables having the exact same name as the inputs. In
addition, the same values will be provided for the complete set of source or
target nodes, however prefixed with the ID if the respective nodes. By means of
the SOURCES or TARGETS variables holding the complete set of
source or target node IDs, scripts will be able to iterate over corresponding
inputs for each provided ID prefix.
The following example snippet shows an imaginary
relationship definition from a load-balancer node to worker nodes. A script is
defined for the add_target operation of
the Configure interface of the relationship, and the ip_address attribute of the target is
specified as input to the script:
|
node_templates:
load_balancer:
type: some.vendor.LoadBalancer
requirements:
- member:
relationship:
some.vendor.LoadBalancerToMember
interfaces:
Configure:
add_target:
inputs:
member_ip: {
get_attribute: [ TARGET, ip_address ] }
implementation:
scripts/configure_members.py
|
The add_target
operation will be invoked, whenever a new target member is being added to the
load-balancer. With the above inputs declaration, a member_ip environment variable that will hold
the IP address of the target being added will be provided to the configure_members.py script. In addition, the
IP addresses of all current load-balancer members will be provided as
environment variables with a naming scheme of <target
node ID>_member_ip. This will allow, for example, scripts that always
just write the complete list of load-balancer members into a configuration file
to do so instead of updating existing list, which might be more complicated.
Assuming that the TOSCA application instance
includes five load-balancer members, node1
through node5, where node5 is the current target being added, the
following environment variables (plus potentially more variables) would be
provided to the script:
|
# the ID of the current target and
the IDs of all targets
TARGET=node5
TARGETS=node1,node2,node3,node4,node5
# the input for the current target
and the inputs of all targets
member_ip=10.0.0.5
node1_member_ip=10.0.0.1
node2_member_ip=10.0.0.2
node3_member_ip=10.0.0.3
node4_member_ip=10.0.0.4
node5_member_ip=10.0.0.5
|
With code like shown in the snippet below, scripts
could then iterate of all provided member_ip
inputs:
|
#!/usr/bin/python
import os
targets =
os.environ['TARGETS'].split(',')
for t in targets:
target_ip =
os.environ.get('%s_member_ip' % t)
# do something with target_ip
...
|
The list target node types assigned to the TARGETS key in an
execution environment would have names prefixed by unique IDs that distinguish
different instances of a node in a running model Future drafts of this
specification will show examples of how these names/IDs will be expressed.
4.2.2.1 Notes
·
Target of interest is always un-prefixed. Prefix is the target
opaque ID. The IDs can be used to find the environment var. for the
corresponding target. Need an example here.
·
If you have one node that contains multiple targets this would also
be used (add or remove target operations would also use this you would get set
of all current targets).
These functions are supported within the TOSCA template for
manipulation of template data.
The concat function
is used to concatenate two or more string values within a TOSCA service
template.
4.3.1.1 Grammar
|
concat:
[<string_value_expressions_*> ]
|
4.3.1.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<string_value_expressions_*>
|
yes
|
list of
string or
string value expressions
|
A list of one or more strings (or expressions that result
in a string value) which can be concatenated together into a single string.
|
4.3.1.3 Examples
|
outputs:
description: Concatenate the URL
for a server from other template values
server_url:
value: { concat: [
'http://',
get_attribute: [ server, public_address ],
':',
get_attribute: [ server, port ] ] }
|
The token function
is used within a TOSCA service template on a string to parse out (tokenize)
substrings separated by one or more token characters within a larger string.
4.3.2.1 Grammar
|
token: [
<string_with_tokens>, <string_of_token_chars>,
<substring_index> ]
|
4.3.2.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
string_with_tokens
|
yes
|
string
|
The composite string that contains one or more substrings
separated by token characters.
|
|
string_of_token_chars
|
yes
|
string
|
The string that contains one or more token characters that
separate substrings within the composite string.
|
|
substring_index
|
yes
|
integer
|
The integer indicates the index of the substring to return
from the composite string. Note that the first substring is denoted by using
the ‘0’ (zero) integer value.
|
4.3.2.3 Examples
|
outputs:
webserver_port:
description: the port
provided at the end of my server’s endpoint’s IP address
value: { token: [
get_attribute: [ my_server, data_endpoint, ip_address ],
‘:’,
1 ] }
|
These functions are used within a service template to obtain
property values from property definitions declared elsewhere in the same
service template. These property definitions can appear either directly in the
service template itself (e.g., in the inputs section) or on entities (e.g.,
node or relationship templates) that have been modeled within the template.
Note that the get_input
and get_property functions may only
retrieve the static values of property definitions of a TOSCA application as
defined in the TOSCA Service Template. The get_attribute
function should be used to retrieve values for attribute definitions (or
property definitions reflected as attribute definitions) from the runtime
instance model of the TOSCA application (as realized by the TOSCA orchestrator).
The get_input
function is used to retrieve the values of properties declared within the inputs section of a TOSCA Service Template.
4.4.1.1 Grammar
|
get_input:
<input_property_name>
|
4.4.1.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<input_property_name>
|
yes
|
string
|
The name of the property as defined in the inputs section
of the service template.
|
4.4.1.3 Examples
|
inputs:
cpus:
type: integer
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
num_cpus: { get_input: cpus }
|
The get_property
function is used to retrieve property values between modelable entities defined
in the same service template.
4.4.2.1 Grammar
|
get_property: [
<modelable_entity_name>, <optional_req_or_cap_name>,
<property_name>, <nested_property_name_or_index_1>, ...,
<nested_property_name_or_index_n> ]
|
4.4.2.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<modelable
entity name> | SELF | SOURCE | TARGET | HOST
|
yes
|
string
|
The required name of a modelable entity (e.g., Node
Template or Relationship Template name) as declared in the service template
that contains the named property definition the function will return the
value from. See section B.1 for valid keywords.
|
|
<optional_req_or_cap_name>
|
no
|
string
|
The optional name of the requirement or capability name
within the modelable entity (i.e., the <modelable_entity_name> which
contains the named property definition the function will return the value
from.
Note: If the property definition is located in the
modelable entity directly, then this parameter MAY be omitted.
|
|
<property_name>
|
yes
|
string
|
The name of the property definition the function will
return the value from.
|
|
<nested_property_name_or_index_*>
|
no
|
string| integer
|
Some TOSCA properties are complex (i.e., composed as
nested structures). These parameters are used to dereference into the names
of these nested structures when needed.
Some properties represent list types. In these cases, an index may be
provided to reference a specific entry in the list (as named in the previous
parameter) to return.
|
4.4.2.3 Examples
The following example shows how to use the get_property function with an actual Node
Template name:
|
node_templates:
mysql_database:
type: tosca.nodes.Database
properties:
name: sql_database1
wordpress:
type:
tosca.nodes.WebApplication.WordPress
...
interfaces:
Standard:
configure:
inputs:
wp_db_name: { get_property: [ mysql_database,
name ] }
|
The following example shows
how to use the get_property function using the SELF keyword:
|
node_templates:
mysql_database:
type: tosca.nodes.Database
...
capabilities:
database_endpoint:
properties:
port: 3306
wordpress:
type:
tosca.nodes.WebApplication.WordPress
requirements:
...
- database_endpoint:
mysql_database
interfaces:
Standard:
create:
wordpress_install.sh
configure:
implementation:
wordpress_configure.sh
inputs:
...
wp_db_port: { get_property: [
SELF, database_endpoint, port ] }
|
The following example shows how to use the
get_property function using the TARGET keyword:
|
relationship_templates:
my_connection:
type: ConnectsTo
interfaces:
Configure:
inputs:
targets_value: { get_property: [ TARGET, value ] }
|
These functions (attribute functions) are used within an
instance model to obtain attribute values from instances of nodes and
relationships that have been created from an application model described in a
service template. The instances of nodes or relationships can be referenced by
their name as assigned in the service template or relative to the context where
they are being invoked.
The get_attribute
function is used to retrieve the values of named attributes declared by the
referenced node or relationship template name.
4.5.1.1 Grammar
|
get_attribute: [
<modelable_entity_name>, <optional_req_or_cap_name>,
<attribute_name>, <nested_attribute_name_or_index_1>, ...,
<nested_attribute_name_or_index_n> ]
|
4.5.1.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<modelable
entity name> | SELF | SOURCE | TARGET | HOST
|
yes
|
string
|
The required name of a modelable entity (e.g., Node
Template or Relationship Template name) as declared in the service template
that contains the named attribute definition the function will return the value
from. See section B.1 for valid keywords.
|
|
<optional_req_or_cap_name>
|
no
|
string
|
The optional name of the requirement or capability name
within the modelable entity (i.e., the <modelable_entity_name> which
contains the named attribute definition the function will return the value
from.
Note: If the attribute definition is located in
the modelable entity directly, then this parameter MAY be omitted.
|
|
<attribute_name>
|
yes
|
string
|
The name of the attribute definition the function will
return the value from.
|
|
<nested_attribute_name_or_index_*>
|
no
|
string| integer
|
Some TOSCA attributes are complex (i.e., composed as
nested structures). These parameters are used to dereference into the names
of these nested structures when needed.
Some attributes represent list
types. In these cases, an index may be provided to reference a specific entry
in the list (as named in the previous parameter) to return.
|
4.5.1.3 Examples:
The attribute functions are used in the same way as the
equivalent Property functions described above. Please see their examples and
replace “get_property” with “get_attribute” function name.
4.5.1.4 Notes
These functions are used to obtain attributes from instances
of node or relationship templates by the names they were given within the
service template that described the application model (pattern).
- These functions only work when the orchestrator can
resolve to a single node or relationship instance for the named node or
relationship. This essentially means this is acknowledged to work only
when the node or relationship template being referenced from the service template
has a cardinality of 1 (i.e., there can only be one instance of it
running).
These functions are used within an instance model to obtain
values from interface operations. These can be used in order to set an
attribute of a node instance at runtime or to pass values from one operation to
another.
The get_operation_output
function is used to retrieve the values of variables exposed / exported from an
interface operation.
4.6.1.1 Grammar
|
get_operation_output: <modelable_entity_name>,
<interface_name>, <operation_name>, <output_variable_name>
|
4.6.1.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<modelable
entity name> | SELF | SOURCE | TARGET
|
yes
|
string
|
The required name of a modelable entity (e.g., Node
Template or Relationship Template name) as declared in the service template
that implements the named interface and operation.
|
|
<interface_name>
|
Yes
|
string
|
The required name of the interface which defines the
operation.
|
|
<operation_name>
|
yes
|
string
|
The required name of the operation whose value we would
like to retrieve.
|
|
<output_variable_name>
|
Yes
|
string
|
The required name of the variable that is exposed /
exported by the operation.
|
4.6.1.3 Notes
·
If operation failed, then ignore its outputs. Orchestrators
should allow orchestrators to continue running when possible past deployment in
the lifecycle. For example, if an update fails, the application should be
allowed to continue running and some other method would be used to alert
administrators of the failure.
·
This version of the TOSCA Simple Profile does not define any
model navigation functions.
The get_nodes_of_type
function can be used to retrieve a list of all known instances of nodes of the
declared Node Type.
4.7.1.1 Grammar
|
get_nodes_of_type:
<node_type_name>
|
4.7.1.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<node_type_name>
|
yes
|
string
|
The required name of a Node Type that a TOSCA orchestrator
would use to search a running application instance in order to return all
unique, named node instances of that type.
|
4.7.1.3 Returns
|
Return Key
|
Type
|
Description
|
|
TARGETS
|
<see above>
|
The list of node instances from the current application
instance that match the node_type_name supplied as an input
parameter of this function.
|
The get_artifact function
is used to retrieve artifact location between modelable entities defined in the
same service template.
4.8.1.1 Grammar
|
get_artifact: [
<modelable_entity_name>, <artifact_name>, <location>,
<remove> ]
|
4.8.1.2 Parameters
|
Parameter
|
Required
|
Type
|
Description
|
|
<modelable entity name> | SELF | SOURCE | TARGET | HOST
|
yes
|
string
|
The required name of a modelable
entity (e.g., Node Template or Relationship Template name) as declared in the
service template that contains the named property definition the function
will return the value from. See section B.1 for valid keywords.
|
|
<artifact_name>
|
yes
|
string
|
The name of the artifact
definition the function will return the value from.
|
|
<location> | LOCAL_FILE
|
no
|
string
|
Location value must be either a
valid path e.g. ‘/etc/var/my_file’ or ‘LOCAL_FILE’.
If the value is LOCAL_FILE the
orchestrator is responsible for providing a path as the result of the get_artifact call
where the artifact file can be accessed. The orchestrator will also remove
the artifact from this location at the end of the operation.
If the location is a path
specified by the user the orchestrator is responsible to copy the artifact to
the specified location. The orchestrator will return the path as the value of
the get_artifact function
and leave the file here after the execution of the operation.
|
|
remove
|
no
|
boolean
|
Boolean flag to override the
orchestrator default behavior so it will remove or not the artifact at the
end of the operation execution.
If not specified the removal
will depends of the location e.g. removes it in case of ‘LOCAL_FILE’ and keeps it in case of a path.
If true the artifact will be
removed by the orchestrator at the end of the operation execution, if false
it will not be removed.
|
4.8.1.3 Examples
The following example uses a snippet of a WordPress
[WordPress] web application to show how to use the
get_artifact
function with an actual Node Template name:
4.8.1.3.1 Example: Retrieving artifact without specified location
|
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
...
interfaces:
Standard:
configure:
create:
implementation:
wordpress_install.sh
inputs
wp_zip: { get_artifact: [
SELF, zip ] }
artifacts:
zip: /data/wordpress.zip
|
In such implementation the TOSCA orchestrator may
provide the wordpress.zip archive as
·
a local URL (example: file://home/user/wordpress.zip)
or
·
a remote one (example: http://cloudrepo:80/files/wordpress.zip)
where some orchestrator may indeed provide some global artifact repository
management features.
4.8.1.3.2 Example: Retrieving artifact as a local path
The following example explains how to force the orchestrator
to copy the file locally before calling the operation’s implementation script:
|
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
...
interfaces:
Standard:
configure:
create:
implementation:
wordpress_install.sh
inputs
wp_zip: { get_artifact: [
SELF, zip, LOCAL_FILE] }
artifacts:
zip: /data/wordpress.zip
|
In such implementation the TOSCA orchestrator must
provide the wordpress.zip archive as a local path (example: /tmp/wordpress.zip) and will
remove it after the operation is completed.
4.8.1.3.3 Example: Retrieving artifact in a specified location
The following example explains how to force the orchestrator
to copy the file locally to a specific location before calling the operation’s
implementation script :
|
node_templates:
wordpress:
type: tosca.nodes.WebApplication.WordPress
...
interfaces:
Standard:
configure:
create:
implementation:
wordpress_install.sh
inputs
wp_zip: { get_artifact: [
SELF, zip, C:/wpdata/wp.zip ] }
artifacts:
zip: /data/wordpress.zip
|
In such implementation the TOSCA orchestrator must
provide the wordpress.zip archive as a local path (example: C:/wpdata/wp.zip ) and will let it after the
operation is completed.
Future versions of this specification will address methods
to access entity names based upon the context in which they are declared or
defined.
4.9.1.1 Goals
·
Using the full paths of modelable entity names to qualify context
with the future goal of a more robust get_attribute function: e.g.,
get_attribute( <context-based-entity-name>, <attribute name>)
Except for the examples, this section is normative
and contains normative type definitions which must be supported for conformance
to this specification.
The declarative approach is heavily dependent
of the definition of basic types that a declarative container must understand.
The definition of these types must be very clear such that the operational
semantics can be precisely followed by a declarative container to achieve the
effects intended by the modeler of a topology in an interoperable manner.
·
Assumes alignment with/dependence on XML normative types proposal
for TOSCA v1.1
·
Assumes that the normative types will be versioned and the TOSCA
TC will preserve backwards compatibility.
·
Assumes that security and access control will be addressed in
future revisions or versions of this specification.
Every normative type has three names declared:
1. Type
URI – This is the unique identifying name for the type.
a. These are
reserved names within the TOSCA namespace.
2. Shorthand
Name – This is the shorter (simpler) name that can be used in place of
its corresponding, full Type URI name.
a. These are
reserved names within TOSCA namespace that MAY be used in place of the full
Type URI.
b. Profiles
of the OASIS TOSCA Simple Profile specifcaition SHALL assure non-collision of
names for new types when they are introduced.
c. TOSCA type
designers SHOULD NOT create new types with names that would collide with any
TOSCA normative type Shorthand Name.
3. Type
Qualified Name – This is a modified Shorthand Name
that includes the “tosca:” namespace prefix which clearly
qualifies it as being part of the TOSCA namespace.
a. This name
MAY be used to assure there is no collision when types are imported from other
(non) TOSCA approved sources.
·
Case sensitivity - TOSCA Type URI, Shorthand and
Type Qualified names SHALL be treated as case sensitive.
o
The case of each type name has been carefully selected by the
TOSCA working group and TOSCA orchestrators and processors SHALL strictly
recognize the name casing as specified in this specification or any of its
approved profiles.
This is the default (root) TOSCA Root Type
definition that all complex TOSCA Data Types derive from.
5.3.1.1 Definition
The TOSCA Credential type is defined as follows:
|
tosca.datatypes.Root:
description: The TOSCA root Data
Type all other TOSCA base Data Types derive from
|
The Credential type is a complex TOSCA data Type
used when describing authorization credentials used to access network
accessible resources.
|
Shorthand Name
|
Credential
|
|
Type Qualified Name
|
tosca:Credential
|
|
Type URI
|
tosca.datatypes.Credential
|
5.3.2.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
protocol
|
no
|
string
|
None
|
The optional protocol name.
|
|
token_type
|
yes
|
string
|
default: password
|
The required token type.
|
|
token
|
yes
|
string
|
None
|
The required token used as a credential for authorization
or access to a networked resource.
|
|
keys
|
no
|
map of string
|
None
|
The optional list of protocol-specific keys or assertions.
|
|
user
|
no
|
string
|
None
|
The optional user (name or ID) used for non-token based
credentials.
|
5.3.2.2 Definition
The TOSCA Credential type is defined as follows:
|
tosca.datatypes.Credential:
derived_from:
tosca.datatypes.Root
properties:
protocol:
type: string
required: false
token_type:
type: string
default: password
token:
type: string
keys:
type: map
required: false
entry_schema:
type: string
user:
type: string
required: false
|
5.3.2.3 Additional requirements
·
TOSCA Orchestrators SHALL interpret and validate the value of the
token property based upon the value of
the token_type property.
5.3.2.4 Notes
·
Specific token types and encoding them using network protocols
are not defined or covered in this specification.
·
The use of transparent user names (IDs) or passwords are not
considered best practice.
5.3.2.5 Examples
5.3.2.5.1 Provide a simple user name and password without a protocol or
standardized token format
|
<some_tosca_entity>:
properties:
my_credential:
type: Credential
properties:
user: myusername
token: mypassword
|
5.3.2.5.2 HTTP Basic access authentication credential
|
<some_tosca_entity>:
properties:
my_credential: # type:
Credential
protocol: http
token_type: basic_auth
# Username and password are
combined into a string
# Note: this would be base64
encoded before transmission by any impl.
token: myusername:mypassword
|
5.3.2.5.3 X-Auth-Token credential
|
<some_tosca_entity>:
properties:
my_credential: # type:
Credential
protocol: xauth
token_type: X-Auth-Token
# token encoded in Base64
token:
604bbe45ac7143a79e14f3158df67091
|
5.3.2.5.4 OAuth bearer token credential
|
<some_tosca_entity>:
properties:
my_credential: # type:
Credential
protocol: oauth2
token_type: bearer
# token encoded in
Base64
token: 8ao9nE2DEjr1zCsicWMpBC |
5.3.2.6 OpenStack SSH Keypair
|
<some_tosca_entity>:
properties:
my_ssh_keypair: # type:
Credential
protocol: ssh
token_type: identifier
# token is a reference (ID)
to an existing keypair (already installed)
token: <keypair_id> |
The TimeInterval type is a complex TOSCA data Type
used when describing a period of time using the YAML ISO 8601 format to declare
the start and end times.
|
Shorthand Name
|
TimeInterval
|
|
Type Qualified Name
|
tosca:TimeInterval
|
|
Type URI
|
tosca.datatypes.TimeInterval
|
5.3.3.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
start_time
|
yes
|
timestamp
|
None
|
The inclusive start time for the time interval.
|
|
end_time
|
yes
|
timestamp
|
None
|
The inclusive end time for the time interval.
|
5.3.3.2 Definition
The TOSCA TimeInterval type is defined as follows:
|
tosca.datatypes.TimeInterval:
derived_from:
tosca.datatypes.Root
properties:
start_time:
type: timestamp
required: true
end_time:
type: timestamp
required: true
|
5.3.3.3 Examples
5.3.3.3.1 Multi-day evaluation time period
|
properties:
description:
evaluation_period: Evaluate a
service for a 5-day period across time zones
type: TimeInterval
start_time: 2016-04-04-15T00:00:00Z end_time: 2016-04-08T21:59:43.10-06:00 |
The Network type is a complex TOSCA data type used
to describe logical network information.
|
Shorthand Name
|
NetworkInfo
|
|
Type Qualified Name
|
tosca:NetworkInfo
|
|
Type URI
|
tosca.datatypes.network.NetworkInfo
|
5.3.4.1 Properties
|
Name
|
Type
|
Constraints
|
Description
|
|
network_name
|
string
|
None
|
The name of the logical network.
e.g., “public”, “private”, “admin”. etc.
|
|
network_id
|
string
|
None
|
The unique ID of for the network generated by the network
provider.
|
|
addresses
|
string []
|
None
|
The list of IP addresses assigned from the underlying
network.
|
5.3.4.2 Definition
The TOSCA NetworkInfo data type is defined as
follows:
|
tosca.datatypes.network.NetworkInfo:
derived_from:
tosca.datatypes.Root
properties:
network_name:
type: string
network_id:
type: string
addresses:
type: list
entry_schema:
type: string
|
5.3.4.3 Examples
Example usage of the NetworkInfo data type:
|
<some_tosca_entity>:
properties:
private_network:
network_name: private
network_id: 3e54214f-5c09-1bc9-9999-44100326da1b
addresses: [ 10.111.128.10 ]
|
5.3.4.4 Additional Requirements
·
It is expected that TOSCA orchestrators MUST be able to map the network_name from the TOSCA model to
underlying network model of the provider.
·
The properties (or attributes) of NetworkInfo may or may not be
required depending on usage context.
The PortInfo type is a complex TOSCA data type used
to describe network port information.
|
Shorthand Name
|
PortInfo
|
|
Type Qualified Name
|
tosca:PortInfo
|
|
Type URI
|
tosca.datatypes.network.PortInfo
|
5.3.5.1 Properties
|
Name
|
Type
|
Constraints
|
Description
|
|
port_name
|
string
|
None
|
The logical network port name.
|
|
port_id
|
string
|
None
|
The unique ID for the network port generated by the
network provider.
|
|
network_id
|
string
|
None
|
The unique ID for the network.
|
|
mac_address
|
string
|
None
|
The unique media access control address (MAC address)
assigned to the port.
|
|
addresses
|
string []
|
None
|
The list of IP address(es) assigned to the port.
|
5.3.5.2 Definition
The TOSCA PortInfo type is defined as follows:
|
tosca.datatypes.network.PortInfo:
derived_from:
tosca.datatypes.Root
properties:
port_name:
type: string
port_id:
type: string
network_id:
type: string
mac_address:
type: string
addresses:
type: list
entry_schema:
type: string
|
5.3.5.3 Examples
Example usage of the PortInfo data type:
|
ethernet_port:
properties:
port_name: port1
port_id: 2c0c7a37-691a-23a6-7709-2d10ad041467
network_id: 3e54214f-5c09-1bc9-9999-44100326da1b
mac_address: f1:18:3b:41:92:1e
addresses: [ 172.24.9.102 ]
|
5.3.5.4 Additional Requirements
·
It is expected that TOSCA orchestrators MUST be able to map the port_name from the TOSCA model to underlying
network model of the provider.
·
The properties (or attributes) of PortInfo may or may not be
required depending on usage context.
The PortDef type is a TOSCA data Type used to define
a network port.
|
Shorthand Name
|
PortDef
|
|
Type Qualified Name
|
tosca:PortDef
|
|
Type URI
|
tosca.datatypes.network.PortDef
|
5.3.6.1 Definition
The TOSCA PortDef type is defined as follows:
|
tosca.datatypes.network.PortDef:
derived_from: integer
constraints:
- in_range: [ 1, 65535 ]
|
5.3.6.2 Examples
Simple usage of a PortDef property type:
|
properties:
listen_port: 9090
|
Example declaration of a property for a custom type
based upon PortDef:
|
properties:
listen_port:
type: PortDef
default: 9000
constraints:
- in_range: [ 9000, 9090 ]
|
The PortSpec type is a complex TOSCA data Type used
when describing port specifications for a network connection.
|
Shorthand Name
|
PortSpec
|
|
Type Qualified Name
|
tosca:PortSpec
|
|
Type URI
|
tosca.datatypes.network.PortSpec
|
5.3.7.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
protocol
|
yes
|
string
|
default: tcp
|
The required protocol used on the port.
|
|
source
|
no
|
PortDef
|
See PortDef
|
The optional source port.
|
|
source_range
|
no
|
range
|
in_range: [ 1, 65536 ]
|
The optional range for source port.
|
|
target
|
no
|
PortDef
|
See PortDef
|
The optional target port.
|
|
target_range
|
no
|
range
|
in_range: [ 1, 65536 ]
|
The optional range for target port.
|
5.3.7.2 Definition
The TOSCA PortSpec type is defined as follows:
|
tosca.datatypes.network.PortSpec:
derived_from:
tosca.datatypes.Root
properties:
protocol:
type: string
required: true
default: tcp
constraints:
- valid_values: [ udp,
tcp, igmp ]
target:
type: PortDef
required: false
target_range:
type: range
required: false
constraints:
- in_range: [ 1, 65535 ]
source:
type: PortDef
required: false
source_range:
type: range
required: false
constraints:
- in_range: [ 1, 65535 ]
|
5.3.7.3 Additional requirements
·
A valid PortSpec MUST have at least one of the following
properties: target, target_range, source or source_range.
·
A valid PortSpec MUST have a value for the source property that is within the numeric
range specified by the property source_range
when source_range is specified.
·
A valid PortSpec MUST have a value for the target property that is within the numeric
range specified by the property target_range
when target_range is specified.
5.3.7.4 Examples
Example usage of the PortSpec data type:
|
# example properties in a node
template
some_endpoint:
properties:
ports:
user_port:
protocol: tcp
target: 50000
target_range: [ 20000,
60000 ]
source: 9000
source_range: [ 1000,
10000 ]
|
TOSCA Artifacts Types represent the types of packages and
files used by the orchestrator when deploying TOSCA Node or Relationship Types
or invoking their interfaces. Currently, artifacts are logically divided into
three categories:
·
Deployment Types: includes those artifacts that are used
during deployment (e.g., referenced on create and install operations) and
include packaging files such as RPMs, ZIPs, or TAR files.
·
Implementation Types: includes those artifacts that
represent imperative logic and are used to implement TOSCA Interface
operations. These typically include scripting languages such as Bash (.sh),
Chef [Chef] and Puppet [Puppet].
·
Runtime Types: includes those artifacts that are used
during runtime by a service or component of the application. This could
include a library or language runtime that is needed by an application such as
a PHP or Java library.
Note: Additional TOSCA Artifact Types will be
developed in future drafts of this specification.
This is the default (root) TOSCA Artifact Type definition that all other
TOSCA base Artifact Types derive from.
5.4.1.1 Definition
|
tosca.artifacts.Root:
description: The TOSCA Artifact
Type all other TOSCA Artifact Types derive from
|
This artifact type is used when an artifact
definition needs to have its associated file simply treated as a file and no
special handling/handlers are invoked (i.e., it is not treated as either an
implementation or deployment artifact type).
|
Shorthand Name
|
File
|
|
Type Qualified Name
|
tosca:File
|
|
Type URI
|
tosca.artifacts.File
|
5.4.2.1 Definition
This artifact type represents the parent type for
all deployment artifacts in TOSCA. This class of artifacts typically represents
a binary packaging of an application or service that is used to install/create
or deploy it as part of a node’s lifecycle.
5.4.3.1.1 Definition
|
tosca.artifacts.Deployment:
derived_from: tosca.artifacts.Root
description: TOSCA base type
for deployment artifacts
|
|
|
|
5.4.3.2 Additional Requirements
·
TOSCA Orchestrators MAY throw an error if it encounters a
non-normative deployment artifact type that it is not able to process.
This artifact type represents a parent type for any
“image” which is an opaque packaging of a TOSCA Node’s deployment (whether real
or virtual) whose contents are typically already installed and pre-configured
(i.e., “stateful”) and prepared to be run on a known target container.
|
Shorthand Name
|
Deployment.Image
|
|
Type Qualified Name
|
tosca:Deployment.Image
|
|
Type URI
|
tosca.artifacts.Deployment.Image
|
5.4.3.3.1 Definition
This artifact represents the parent type for all Virtual
Machine (VM) image and container formatted deployment artifacts. These images
contain a stateful capture of a machine (e.g., server) including operating
system and installed software along with any configurations and can be run on
another machine using a hypervisor which virtualizes typical server (i.e.,
hardware) resources.
5.4.3.4.1 Definition
5.4.3.4.2 Notes
·
Future drafts of this specification may include popular standard
VM disk image (e.g., ISO, VMI, VMDX, QCOW2, etc.) and container (e.g., OVF,
bare, etc.) formats. These would include consideration of disk formats such
as:
This artifact type represents the parent type for
all implementation artifacts in TOSCA. These artifacts are used to implement
operations of TOSCA interfaces either directly (e.g., scripts) or indirectly
(e.g., config. files).
5.4.4.1.1 Definition
|
tosca.artifacts.Implementation:
derived_from: tosca.artifacts.Root
description: TOSCA base type
for implementation artifacts
|
|
|
|
5.4.4.2 Additional Requirements
·
TOSCA Orchestrators MAY throw an error if it encounters a
non-normative implementation artifact type that it is not able to process.
5.4.4.3 tosca.artifacts.Implementation.Bash
This artifact type represents a Bash script type
that contains Bash commands that can be executed on the Unix Bash shell.
|
Shorthand Name
|
Bash
|
|
Type Qualified Name
|
tosca:Bash
|
|
Type URI
|
tosca.artifacts.Implementation.Bash
|
5.4.4.3.1 Definition
|
tosca.artifacts.Implementation.Bash:
derived_from: tosca.artifacts.Implementation
description: Script artifact for
the Unix Bash shell
mime_type: application/x-sh
file_ext: [ sh ]
|
5.4.4.4 tosca.artifacts.Implementation.Python
This artifact type represents a Python file that
contains Python language constructs that can be executed within a Python
interpreter.
|
Shorthand Name
|
Python
|
|
Type Qualified Name
|
tosca:Python
|
|
Type URI
|
tosca.artifacts.Implementation.Python
|
5.4.4.4.1 Definition
|
tosca.artifacts.Implementation.Python:
derived_from: tosca.artifacts.Implementation
description: Artifact for the
interpreted Python language
mime_type: application/x-python
file_ext: [ py ]
|
This is the default (root) TOSCA Capability Type definition
that all other TOSCA Capability Types derive from.
5.5.1.1 Definition
|
tosca.capabilities.Root:
description: The TOSCA root
Capability Type all other TOSCA base Capability Types derive from
|
The Node capability indicates the base capabilities
of a TOSCA Node Type.
|
Shorthand Name
|
Node
|
|
Type Qualified Name
|
tosca:Node
|
|
Type URI
|
tosca.capabilities.Node
|
5.5.2.1 Definition
The Compute capability, when included on a Node Type
or Template definition, indicates that the node can provide hosting on a named
compute resource.
|
Shorthand Name
|
Compute
|
|
Type Qualified Name
|
tosca:Compute
|
|
Type URI
|
tosca.capabilities.Compute
|
5.5.3.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
name
|
no
|
string
|
None
|
The otional name (or identifier) of a specific compute
resource for hosting.
|
|
num_cpus
|
no
|
integer
|
greater_or_equal: 1
|
Number of (actual or virtual) CPUs associated with the
Compute node.
|
|
cpu_frequency
|
no
|
scalar-unit.frequency
|
greater_or_equal: 0.1 GHz
|
Specifies the operating frequency of CPU's core. This
property expresses the expected frequency of one (1) CPU as provided by the
property “num_cpus”.
|
|
disk_size
|
no
|
scalar-unit.size
|
greater_or_equal: 0 MB
|
Size of the local disk available to applications running
on the Compute node (default unit is MB).
|
|
mem_size
|
no
|
scalar-unit.size
|
greater_or_equal: 0 MB
|
Size of memory available to applications running on the
Compute node (default unit is MB).
|
5.5.3.2 Definition
|
tosca.capabilities.Compute:
derived_from: tosca.capabilities.Root
properties:
name:
type: string
required: false
num_cpus:
type: integer
required: false
constraints:
- greater_or_equal: 1
cpu_frequency:
type: scalar-unit.frequency
required: false
constraints:
- greater_or_equal: 0.1
GHz
disk_size:
type: scalar-unit.size
required: false
constraints:
- greater_or_equal: 0 MB
mem_size:
type: scalar-unit.size
required: false
constraints:
- greater_or_equal: 0 MB
|
The Storage capability, when included on a Node Type
or Template definition, indicates that the node can provide addressiblity for
the resource a named network with the specified ports.
|
Shorthand Name
|
Network
|
|
Type Qualified Name
|
tosca:Network
|
|
Type URI
|
tosca.capabilities.Network
|
5.5.4.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
name
|
no
|
string
|
None
|
The otional name (or identifier) of a specific network
resource.
|
5.5.4.2 Definition
The Storage capability, when included on a Node Type
or Template definition, indicates that the node can provide a named storage
location with specified size range.
|
Shorthand Name
|
Storage
|
|
Type Qualified Name
|
tosca:Storage
|
|
Type URI
|
tosca.capabilities.Storage
|
5.5.5.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
name
|
no
|
string
|
None
|
The otional name (or identifier) of a specific storage
resource.
|
5.5.5.2 Definition
The Container capability, when included on a Node
Type or Template definition, indicates that the node can act as a container for
(or a host for) one or more other declared Node Types.
|
Shorthand Name
|
Container
|
|
Type Qualified Name
|
tosca:Container
tosca:Compute.Container
|
|
Type URI
|
tosca.capabilities.Container
tosca.capabilities.Compute.Container
|
5.5.6.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
5.5.6.2 Definition
This is the default
TOSCA type that should be used or extended to define a network endpoint
capability. This includes the information to express a basic endpoint with a
single port or a complex endpoint with multiple ports. By default the Endpoint
is assumed to represent an address on a private network unless otherwise
specified.
|
Shorthand Name
|
Endpoint
|
|
Type Qualified Name
|
tosca:Endpoint
|
|
Type URI
|
tosca.capabilities.Endpoint
|
5.5.7.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
protocol
|
yes
|
string
|
default: tcp
|
The name of the protocol (i.e., the protocol prefix) that
the endpoint accepts (any OSI Layer 4-7 protocols)
Examples: http, https, ftp, tcp, udp, etc.
|
|
port
|
no
|
PortDef
|
greater_or_equal: 1
less_or_equal: 65535
|
The optional port of the endpoint.
|
|
secure
|
no
|
boolean
|
default: false
|
Requests for the endpoint to be secure and use credentials
supplied on the ConnectsTo relationship.
|
|
url_path
|
no
|
string
|
None
|
The optional URL path of the endpoint’s address if
applicable for the protocol.
|
|
port_name
|
no
|
string
|
None
|
The optional name (or ID) of the network port this
endpoint should be bound to.
|
|
network_name
|
no
|
string
|
default: PRIVATE
|
The optional name (or ID) of the network this endpoint
should be bound to.
network_name: PRIVATE | PUBLIC |<network_name> |
<network_id>
|
|
initiator
|
no
|
string
|
one of:
·
source
·
target
·
peer
default: source
|
The optional indicator of the direction of the connection.
|
|
ports
|
no
|
map of PortSpec
|
None
|
The optional map of ports the Endpoint supports (if more
than one)
|
5.5.7.2 Attributes
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
ip_address
|
yes
|
string
|
None
|
Note: This is the IP address as propagated up by the
associated node’s host (Compute) container.
|
5.5.7.3 Definition
|
tosca.capabilities.Endpoint:
derived_from:
tosca.capabilities.Root
properties:
protocol:
type: string
required: true
default: tcp
port:
type: PortDef
required: false
secure:
type: boolean
required: false
default: false
url_path:
type: string
required: false
port_name:
type: string
required: false
network_name:
type: string
required: false
default: PRIVATE
initiator:
type: string
required: false
default: source
constraints:
- valid_values: [ source,
target, peer ]
ports:
type: map
required: false
constraints:
- min_length: 1
entry_schema:
type: PortSpec
attributes:
ip_address:
type: string
|
5.5.7.4 Additional requirements
·
Although both the port and ports properties are not required, one
of port or ports must be provided in a valid Endpoint.
This capability represents a public endpoint which
is accessible to the general internet (and its public IP address ranges).
This public endpoint capability also can be used to
create a floating (IP) address that the underlying network assigns from a pool
allocated from the application’s underlying public network. This floating
address is managed by the underlying network such that can be routed an
application’s private address and remains reliable to internet clients.
|
Shorthand Name
|
Endpoint.Public
|
|
Type Qualified Name
|
tosca:Endpoint.Public
|
|
Type URI
|
tosca.capabilities.Endpoint.Public
|
5.5.8.1 Definition
|
tosca.capabilities.Endpoint.Public:
derived_from: tosca.capabilities.Endpoint
properties:
# Change the default
network_name to use the first public network found
network_name:
type: string
default: PUBLIC
constraints:
- equal: PUBLIC
floating:
description: >
indicates that the public
address should be allocated from a pool of floating IPs that are associated
with the network.
type: boolean
default: false
status: experimental
dns_name:
description: The optional
name to register with DNS
type: string
required: false
status: experimental
|
5.5.8.2 Additional requirements
·
If the network_name is
set to the reserved value PRIVATE or if
the value is set to the name of network (or subnetwork) that is not public
(i.e., has non-public IP address ranges assigned to it) then TOSCA
Orchestrators SHALL treat this as an error.
·
If a dns_name is set,
TOSCA Orchestrators SHALL attempt to register the name in the (local) DNS
registry for the Cloud provider.
This is the default TOSCA type that should be used
or extended to define a specialized administrator endpoint capability.
|
Shorthand Name
|
Endpoint.Admin
|
|
Type Qualified Name
|
tosca:Endpoint.Admin
|
|
Type URI
|
tosca.capabilities.Endpoint.Admin
|
5.5.9.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
None
|
N/A
|
N/A
|
N/A
|
N/A
|
5.5.9.2 Definition
|
tosca.capabilities.Endpoint.Admin:
derived_from: tosca.capabilities.Endpoint
# Change Endpoint secure
indicator to true from its default of false
properties:
secure:
type: boolean
default: true
constraints:
- equal: true
|
5.5.9.3 Additional requirements
·
TOSCA Orchestrator implementations of Endpoint.Admin (and
connections to it) SHALL assure that network-level security is enforced
if possible.
This is the default TOSCA type that should be used or
extended to define a specialized database endpoint capability.
|
Shorthand Name
|
Endpoint.Database
|
|
Type Qualified Name
|
tosca:Endpoint.Database
|
|
Type URI
|
tosca.capabilities.Endpoint.Database
|
5.5.10.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
None
|
N/A
|
N/A
|
N/A
|
N/A
|
5.5.10.2 Definition
This is the default TOSCA type that should be used
or extended to define an attachment capability of a (logical) infrastructure
device node (e.g., BlockStorage
node).
|
Shorthand Name
|
Attachment
|
|
Type Qualified Name
|
tosca:Attachment
|
|
Type URI
|
tosca.capabilities.Attachment
|
5.5.11.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
5.5.11.2 Definition
This is the default TOSCA type that should be used
to express an Operating System capability for a node.
|
Shorthand Name
|
OperatingSystem
|
|
Type Qualified Name
|
tosca:OperatingSystem
|
|
Type URI
|
tosca.capabilities.OperatingSystem
|
5.5.12.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
architecture
|
no
|
string
|
None
|
The Operating System (OS) architecture.
Examples of valid values include:
x86_32, x86_64, etc.
|
|
type
|
no
|
string
|
None
|
The Operating System (OS) type.
Examples of valid values include:
linux, aix, mac, windows, etc.
|
|
distribution
|
no
|
string
|
None
|
The Operating System (OS) distribution.
Examples of valid values for an “type” of “Linux” would
include: debian, fedora, rhel and ubuntu.
|
|
version
|
no
|
version
|
None
|
The Operating System version.
|
5.5.12.2 Definition
|
tosca.capabilities.OperatingSystem:
derived_from: tosca.capabilities.Root
properties:
architecture:
type: string
required: false
type:
type: string
required: false
distribution:
type: string
required: false
version:
type: version
required: false
|
5.5.12.3 Additional Requirements
·
Please note that the string values for the properties architecture, type and distribution
SHALL be normalized to lowercase by processors of the service template for
matching purposes. For example, if a “type”
value is set to either “Linux”, “LINUX” or “linux” in a service template, the
processor would normalize all three values to “linux” for matching purposes.
This is the default TOSCA type that should be used
to express a scalability capability for a node.
|
Shorthand Name
|
Scalable
|
|
Type Qualified Name
|
tosca:Scalable
|
|
Type URI
|
tosca.capabilities.Scalable
|
5.5.13.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
min_instances
|
yes
|
integer
|
default: 1
|
This property is used to indicate the minimum number of
instances that should be created for the associated TOSCA Node Template by a
TOSCA orchestrator.
|
|
max_instances
|
yes
|
integer
|
default: 1
|
This property is used to indicate the maximum number of
instances that should be created for the associated TOSCA Node Template by a
TOSCA orchestrator.
|
|
default_instances
|
no
|
integer
|
N/A
|
An optional property that indicates the requested default
number of instances that should be the starting number of instances a TOSCA
orchestrator should attempt to allocate.
Note: The value for this property MUST be in the
range between the values set for ‘min_instances’ and ‘max_instances’
properties.
|
5.5.13.2 Definition
5.5.13.3 Notes
·
The actual number of instances for a node may be governed by a
separate scaling policy which conceptually would be associated to either a
scaling-capable node or a group of nodes in which it is defined to be a part
of. This is a planned future feature of the TOSCA Simple Profile and not
currently described.
A node type that includes the Bindable capability
indicates that it can be bound to a logical network association via a network
port.
|
Shorthand Name
|
network.Bindable
|
|
Type Qualified Name
|
tosca:network.Bindable
|
|
Type URI
|
tosca.capabilities.network.Bindable
|
5.5.14.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
5.5.14.2 Definition
There are no normative Requirement Types currently
defined in this working draft. Typically, Requirements are described against a
known Capability Type
This is the default (root) TOSCA Relationship Type
definition that all other TOSCA Relationship Types derive from.
5.7.1.1 Attributes
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
tosca_id
|
yes
|
string
|
None
|
A unique identifier of the realized instance of a
Relationship Template that derives from any TOSCA normative type.
|
|
tosca_name
|
yes
|
string
|
None
|
This attribute reflects the name of the Relationship
Template as defined in the TOSCA service template. This name is not unique
to the realized instance model of corresponding deployed application as each
template in the model can result in one or more instances (e.g., scaled) when
orchestrated to a provider environment.
|
|
state
|
yes
|
string
|
default: initial
|
The state of the relationship instance. See section “Relationship States” for
allowed values.
|
5.7.1.2 Definition
|
tosca.relationships.Root:
description: The TOSCA root
Relationship Type all other TOSCA base Relationship Types derive from
attributes:
tosca_id:
type: string
tosca_name:
type: string
interfaces:
Configure:
type: tosca.interfaces.relationship.Configure
|
This type represents a general dependency
relationship between two nodes.
|
Shorthand Name
|
DependsOn
|
|
Type Qualified Name
|
tosca:DependsOn
|
|
Type URI
|
tosca.relationships.DependsOn
|
5.7.2.1 Definition
This type represents
a hosting relationship between two nodes.
|
Shorthand Name
|
HostedOn
|
|
Type Qualified Name
|
tosca:HostedOn
|
|
Type URI
|
tosca.relationships.HostedOn
|
5.7.3.1 Definition
This type represents
a network connection relationship between two nodes.
|
Shorthand Name
|
ConnectsTo
|
|
Type Qualified Name
|
tosca:ConnectsTo
|
|
Type URI
|
tosca.relationships.ConnectsTo
|
5.7.4.1 Definition
5.7.4.2 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
credential
|
no
|
Credential
|
None
|
The security credential to use to present to the target
endpoint to for either authentication or authorization purposes.
|
This type represents
an attachment relationship between two nodes. For example, an AttachesTo
relationship type would be used for attaching a storage node to a Compute node.
|
Shorthand Name
|
AttachesTo
|
|
Type Qualified Name
|
tosca:AttachesTo
|
|
Type URI
|
tosca.relationships.AttachesTo
|
5.7.5.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
location
|
yes
|
string
|
min_length: 1
|
The relative location (e.g., path on the file system),
which provides the root location to address an attached node.
e.g., a mount point / path such as ‘/usr/data’
Note: The user must provide it and it cannot be “root”.
|
|
device
|
no
|
string
|
None
|
The logical device name which for the attached device
(which is represented by the target node in the model).
e.g., ‘/dev/hda1’
|
5.7.5.2 Attributes
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
device
|
no
|
string
|
None
|
The logical name of the device as exposed to the instance.
Note: A runtime property that gets set when the model gets
instantiated by the orchestrator.
|
5.7.5.3 Definition
This type represents
an intentional network routing between two Endpoints in different networks.
|
Shorthand Name
|
RoutesTo
|
|
Type Qualified Name
|
tosca:RoutesTo
|
|
Type URI
|
tosca.relationships.RoutesTo
|
5.7.6.1 Definition
Interfaces are reusable
entities that define a set of operations that that can be included as part of a
Node type or Relationship Type definition. Each named operations may have code
or scripts associated with them that orchestrators can execute for when
transitioning an application to a given state.
·
Designers of Node or Relationship types are not required to
actually provide/associate code or scripts with every operation for a given
interface it supports. In these cases, orchestrators SHALL consider that a “No
Operation” or “no-op”.
·
The default behavior when providing scripts for an operation in a
sub-type (sub-class) or a template of an existing type which already has a
script provided for that operation SHALL be override. Meaning that the
subclasses’ script is used in place of the parent type’s script.
·
When TOSCA Orchestrators substitute an implementation for an
abstract node in a deployed service template it SHOULD be able to present a
confirmation to the submitter to confirm the implementation chosen would be
acceptable.
This is the default (root) TOSCA Interface Type definition
that all other TOSCA Interface Types derive from.
5.8.3.1 Definition
|
tosca.interfaces.Root:
derived_from: tosca.entity.Root
description: The TOSCA root
Interface Type all other TOSCA base Interface Types derive from
|
This lifecycle interface defines the essential,
normative operations that TOSCA nodes may support.
|
Shorthand Name
|
Standard
|
|
Type Qualified Name
|
tosca: Standard
|
|
Type URI
|
tosca.interfaces.node.lifecycle.Standard
|
5.8.4.1 Definition
|
tosca.interfaces.node.lifecycle.Standard:
derived_from: tosca.interfaces.Root
create:
description: Standard
lifecycle create operation.
configure:
description: Standard
lifecycle configure operation.
start:
description: Standard
lifecycle start operation.
stop:
description: Standard
lifecycle stop operation.
delete:
description: Standard
lifecycle delete operation.
|
The create operation is generally used to create the
resource or service the node represents in the topology. TOSCA orchestrators
expect node templates to provide either a deployment artifact or an
implementation artifact of a defined artifact type that it is able to process.
This specification defines normative deployment and implementation artifact
types all TOSCA Orchestrators are expected to be able to process to support
application portability.
5.8.4.3 TOSCA Orchestrator processing of Deployment artifacts
TOSCA Orchestrators, when encountering a deployment artifact
on the create operation; will automatically attempt to deploy the artifact
based upon its artifact type. This means that no implementation artifacts
(e.g., scripts) are needed on the create operation to provide commands that
deploy or install the software.
For example, if a TOSCA Orchestrator is processing an
application with a node of type SoftwareComponent and finds that the node’s
template has a create operation that provides a filename (or references to an
artifact which describes a file) of a known TOSCA deployment artifact type such
as an Open Virtualization Format (OVF) image it will automatically deploy that
image into the SoftwareComponent’s host Compute node.
5.8.4.4 Operation sequencing and node state
The following diagrams show how TOSCA orchestrators sequence
the operations of the Standard lifecycle in normal node startup and shutdown
procedures.
The following key should be used to interpret the diagrams:
5.8.4.4.1 Normal node startup sequence diagram
The following diagram shows how the TOSCA orchestrator would invoke operations
on the Standard lifecycle to startup a node.
5.8.4.4.2 Normal node shutdown sequence diagram
The following diagram shows how the TOSCA orchestrator would
invoke operations on the Standard lifecycle to shut down a node.
The lifecycle
interfaces define the essential, normative operations that each TOSCA
Relationship Types may support.
|
Shorthand Name
|
Configure
|
|
Type Qualified Name
|
tosca:Configure
|
|
Type URI
|
tosca.interfaces.relationship.Configure
|
5.8.5.1 Definition
|
tosca.interfaces.relationship.Configure:
derived_from: tosca.interfaces.Root
pre_configure_source:
description: Operation to
pre-configure the source endpoint.
pre_configure_target:
description: Operation to
pre-configure the target endpoint.
post_configure_source:
description: Operation to
post-configure the source endpoint.
post_configure_target:
description: Operation to
post-configure the target endpoint.
add_target:
description: Operation to
notify the source node of a target node being added via a relationship.
add_source:
description: Operation to
notify the target node of a source node which is now available via a
relationship.
description:
target_changed:
description: Operation to
notify source some property or attribute of the target changed
remove_target:
description: Operation to
remove a target node.
|
5.8.5.2
Invocation Conventions
TOSCA relationships are directional
connecting a source node to a target node. When TOSCA Orchestrator connects a
source and target node together using a relationship that supports the
Configure interface it will “interleave” the operations invocations of the
Configure interface with those of the node’s own Standard lifecycle interface.
This concept is illustrated below:
5.8.5.3 Normal node start sequence with Configure relationship operations
The following diagram shows how the TOSCA orchestrator would invoke Configure
lifecycle operations in conjunction with Standard lifecycle operations during a
typical startup sequence on a node.
5.8.5.4 Node-Relationship configuration sequence
Depending on which side (i.e., source or target) of
a relationship a node is on, the orchestrator will:
·
Invoke either the pre_configure_source
or pre_configure_target operation as
supplied by the relationship on the node.
·
Invoke the node’s configure
operation.
·
Invoke either the post_configure_source
or post_configure_target as supplied by
the relationship on the node.
Note that
the pre_configure_xxx and post_configure_xxx are invoked only once per
node instance.
5.8.5.4.1 Node-Relationship add, remove and changed sequence
Since a topology template contains nodes that can
dynamically be added (and scaled), removed or changed as part of an application
instance, the Configure lifecycle includes operations that are invoked on node
instances that to notify and address these dynamic changes.
For example, a source node, of a relationship that uses the
Configure lifecycle, will have the relationship operations add_target, or remove_target invoked on it whenever a target
node instance is added or removed to the running application instance. In addition,
whenever the node state of its target node changes, the target_changed operation is invoked on it to
address this change. Conversely, the add_source
and remove_source operations are
invoked on the source node of the relationship.
5.8.5.5 Notes
·
The target (provider) MUST be active and running (i.e., all its
dependency stack MUST be fulfilled) prior to invoking add_target
·
In other words, all Requirements MUST be satisfied before it
advertises its capabilities (i.e., the attributes of the matched Capabilities
are available).
·
In other words, it cannot be “consumed” by any dependent node.
·
Conversely, since the source (consumer) needs information
(attributes) about any targets (and their attributes) being removed before it
actually goes away.
·
The remove_target operation
should only be executed if the target has had add_target
executed. BUT in truth we’re first informed about a target in pre_configure_source, so if we execute that
the source node should see remove_target
called to cleanup.
·
Error handling: If any node operation of the topology
fails processing should stop on that node template and the failing operation
(script) should return an error (failure) code when possible.
The TOSCA Root Node
Type is the default type that all other TOSCA base Node Types derive from.
This allows for all TOSCA nodes to have a consistent set of features for
modeling and management (e.g., consistent definitions for requirements,
capabilities and lifecycle interfaces).
|
Shorthand Name
|
Root
|
|
Type Qualified Name
|
tosca:Root
|
|
Type URI
|
tosca.nodes.Root
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
The TOSCA Root Node type has no specified properties.
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
tosca_id
|
yes
|
string
|
None
|
A unique identifier of the realized instance of a Node
Template that derives from any TOSCA normative type.
|
|
tosca_name
|
yes
|
string
|
None
|
This attribute reflects the name of the Node Template as
defined in the TOSCA service template. This name is not unique to the
realized instance model of corresponding deployed application as each
template in the model can result in one or more instances (e.g., scaled) when
orchestrated to a provider environment.
|
|
state
|
yes
|
string
|
default: initial
|
The state of the node instance. See section “Node States” for allowed values.
|
5.9.1.3 Definition
·
All Node Type definitions that wish to adhere to the TOSCA Simple
Profile SHOULD extend from the TOSCA Root Node Type to be assured of
compatibility and portability across implementations.
5.9.2 tosca.nodes.Compute
The TOSCA Compute
node represents one or more real or virtual processors of software applications
or services along with other essential local resources. Collectively, the
resources the compute node represents can logically be viewed as a (real or
virtual) “server”.
|
Shorthand Name
|
Compute
|
|
Type Qualified Name
|
tosca:Compute
|
|
Type URI
|
tosca.nodes.Compute
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
private_address
|
no
|
string
|
None
|
The primary private IP address assigned by the cloud
provider that applications may use to access the Compute node.
|
|
public_address
|
no
|
string
|
None
|
The primary public IP address assigned by the cloud
provider that applications may use to access the Compute node.
|
|
networks
|
no
|
map of NetworkInfo
|
None
|
The list of logical networks assigned to the compute host
instance and information about them.
|
|
ports
|
no
|
map of PortInfo
|
None
|
The list of logical ports assigned to the compute host
instance and information about them.
|
5.9.2.3 Definition
·
The underlying implementation of the Compute node SHOULD have the
ability to instantiate guest operating systems (either actual or virtualized)
based upon the OperatingSystem capability properties if they are supplied in
the a node template derived from the Compute node type.
The TOSCA SoftwareComponent
node represents a generic software component that can be managed and run by a
TOSCA Compute Node Type.
|
Shorthand Name
|
SoftwareComponent
|
|
Type Qualified Name
|
tosca:SoftwareComponent
|
|
Type URI
|
tosca.nodes.SoftwareComponent
|
5.9.3.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
component_version
|
no
|
version
|
None
|
The optional software component’s version.
|
|
admin_credential
|
no
|
Credential
|
None
|
The optional credential that can be used to authenticate
to the software component.
|
5.9.3.2 Attributes
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
5.9.3.3 Definition
5.9.3.4 Additional Requirements
·
Nodes that can directly be managed and run by a TOSCA Compute Node Type SHOULD extend from
this type.
This TOSA WebServer
Node Type represents an abstract software component or service that is capable
of hosting and providing management operations for one or more WebApplication nodes.
|
Shorthand Name
|
WebServer
|
|
Type Qualified Name
|
tosca:WebServer
|
|
Type URI
|
tosca.nodes.WebServer
|
5.9.4.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
None
|
N/A
|
N/A
|
N/A
|
N/A
|
5.9.4.2 Definition
5.9.4.3 Additional Requirements
·
This node SHALL export both a secure endpoint capability
(i.e., admin_endpoint), typically for
administration, as well as a regular endpoint (i.e., data_endpoint) for serving data.
The TOSCA WebApplication
node represents a software application that can be managed and run by a TOSCA WebServer node. Specific types of web
applications such as Java, etc. could be derived from this type.
|
Shorthand Name
|
WebApplication
|
|
Type Qualified Name
|
tosca: WebApplication
|
|
Type URI
|
tosca.nodes.WebApplication
|
5.9.5.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
context_root
|
no
|
string
|
None
|
The web application’s
context root which designates the application’s URL path within the web
server it is hosted on.
|
5.9.5.2 Definition
The TOSCA DBMS node
represents a typical relational, SQL Database Management System software
component or service.
5.9.6.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
root_password
|
no
|
string
|
None
|
The optional root password for the DBMS server.
|
|
port
|
no
|
integer
|
None
|
The DBMS server’s port.
|
5.9.6.2 Definition
The TOSCA Database
node represents a logical database that can be managed and hosted by a TOSCA DBMS node.
|
Shorthand Name
|
Database
|
|
Type Qualified Name
|
tosca:Database
|
|
Type URI
|
tosca.nodes.Database
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
name
|
yes
|
string
|
None
|
The logical database Name
|
|
port
|
no
|
integer
|
None
|
The port the database service will use to listen for
incoming data and requests.
|
|
user
|
no
|
string
|
None
|
The special user account used for database administration.
|
|
password
|
no
|
string
|
None
|
The password associated with the user account provided in
the ‘user’ property.
|
|
tosca.nodes.Database:
derived_from: tosca.nodes.Root
properties:
name:
type: string
description: the logical
name of the database
port:
type: integer
description: the port the
underlying database service will listen to for data
user:
type: string
description: the optional
user account name for DB administration
required: false
password:
type: string
description: the optional
password for the DB user account
required: false
requirements:
- host:
capability: tosca.capabilities.Container
node: tosca.nodes.DBMS
relationship: tosca.relationships.HostedOn
capabilities:
database_endpoint:
type: tosca.capabilities.Endpoint.Database
|
The TOSCA ObjectStorage
node represents storage that provides the ability to store data as objects (or
BLOBs of data) without consideration for the underlying filesystem or devices.
|
Shorthand Name
|
ObjectStorage
|
|
Type Qualified Name
|
tosca:ObjectStorage
|
|
Type URI
|
tosca.nodes.Storage.ObjectStorage
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
name
|
yes
|
string
|
None
|
The logical name of the object store (or container).
|
|
size
|
no
|
scalar-unit.size
|
greater_or_equal:
0 GB
|
The requested initial storage size (default unit is in
Gigabytes).
|
|
maxsize
|
no
|
scalar-unit.size
|
greater_or_equal:
0 GB
|
The requested maximum storage size (default unit is in
Gigabytes).
|
5.9.8.3 Notes:
·
Subclasses of the tosca.nodes.ObjectStorage
node type may impose further constraints on properties. For example, a
subclass may constrain the (minimum or maximum) length of the ‘name’ property or include a regular
expression to constrain allowed characters used in the ‘name’ property.
The TOSCA BlockStorage
node currently represents a server-local block storage device (i.e., not
shared) offering evenly sized blocks of data from which raw storage volumes can
be created.
Note: In this draft of the TOSCA Simple
Profile, distributed or Network Attached Storage (NAS) are not yet considered
(nor are clustered file systems), but the TC plans to do so in future drafts.
|
Shorthand Name
|
BlockStorage
|
|
Type Qualified Name
|
tosca:BlockStorage
|
|
Type URI
|
tosca.nodes.Storage.BlockStorage
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
size
|
yes *
|
scalar-unit.size
|
greater_or_equal:
1 MB
|
The requested storage size (default unit is MB).
* Note:
·
Required when an existing volume (i.e., volume_id) is
not available.
·
If volume_id is
provided, size is ignored. Resize of existing volumes is not considered at
this time.
|
|
volume_id
|
no
|
string
|
None
|
ID of an existing volume (that is in the accessible scope
of the requesting application).
|
|
snapshot_id
|
no
|
string
|
None
|
Some identifier that represents an existing snapshot that
should be used when creating the block storage (volume).
|
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
5.9.9.3 Definition
5.9.9.4 Additional Requirements
·
The size property is
required when an existing volume (i.e., volume_id)
is not available. However, if the property volume_id
is provided, the size property is
ignored.
5.9.9.5 Notes
·
Resize is of existing volumes is not considered at this time.
·
It is assumed that the volume contains a single filesystem that
the operating system (that is hosting an associate application) can recognize
and mount without additional information (i.e., it is operating system
independent).
·
Currently, this version of the Simple Profile does not consider
regions (or availability zones) when modeling storage.
The TOSCA Container
Runtime node represents operating system-level virtualization technology used
to run multiple application services on a single Compute host.
|
Shorthand Name
|
Container.Runtime
|
|
Type Qualified Name
|
tosca:Container.Runtime
|
|
Type URI
|
tosca.nodes.Container.Runtime
|
5.9.10.1 Definition
The TOSCA Container
Application node represents an application that requires Container-level virtualization technology.
|
Shorthand Name
|
Container.Application
|
|
Type Qualified Name
|
tosca:Container.Application
|
|
Type URI
|
tosca.nodes.Container.Application
|
5.9.11.1 Definition
5.9.12 tosca.nodes.LoadBalancer
The TOSCA Load
Balancer node represents logical function that be used in conjunction
with a Floating Address to distribute an application’s traffic (load) across a
number of instances of the application (e.g., for a clustered or scaled
application).
|
Shorthand Name
|
LoadBalancer
|
|
Type Qualified Name
|
tosca:LoadBalancer
|
|
Type URI
|
tosca.nodes.LoadBalancer
|
5.9.12.1 Definition
5.9.12.2 Notes:
·
A LoadBalancer node can
still be instantiated and managed independently of any applications it would
serve; therefore, the load balancer’s application
requirement allows for zero occurrences.
TOSCA Group Types represent logical groupings of TOSCA nodes
that have an implied membership relationship and may need to be orchestrated or
managed together to achieve some result. Some use cases being developed by the
TOSCA TC use groups to apply TOSCA policies for software placement and scaling
while other use cases show groups can be used to describe cluster
relationships.
Note: Additional normative TOSCA Group Types and use
cases for them will be developed in future drafts of this specification.
This is the default (root) TOSCA Group Type definition that all other
TOSCA base Group Types derive from.
5.10.1.1 Definition
5.10.1.2 Notes:
·
Group operations are not necessarily tied directly to member
nodes that are part of a group.
·
Future versions of this specification will create sub types of
the tosca.groups.Root type that will
describe how Group Type operations are to be orchestrated.
TOSCA Policy Types represent logical grouping of TOSCA nodes
that have an implied relationship and need to be orchestrated or managed
together to achieve some result. Some use cases being developed by the TOSCA
TC use groups to apply TOSCA policies for software placement and scaling while
other use cases show groups can be used to describe cluster relationships.
This is the default (root) TOSCA Policy Type
definition that all other TOSCA base Policy Types derive from.
5.11.1.1 Definition
|
tosca.policies.Root:
description: The TOSCA Policy
Type all other TOSCA Policy Types derive from
|
This is the default (root) TOSCA Policy Type definition
that is used to govern placement of TOSCA nodes or groups of nodes.
5.11.2.1 Definition
|
tosca.policies.Placement:
derived_from: tosca.policies.Root
description: The TOSCA Policy
Type definition that is used to govern placement of TOSCA nodes or groups of
nodes.
|
This is the default (root) TOSCA Policy Type
definition that is used to govern scaling of TOSCA nodes or groups of nodes.
5.11.3.1 Definition
|
tosca.policies.Scaling:
derived_from: tosca.policies.Root
description: The TOSCA Policy
Type definition that is used to govern scaling of TOSCA nodes or groups of
nodes.
|
This is the default (root) TOSCA Policy Type
definition that is used to govern update of TOSCA nodes or groups of nodes.
5.11.4.1 Definition
|
tosca.policies.Update:
derived_from: tosca.policies.Root
description: The TOSCA Policy
Type definition that is used to govern update of TOSCA nodes or groups of
nodes.
|
This is the default (root) TOSCA Policy Type
definition that is used to declare performance requirements for TOSCA nodes or
groups of nodes.
5.11.5.1 Definition
|
tosca.policies.Performance:
derived_from: tosca.policies.Root
description: The TOSCA Policy
Type definition that is used to declare performance requirements for TOSCA
nodes or groups of nodes.
|
Except for the examples, this section is normative
and defines changes to the TOSCA archive format relative to the TOSCA v1.0 XML
specification.
TOSCA Simple Profile definitions along with all accompanying
artifacts (e.g. scripts, binaries, configuration files) can be packaged
together in a CSAR file as already defined in the TOSCA version 1.0
specification [TOSCA-1.0]. In contrast to the TOSCA
1.0 CSAR file specification (see chapter 16 in [TOSCA-1.0]),
this simple profile makes a few simplifications both in terms of overall CSAR
file structure as well as meta-file content as described below.
A CSAR zip file is required to contain one of the
following:
·
a TOSCA-Metadata
directory, which in turn contains the TOSCA.meta
metadata file that provides entry information for a TOSCA orchestrator
processing the CSAR file.
·
a yaml (.yml or .yaml) file at the root of the archive. The yaml
file being a valid tosca definition template that MUST define a metadata
section where template_name and template_version are required.
The CSAR file may contain other directories with arbitrary
names and contents. Note that in contrast to the TOSCA 1.0 specification, it is
not required to put TOSCA definitions files into a special “Definitions”
directory, but definitions YAML files can be placed into any directory within
the CSAR file.
The TOSCA.meta
file structure follows the exact same syntax as defined in the TOSCA 1.0
specification. However, it is only required to include block_0 (see
section 16.2 in [TOSCA-1.0]) with the Entry-Definitions keyword pointing to a
valid TOSCA definitions YAML file that a TOSCA orchestrator should use as entry
for parsing the contents of the overall CSAR file.
Note that it is not required to explicitly list
TOSCA definitions files in subsequent blocks of the TOSCA.meta file, but any TOSCA definitions files besides
the one denoted by the Entry-Definitions
keyword can be found by a TOSCA orchestrator by processing respective imports statements in the entry
definitions file (or in recursively imported files).
Note also that any additional artifact files (e.g.
scripts, binaries, configuration files) do not have to be declared explicitly
through blocks in the TOSCA.meta
file. Instead, such artifacts will be fully described and pointed to by
relative path names through artifact definitions in one of the TOSCA
definitions files contained in the CSAR.
Due to the simplified structure of the CSAR file and TOSCA.meta file compared to TOSCA 1.0,
the CSAR-Version keyword
listed in block_0 of the meta-file is required to denote version 1.1.
The following listing represents a valid TOSCA.meta file according to this TOSCA
Simple Profile specification.
|
TOSCA-Meta-File-Version: 1.0
CSAR-Version: 1.1
Created-By: OASIS TOSCA TC
Entry-Definitions:
definitions/tosca_elk.yaml
|
This TOSCA.meta
file indicates its simplified TOSCA Simple Profile structure by means of the CSAR-Version keyword with value 1.1. The Entry-Definitions keyword points to a TOSCA definitions
YAML file with the name tosca_elk.yaml
which is contained in a directory called definitions
within the root of the CSAR file.
In case the archive doesn’t contains a TOSCA-Metadata
directory the archive is required to contains a single YAML file at the root of
the archive (other templates may exits in sub-directories).
This file must be a valid TOSCA definitions YAML file with
the additional restriction that the metadata section (as defined in 3.9.3.2) is
required and template_name and template_version metadata are also required.
TOSCA processors should recognized this file as
being the CSAR Entry-Definitions file. The CSAR-Version is defined by the
template_version metadata section. The Created-By value is defined by the
template_author metadata.
The following represents a valid TOSCA template file
acting as the CSAR Entry-Definitions file in an archive without TOSCA-Metadata
directory.
|
tosca_definitions_version:
tosca_simple_yaml_1_1
metadata:
template_name: my_template
template_author: OASIS TOSCA TC
template_version: 1.0
|
TOSCA defines two different kinds of workflows that can be
used to deploy (instantiate and start), manage at runtime or undeploy (stop and
delete) a TOSCA topology: declarative workflows and imperative workflows.
Declarative workflows are automatically generated by the TOSCA orchestrator
based on the nodes, relationships, and groups defined in the topology.
Imperative workflows are manually specified by the author of the topology and
allows the specification of any use-case that has not been planned in the
definition of node and relationships types or for advanced use-case (including
reuse of existing scripts and workflows).
Workflows can be triggered on deployment of a topology
(deploy workflow) on undeployment (undeploy workflow) or during runtime,
manually, or automatically based on policies defined for the topology.
Note: The TOSCA orchestrators will execute a single
workflow at a time on a topology to guarantee that the defined workflow can be
consistent and behave as expected.
TOSCA defines several normative workflows that are
used to operate a Topology. That is, reserved names of workflows that should be
preserved by TOSCA orchestrators and that, if specified in the topology will
override the workflow generated by the orchestrator :
·
deploy: is the workflow used to
instantiate and perform the initial deployment of the topology.
·
undeploy: is the workflow used to
remove all instances of a topology.
Future versions of the specification will describe
the normative naming and declarative generation of additional workflows used to
operate the topology at runtime.
·
scaling workflows: defined for every
scalable nodes or based on scaling policies
·
auto-healing workflows: defined in
order to restart nodes that may have failed
Declarative workflows are the result of the weaving of
topology’s node, relationships, and groups workflows.
The weaving process generates the workflow of every
single node in the topology, insert operations from the relationships and
groups and finally add ordering consideration. The weaving process will also
take care of the specific lifecycle of some nodes and the TOSCA orchestrator is
responsible to trigger errors or warnings in case the weaving cannot be
processed or lead to cycles for example.
This section aims to describe and explain how a TOSCA
orchestrator will generate a workflow based on the topology entities (nodes,
relationships and groups).
This section details specific constraints and considerations
that applies during the weaving process.
7.2.1.1 Orchestrator provided nodes lifecycle and weaving
When a node is abstract the orchestrator is responsible for
providing a valid matching resources for the node in order to deploy the
topology. This consideration is also valid for dangling requirements (as they
represents a quick way to define an actual node).
The lifecycle of such nodes is the responsibility of the
orchestrator and they may not answer to the normative TOSCA lifecycle. Their
workflow is considered as "delegate" and acts as a black-box between
the initial and started state in the install workflow and the started to
deleted states in the uninstall workflow.
If a relationship to some of this node defines
operations or lifecycle dependency constraint that relies on intermediate
states, the weaving SHOULD fail and the orchestrator SHOULD raise an error.
This section explains how relationships impacts the workflow
generation to enable the composition of complex topologies.
7.2.2.1 tosca.relationships.DependsOn
The depends on relationship is used to establish a
dependency from a node to another. A source node that depends on a target node
will be created only after the other entity has been started.
7.2.2.2 Note
DependsOn relationship SHOULD not be implemented. Even if
the Configure interface can be implemented this is not considered as a
best-practice. If you need specific implementation, please have a look at the
ConnectsTo relationship.
7.2.2.2.1 Example DependsOn
This example show the usage of a generic DependsOn
relationship between two custom software components.
In this example the relationship configure interface
doesn’t define operations so they don’t appear in the generated lifecycle.
7.2.2.3 tosca.relationships.ConnectsTo
The connects to relationship is similar to the
DependsOn relationship except that it is intended to provide an implementation.
The difference is more theoretical than practical but helps users to make an
actual distinction from a meaning perspective.
7.2.2.4 tosca.relationships.HostedOn
The hosted_on dependency relationship allows to define a
hosting relationship between an entity and another. The hosting relationship
has multiple impacts on the workflow and execution:
·
The implementation artifacts of the source node is executed on
the same host as the one of the target node.
·
The create operation of the source node is executed only once the
target node reach the started state.
·
When multiple nodes are hosted on the same host node, the defined
operations will not be executed concurrently even if the theoretical workflow
could allow it (actual generated workflow will avoid concurrency).
7.2.2.4.1 Example Software Component HostedOn Compute
This example explain the TOSCA weaving operation of a custom
SoftwareComponent on a tosca.nodes.Compute instance. The compute node is an
orchestrator provided node meaning that it’s lifecycle is delegated to the
orchestrator. This is a black-box and we just expect a started compute node to
be provided by the orchestrator.
The software node lifecycle operations will be executed on
the Compute node (host) instance.
7.2.2.4.2 Example Software Component HostedOn Software Component
Tosca allows some more complex hosting scenarios where a
software component could be hosted on another software component.
In such scenarios the software create operation is
triggered only once the software_base node has reached the started state.
7.2.2.4.3 Example 2 Software Components HostedOn Compute
This example illustrate concurrency constraint
introduced by the management of multiple nodes on a single compute.
7.2.3.1 Hosted nodes concurrency
TOSCA implementation currently does not allow concurrent
executions of scripts implementation artifacts (shell, python, ansible, puppet,
chef etc.) on a given host. This limitation is not applied on multiple hosts.
This limitation is expressed through the HostedOn relationship limitation
expressing that when multiple components are hosted on a given host node then their
operations will not be performed concurrently (generated workflow will ensure
that operations are not concurrent).
7.2.3.2 Dependent nodes concurrency
When a node depends on another node no operations will be
processed concurrently. In some situations, especially when the two nodes lies
on different hosts we could expect the create operation to be executed
concurrently for performance optimization purpose. The current version of the
specification will allow to use imperative workflows to solve this use-case. However,
this scenario is one of the scenario that we want to improve and handle in the
future through declarative workflows.
7.2.3.3 Target operations and get_attribute on source
The current ConnectsTo workflow implies that the target node
is started before the source node is even created. This means that
pre_configure_target and post_configure_target operations cannot use any input
based on source attribute. It is however possible to refer to get_property
inputs based on source properties. For advanced configurations the add_source
operation should be used.
Note also that future plans on declarative workflows
improvements aims to solve this kind of issues while it is currently possible
to use imperative workflows.
Imperative workflows are user defined and can define any
really specific constraints and ordering of activities. They are really
flexible and powerful and can be used for any complex use-case that cannot be
solved in declarative workflows. However, they provide less reusability as they
are defined for a specific topology rather than being dynamically generated
based on the topology content.
Imperative workflow grammar defines two ways to
define the sequence of operations in an imperative workflow:
·
Leverage the on_success
definition to define the next steps that will be executed in parallel.
·
Leverage a sequence of activity in a step.
7.3.1.1 Using on_success to define steps ordering
The graph of workflow steps is build based on the
values of on_success elements of the
various defined steps. The graph is built based on the following rules:
·
All steps that defines an on_success
operation must be executed before the next step can be executed. So if A and C
defines an on_success operation to B, then
B will be executed only when both A and C have been successfully executed.
·
The multiple nodes defined by an on_success construct can be executed in
parallel.
·
Every step that doesn’t have any predecessor is considered as an
initial step and can run in parallel.
·
Every step that doesn’t define any successor is considered as
final. When all the final nodes executions are completed then the workflow is
considered as completed.
7.3.1.1.1 Example
The following example defines multiple steps and the on_success relationship between them.
|
topology_template:
workflows:
deploy:
description: Workflow to
deploy the application
steps:
A:
on_success:
- B
- C
B:
on_success:
- D
C:
on_success:
- D
D:
E:
on_success:
- C
- F
F:
|
The following schema is the visualization of the
above definition in term of sequencing of the steps.
7.3.1.2 Define a sequence of activity on the same element
The step definition of a TOSCA imperative workflow
allows multiple activities to be defined :
|
workflows:
my_workflow:
steps:
create_my_node:
target: my_node
activities:
- set_state: creating
- call_operation:
tosca.interfaces.node.lifecycle.Standard.create
- set_state: created
|
The sequence defined here defines three different activities
that will be performed in a sequential way. This is just equivalent to writing
multiple steps chained by an on_success together :
|
workflows:
my_workflow:
steps:
creating_my_node:
target: my_node
activities:
- set_state: creating
on_success:
create_my_node
create_my_node:
target: my_node
activities:
- call_operation:
tosca.interfaces.node.lifecycle.Standard.create
on_success:
created_my_node
created_my_node:
target: my_node
activities:
- set_state: created
|
In both situations the resulting workflow is a
sequence of activities:
Imperative workflow allow user to define custom workflows
allowing them to add operations that are not normative, or for example, to
execute some operations in parallel when TOSCA would have performed sequential
execution.
As Imperative workflows are related to a topology, adding a
workflow is as simple as adding a workflows section to your topology template
and specifying the workflow and the steps that compose it.
7.3.2.1 Example: Adding a non-normative custom workflow
This sample topology add a very simple custom
workflow to trigger the mysql backup operation.
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
mysql:
type: tosca.nodes.DBMS.MySQL
requirements:
- host: my_server
interfaces:
tosca.interfaces.nodes.custom.Backup:
operations:
backup: backup.sh
workflows:
backup:
description: Performs a
snapshot of the MySQL data.
steps:
my_step:
target: mysql
activities:
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
|
In such topology the TOSCA container will still use
declarative workflow to generate the deploy and undeploy workflows as they are
not specified and a backup workflow will be available for user to trigger.
7.3.2.2 Example: Creating two nodes hosted on the same compute in parallel
TOSCA declarative workflow generation constraint the
workflow so that no operations are called in parallel on the same host. Looking
at the following topology this means that the mysql and tomcat nodes will not
be created in parallel but sequentially. This is fine in most of the situations
as packet managers like apt or yum doesn’t not support concurrency, however if
both create operations performs a download of zip package from a server most of
people will hope to do that in parallel in order to optimize throughput.
Imperative workflows can help to solve this issue.
Based on the above topology we will design a workflow that will create tomcat
and mysql in parallel but we will also ensure that tomcat is started after
mysql is started even if no relationship is defined between the components:
To achieve such workflow, the following topology
will be defined:
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
mysql:
type: tosca.nodes.DBMS.MySQL
requirements:
- host: my_server
tomcat:
type:
tosca.nodes.WebServer.Tomcat
requirements:
- host: my_server
workflows:
deploy:
description: Override the
TOSCA declarative workflow with the following.
steps:
compute_install
target: my_server
activities:
- delegate: deploy
on_success:
- mysql_install
- tomcat_install
tomcat_install:
target: tomcat
activities:
- set_state: creating
- call_operation: tosca.interfaces.node.lifecycle.Standard.create
- set_state: created
on_success:
- tomcat_starting
mysql_install:
target: mysql
activities:
- set_state: creating
- call_operation: tosca.interfaces.node.lifecycle.Standard.create
- set_state: created
- set_state: starting
- call_operation: tosca.interfaces.node.lifecycle.Standard.start
- set_state: started
on_success:
- tomcat_starting
tomcat_starting:
target: tomcat
activities:
- set_state: starting
- call_operation: tosca.interfaces.node.lifecycle.Standard.start
- set_state: started
|
Pre conditions allows the TOSCA orchestrator to determine if
a workflow can be executed based on the states and attribute values of the
topology’s node. Preconditions must be added to the initial workflow.
7.3.3.1 Example : adding precondition to custom backup workflow
In this example we will use precondition so that we
make sure that the mysql node is in the correct state for a backup.
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
mysql:
type: tosca.nodes.DBMS.MySQL
requirements:
- host: my_server
interfaces:
tosca.interfaces.nodes.custom.Backup:
operations:
backup: backup.sh
workflows:
backup:
description: Performs a
snapshot of the MySQL data.
preconditions:
- target: my_server
condition:
- assert:
- state: [{equal:
available}]
- target: mysql
condition:
- assert:
- state:
[{valid_values: [started, available]}]
- my_attribute: [{equal:
ready }]
steps:
my_step:
target: mysql
activities:
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
|
When the backup workflow will be triggered (by user
or policy) the TOSCA engine will first check that preconditions are fulfilled.
In this situation the engine will check that my_server node is in available
state AND that mysql node is in started OR available
states AND that mysql my_attribute value is equal to ready.
TOSCA allows the reusability of a workflow in other
workflows. Such concepts can be achieved thanks to the inline activity.
7.3.4.1 Reusing a workflow to build multiple workflows
The following example show how a workflow can inline
an existing workflow and reuse it.
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
mysql:
type: tosca.nodes.DBMS.MySQL
requirements:
- host: my_server
interfaces:
tosca.interfaces.nodes.custom.Backup:
operations:
backup: backup.sh
workflows:
start_mysql:
steps:
start_mysql:
target: mysql
activities :
- set_state: starting
- call_operation:
tosca.interfaces.node.lifecycle.Standard.start
- set_state: started
stop_mysql:
steps:
stop_mysql:
target: mysql
activities:
- set_state: stopping
- call_operation:
tosca.interfaces.node.lifecycle.Standard.stop
- set_state: stopped
backup:
description: Performs a
snapshot of the MySQL data.
preconditions:
- target: my_server
condition:
- assert:
- state: [{equal:
available}]
- target: mysql
condition:
- assert:
- state:
[{valid_values: [started, available]}]
- my_attribute: [{equal:
ready }]
steps:
backup_step:
activities:
- inline: stop
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
- inline: start
restart:
steps:
backup_step:
activities:
- inline: stop
- inline: start
|
The example above defines three workflows and show
how the start_mysql and stop_mysql workflows are reused in the backup and
restart workflows.
Inlined workflows are inlined sequentially in the
existing workflow for example the backup workflow would look like this:
7.3.4.2 Inlining a complex workflow
It is possible of course to inline more complex
workflows. The following example defines an inlined workflows with multiple
steps including concurrent steps:
|
topology_template:
workflows:
inlined_wf:
steps:
A:
target: node_a
activities:
- call_operation: a
on_success:
- B
- C
B:
target: node_a
activities:
- call_operation: b
on_success:
- D
C:
target: node_a
activities:
- call_operation: c
on_success:
- D
D:
target: node_a
activities:
- call_operation: d
E:
target: node_a
activities:
- call_operation: e
on_success:
- C
- F
F:
target: node_a
activities:
- call_operation: f
main_workflow:
steps:
G:
target: node_a
activities:
- set_state: initial
- inline: inlined_wf
- set_state: available
|
To describe the following workflow:
Preconditions are used to validate if the workflow should be
executed only for the initial workflow. If a workflow that is inlined defines
some preconditions theses preconditions will be used at the instance level to
define if the operations should be executed or not on the defined instance.
This construct can be used to filter some steps on a
specific instance or under some specific circumstances or topology state.
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
cluster:
type:
tosca.nodes.DBMS.Cluster
requirements:
- host: my_server
interfaces:
tosca.interfaces.nodes.custom.Backup:
operations:
backup: backup.sh
workflows:
backup:
description: Performs a
snapshot of the MySQL data.
preconditions:
- target: my_server
condition:
- assert:
- state: [{equal:
available}]
- target: mysql
condition:
- assert:
- state:
[{valid_values: [started, available]}]
- my_attribute: [{equal:
ready }]
steps:
backup_step:
target: cluster
filter: # filter is a
list of clauses. Matching between clauses is and.
- or: # only one of
sub-clauses must be true.
- assert:
- foo: [{equals:
true}]
- assert:
- bar:
[{greater_than: 2}, {less_than: 20}]
activities:
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
|
Inputs can be defined in a workflow and will be provided in
the execution context of the workflow. If an operation defines a get_input
function on one of its parameter the input will be retrieved from the workflow
input, and if not found from the topology inputs.
Workflow inputs will never be configured from policy
triggered workflows and SHOULD be used only for user triggered workflows. Of
course operations can still refer to topology inputs or template properties or
attributes even in the context of a policy triggered workflow.
7.3.6.1 Example
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
mysql:
type: tosca.nodes.DBMS.MySQL
requirements:
- host: my_server
interfaces:
tosca.interfaces.nodes.custom.Backup:
operations:
backup:
implementation:
backup.sh
inputs:
storage_url: {
get_input: storage_url }
workflows:
backup:
description: Performs a
snapshot of the MySQL data.
preconditions:
- target: my_server
valid_states:
[available]
- target: mysql
valid_states: [started,
available]
attributes:
my_attribute: [ready]
inputs:
storage_url:
type: string
steps:
my_step:
target: mysql
activities:
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
|
To trigger such a workflow, the TOSCA engine must
allow user to provide inputs that match the given definitions.
By default, failure of any activity of the workflow will
result in the failure of the workflow and will results in stopping the steps to
be executed.
Exception: uninstall workflow operation failure SHOULD not
prevent the other operations of the workflow to run (a failure in an uninstall
script SHOULD not prevent from releasing resources from the cloud).
For any workflow other than install and uninstall failures
may leave the topology in an unknown state. In such situation the TOSCA engine
may not be able to orchestrate the deployment. Implementation of on_failure construct allows to execute
rollback operations and reset the state of the affected entities back to an
orchestrator known state.
7.3.7.1 Example
|
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
mysql:
type: tosca.nodes.DBMS.MySQL
requirements:
- host: my_server
interfaces:
tosca.interfaces.nodes.custom.Backup:
operations:
backup:
implementation:
backup.sh
inputs:
storage_url: {
get_input: storage_url }
workflows:
backup:
steps:
backup_step:
target: mysql
activities:
- set_state:
backing_up # this state is not a TOSCA known state
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
- set_state: available
# this state is known by TOSCA orchestrator
on_failure:
- rollback_step
rollback_step:
target: mysql
activities:
- call_operation:
tosca.interfaces.nodes.custom.Backup.backup
- set_state: available
# this state is known by TOSCA orchestrator
|
TOSCA simple profile 1.1 version provides the genericity and
reusability of declarative workflows that is designed to address most of
use-cases and the flexibility of imperative workflows to address more complex
or specific use-cases.
Each approach has some pros and cons and we are working so
that the next versions of the specification can improve the workflow usages to
try to allow more flexibility in a more generic way. Two non-exclusive leads
are currently being discussed within the working group and may be included in
the future versions of the specification.
·
Improvement of the declarative workflows in order to allow people
to extend the weaving logic of TOSCA to fit some specific need.
·
Improvement of the imperative workflows in order to allow partial
imperative workflows to be automatically included in declarative workflows
based on specific constraints on the topology elements.
Implementation of the improvements will be done by adding
some elements to the specification and will not break compatibility with the
current specification.
7.4.1.1 Notes
·
The weaving improvement section is a Work in Progress and is not
final in 1.1 version. The elements in this section are incomplete and may be
subject to change in next specification version.
·
Moreover, the weaving improvements is one of the track of
improvements. As describe improving the reusability of imperative workflow is
another track (that may both co-exists in next specifications).
Making declarative better experimental option.
7.4.2.1 Node lifecycle definition
Node workflow is defined at the node type level. The node
workflow definition is used to generate the declarative workflow of a given
node.
The tosca.nodes.Root type defines workflow steps for
both the install workflow (used to instantiate or deploy a topology) and the
uninstall workflow (used to destroy or undeploy a topology). The workflow is
defined as follows:
|
node_types:
tosca.nodes.Root:
workflows:
install:
steps:
install_sequence:
activities:
- set_state:
creating
- call_operation:
tosca.interfaces.node.lifecycle.Standard.create
- set_state: created
- set_state:
configuring
- call_operation:
tosca.interfaces.node.lifecycle.Standard.configure
- set_state:
configured
- set_state:
starting
- call_operation:
tosca.interfaces.node.lifecycle.Standard.start
- set_state: started
uninstall:
steps:
uninstall_sequence:
activities:
- set_state:
stopping
- call_operation:
tosca.interfaces.node.lifecycle.Standard.stop
- set_state: stopped
- set_state:
deleting
- call_operation:
tosca.interfaces.node.lifecycle.Standard.delete
- set_state: deleted
|
7.4.2.2 Relationship lifecycle and weaving
While the workflow of a single node is quite simple the
TOSCA weaving process is the real key element of declarative workflows. The
process of weaving consist of the ability to create complex management
workflows including dependency management in execution order between node
operations, injection of operations to process specific instruction related to
the connection to other nodes based the relationships and groups defined in a
topology.
This section describes the relationship weaving and
how the description at a template level can be translated on an instance level.
|
relationship_types:
tosca.relationships.ConnectsTo:
workflow:
install: # name of the
workflow for wich the weaving has to be taken in account
source_weaving: # Instruct
how to weave some tasks on the source workflow (executed on SOURCE instance)
- after: configuring #
instruct that this operation should be weaved after the target reach
configuring state
wait_target: created #
add a join from a state of the target
activity:
tosca.interfaces.relationships.Configure.pre_configure_source
- before: configured #
instruct that this operation should be weaved before the target reach
configured state
activity:
tosca.interfaces.relationships.Configure.post_configure_source
- before: starting
wait_target: started #
add a join from a state of the target
- after: started
activity:
tosca.interfaces.relationships.Configure.add_target
target_weaving: # Instruct
how to weave some tasks on the target workflow (executed on TARGET instance)
- after: configuring #
instruct that this operation should be weaved after the target reach
configuring state
after_source: created
# add a join from a state of the source
activity: tosca.interfaces.relationships.Configure.pre_configure_target
- before: configured #
instruct that this operation should be weaved before the target reach
configured state
activity:
tosca.interfaces.relationships.Configure.post_configure_target
- after: started
activity:
tosca.interfaces.relationships.Configure.add_source
|
Except for the examples, this section is normative
and describes how to express and control the application centric network
semantics available in TOSCA.
TOSCA Service Templates are application centric in
the sense that they focus on describing application components in terms of
their requirements and interrelationships. In order to provide cloud
portability, it is important that a TOSCA Service Template avoid cloud specific
requirements and details. However, at the same time, TOSCA must provide the
expressiveness to control the mapping of software component connectivity to the
network constructs of the hosting cloud.
TOSCA Networking takes the following approach.
1. The
application component connectivity semantics and expressed in terms of
Requirements and Capabilities and the relationships between these. Service
Template authors are able to express the interconnectivity requirements of
their software components in an abstract, declarative, and thus highly portable
manner.
2. The
information provided in TOSCA is complete enough for a TOSCA implementation to
fulfill the application component network requirements declaratively (i.e., it
contains information such as communication initiation and layer 4 port
specifications) so that the required network semantics can be realized on
arbitrary network infrastructures.
3. TOSCA
Networking provides full control of the mapping of software component
interconnectivity to the networking constructs of the hosting cloud network
independently of the Service Template, providing the required separation
between application and network semantics to preserve Service Template
portability.
4. Service
Template authors have the choice of specifying application component networking
requirements in the Service Template or completely separating the application
component to network mapping into a separate document. This allows application
components with explicit network requirements to express them while allowing
users to control the complete mapping for all software components which may not
have specific requirements. Usage of these two approaches is possible
simultaneously and required to avoid having to re-write components network
semantics as arbitrary sets of components are assembled into Service Templates.
5. Defining a
set of network semantics which are expressive enough to address the most common
application connectivity requirements while avoiding dependencies on specific
network technologies and constructs. Service Template authors and cloud
providers are able to express unique/non-portable semantics by defining their
own specialized network Requirements and Capabilities.
TOSCA’s application centric approach includes the modeling
of network connectivity semantics from an application component connectivity
perspective. The basic premise is that applications contain components which
need to communicate with other components using one or more endpoints over a
network stack such as TCP/IP, where connectivity between two components is
expressed as a <source component, source address, source port, target
component, target address, target port> tuple. Note that source and target
components are added to the traditional 4 tuple to provide the application
centric information, mapping the network to the source or target component
involved in the connectivity.
Software components are expressed as Node Types in TOSCA
which can express virtually any kind of concept in a TOSCA model. Node Types
offering network based functions can model their connectivity using a special
Endpoint Capability, tosca.capabilities.Endpoint,
designed for this purpose. Node Types which require an Endpoint can specify
this as a TOSCA requirement. A special Relationship Type,
tosca.relationships.ConnectsTo, is used to implicitly or explicitly relate the
source Node Type’s endpoint to the required endpoint in the target node type.
Since tosca.capabilities.Endpoint and tosca.relationships.ConnectsTo are TOSCA
types, they can be used in templates and extended by subclassing in the usual
ways, thus allowing the expression of additional semantics as needed.
The following diagram shows how the TOSCA node, capability and relationship
types enable modeling the application layer decoupled from the network model
intersecting at the Compute node using the
Bindable capability type.
As you can see, the Port
node type effectively acts a broker node between the Network node description
and a host Compute node of an application.
This section describes how TOSCA supports the typical
client/server and group communication semantics found in application
architectures.
The tosca.relationships.ConnectsTo expresses that
requirement that a source application component needs to be able to communicate
with a target software component to consume the services of the target.
ConnectTo is a component interdependency semantic in the most general sense and
does not try imply how the communication between the source and target
components is physically realized.
Application component intercommunication typically has
conventions regarding which component(s) initiate the communication. Connection
initiation semantics are specified in tosca.capabilities.Endpoint.
Endpoints at each end of the tosca.relationships.ConnectsTo
must indicate identical connection initiation semantics.
The following sections describe the normative connection
initiation semantics for the tosca.relationships.ConnectsTo Relationship Type.
8.3.1.1 Source to Target
The Source to Target communication initiation semantic is
the most common case where the source component initiates communication with
the target component in order to fulfill an instance of the
tosca.relationships.ConnectsTo relationship. The typical case is a “client”
component connecting to a “server” component where the client initiates a
stream oriented connection to a pre-defined transport specific port or set of
ports.
It is the responsibility of the TOSCA implementation to
ensure the source component has a suitable network path to the target component
and that the ports specified in the respective tosca.capabilities.Endpoint are not
blocked. The TOSCA implementation may only represent state of the
tosca.relationships.ConnectsTo relationship as fulfilled after the actual
network communication is enabled and the source and target components are in
their operational states.
Note that the connection initiation semantic only impacts
the fulfillment of the actual connectivity and does not impact the node
traversal order implied by the tosca.relationships.ConnectsTo Relationship
Type.
8.3.1.2 Target to Source
The Target to Source communication initiation semantic is a
less common case where the target component initiates communication with the
source comment in order to fulfill an instance of the
tosca.relationships.ConnectsTo relationship. This “reverse” connection
initiation direction is typically required due to some technical requirements
of the components or protocols involved, such as the requirement that SSH mush
only be initiated from target component in order to fulfill the services
required by the source component.
It is the responsibility of the TOSCA implementation to
ensure the source component has a suitable network path to the target component
and that the ports specified in the respective tosca.capabilities.Endpoint are
not blocked. The TOSCA implementation may only represent state of the
tosca.relationships.ConnectsTo relationship as fulfilled after the actual
network communication is enabled and the source and target components are in
their operational states.
Note that the connection initiation semantic only impacts
the fulfillment of the actual connectivity and does not impact the node
traversal order implied by the tosca.relationships.ConnectsTo Relationship
Type.
8.3.1.3 Peer-to-Peer
The Peer-to-Peer communication initiation semantic allows
any member of a group to initiate communication with any other member of the
same group at any time. This semantic typically appears in clustering and
distributed services where there is redundancy of components or services.
It is the responsibility of the TOSCA implementation to
ensure the source component has a suitable network path between all the member
component instances and that the ports specified in the respective
tosca.capabilities.Endpoint are not blocked, and the appropriate multicast
communication, if necessary, enabled. The TOSCA implementation may only
represent state of the tosca.relationships.ConnectsTo relationship as fulfilled
after the actual network communication is enabled such that at least one-member
component of the group may reach any other member component of the group.
Endpoints specifying the Peer-to-Peer initiation semantic
need not be related with a tosca.relationships.ConnectsTo relationship for the
common case where the same set of component instances must communicate with
each other.
Note that the connection initiation semantic only impacts
the fulfillment of the actual connectivity and does not impact the node
traversal order implied by the tosca.relationships.ConnectsTo Relationship
Type.
TOSCA Service Templates must express enough details about
application component intercommunication to enable TOSCA implementations to
fulfill these communication semantics in the network infrastructure. TOSCA
currently focuses on TCP/IP as this is the most pervasive in today’s cloud
infrastructures. The layer 4 ports required for application component
intercommunication are specified in tosca.capabilities.Endpoint. The union of
the port specifications of both the source and target
tosca.capabilities.Endpoint which are part of the tosca.relationships.ConnectsTo
Relationship Template are interpreted as the effective set of ports which must
be allowed in the network communication.
The meaning of Source and Target port(s) corresponds to the
direction of the respective tosca.relationships.ConnectsTo.
TOSCA orchestrators are responsible for the provisioning of
the network connectivity for declarative TOSCA Service Templates (Declarative
TOSCA Service Templates don’t contain explicit plans). This means that the
TOSCA orchestrator must be able to infer a suitable logical connectivity model
from the Service Template and then decide how to provision the logical
connectivity, referred to as “fulfillment”, on the available underlying
infrastructure. In order to enable fulfillment, sufficient technical details
still must be specified, such as the required protocols, ports and QOS
information. TOSCA connectivity types, such as tosca.capabilities.Endpoint,
provide well defined means to express these details.
TOSCA Service Templates are by default network agnostic.
TOSCA’s application centric approach only requires that a TOSCA Service
Template contain enough information for a TOSCA orchestrator to infer suitable
network connectivity to meet the needs of the application components. Thus
Service Template designers are not required to be aware of or provide specific
requirements for underlying networks. This approach yields the most portable
Service Templates, allowing them to be deployed into any infrastructure which
can provide the necessary component interconnectivity.
TOSCA provides mechanisms for providing control over network
fulfillment.
This mechanism allows the application network designer to
express in service template or network template how the networks should be
provisioned.
For the use cases described below let’s assume we have a
typical 3-tier application which is consisting of FE (frontend), BE (backend)
and DB (database) tiers. The simple application topology diagram can be shown
below:
Figure‑5: Typical 3-Tier Network
8.4.3.1 Use case: OAM Network
When deploying an application in service provider’s
on-premise cloud, it’s very common that one or more of the application’s services
should be accessible from an ad-hoc OAM (Operations, Administration and
Management) network which exists in the service provider backbone.
As an application network designer, I’d like to express in
my TOSCA network template (which corresponds to my TOSCA service template) the
network CIDR block, start ip, end ip and segmentation ID (e.g. VLAN id).
The diagram below depicts a typical 3-tiers application with
specific networking requirements for its FE tier server cluster:
8.4.3.2 Use case: Data Traffic network
The diagram below defines a set of networking requirements
for the backend and DB tiers of the 3-tier app mentioned above.
8.4.3.3 Use case: Bring my own DHCP
The same 3-tier app requires for its admin traffic network
to manage the IP allocation by its own DHCP which runs autonomously as part of
application domain.
For this purpose, the app network designer would like to
express in TOSCA that the underlying provisioned network will be set with
DHCP_ENABLED=false. See this illustrated in the figure below:
The TOSCA Network
node represents a simple, logical network service.
|
Shorthand Name
|
Network
|
|
Type Qualified Name
|
tosca:Network
|
|
Type URI
|
tosca.nodes.network.Network
|
8.5.1.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
ip_version
|
no
|
integer
|
valid_values: [4, 6]
default: 4
|
The IP version of the requested network
|
|
cidr
|
no
|
string
|
None
|
The cidr block of the requested network
|
|
start_ip
|
no
|
string
|
None
|
The IP address to be used as the 1st one in a
pool of addresses derived from the cidr block full IP range
|
|
end_ip
|
no
|
string
|
None
|
The IP address to be used as the last one in a pool of
addresses derived from the cidr block full IP range
|
|
gateway_ip
|
no
|
string
|
None
|
The gateway IP address.
|
|
network_name
|
no
|
string
|
None
|
An Identifier that represents an existing Network instance
in the underlying cloud infrastructure – OR – be used as the name of the new
created network.
·
If network_name is provided along with network_id
they will be used to uniquely identify an existing network and not creating a
new one, means all other possible properties are not allowed.
·
network_name
should be more convenient for using. But in case that network name uniqueness
is not guaranteed then one should provide a network_id as well.
|
|
network_id
|
no
|
string
|
None
|
An Identifier that represents an existing Network instance
in the underlying cloud infrastructure.
This property is mutually exclusive with all other
properties except network_name.
·
Appearance of network_id in network template
instructs the Tosca container to use an existing network instead of creating
a new one.
·
network_name
should be more convenient for using. But in case that network name uniqueness
is not guaranteed then one should add a network_id as well.
·
network_name
and network_id
can be still used together to achieve both uniqueness and convenient.
|
|
segmentation_id
|
no
|
string
|
None
|
A segmentation identifier in the underlying cloud
infrastructure (e.g., VLAN id, GRE tunnel id). If
the segmentation_id is
specified, the network_type
or physical_network properties should be provided as well.
|
|
network_type
|
no
|
string
|
None
|
Optionally, specifies the nature
of the physical network in the underlying cloud infrastructure. Examples are
flat, vlan, gre or vxlan. For flat and vlan types, physical_network should
be provided too.
|
|
physical_network
|
no
|
string
|
None
|
Optionally, identifies the
physical network on top of which the network is implemented, e.g. physnet1.
This property is required if network_type
is flat or vlan.
|
|
dhcp_enabled
|
no
|
boolean
|
default: true
|
Indicates the TOSCA container to create a virtual network
instance with or without a DHCP service.
|
8.5.1.2 Attributes
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
segmentation_id
|
no
|
string
|
None
|
The actual segmentation_id that is been assigned to
the network by the underlying cloud infrastructure.
|
8.5.1.3 Definition
|
tosca.nodes.network.Network:
derived_from: tosca.nodes.Root
properties:
ip_version:
type: integer
required: false
default: 4
constraints:
- valid_values: [ 4, 6 ]
cidr:
type: string
required: false
start_ip:
type: string
required: false
end_ip:
type: string
required: false
gateway_ip:
type: string
required: false
network_name:
type: string
required: false
network_id:
type: string
required: false
segmentation_id:
type: string
required: false
network_type:
type: string
required: false
physical_network:
type: string
required: false
capabilities:
link:
type: tosca.capabilities.network.Linkable
|
The TOSCA Port node
represents a logical entity that associates between Compute and Network
normative types.
The Port node type effectively represents a single
virtual NIC on the Compute node instance.
|
Shorthand Name
|
Port
|
|
Type Qualified Name
|
tosca:Port
|
|
Type URI
|
tosca.nodes.network.Port
|
8.5.2.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
ip_address
|
no
|
string
|
None
|
Allow the user to set a fixed IP address.
Note that this address is a request to the provider which
they will attempt to fulfill but may not be able to dependent on the network
the port is associated with.
|
|
order
|
no
|
integer
|
greater_or_equal: 0
default: 0
|
The order of the NIC on the compute instance (e.g. eth2).
Note:
when binding more than one port to a single compute (aka multi vNICs) and
ordering is desired, it is *mandatory* that all ports will be set with an
order value and. The order values must represent a positive,
arithmetic progression that starts with 0 (e.g. 0, 1, 2, …, n).
|
|
is_default
|
no
|
boolean
|
default: false
|
Set is_default=true to apply a default
gateway route on the running compute instance to the associated network
gateway.
Only one port that is associated to single compute node
can set as default=true.
|
|
ip_range_start
|
no
|
string
|
None
|
Defines the starting IP of a range to be allocated for the
compute instances that are associated by this Port.
Without setting this property the IP allocation is done
from the entire CIDR block of the network.
|
|
ip_range_end
|
no
|
string
|
None
|
Defines the ending IP of a range to be allocated for the
compute instances that are associated by this Port.
Without setting this property the IP allocation is done
from the entire CIDR block of the network.
|
8.5.2.2 Attributes
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
ip_address
|
no
|
string
|
None
|
The IP address would be assigned to the associated compute
instance.
|
8.5.2.3 Definition
A node type that includes the Linkable capability
indicates that it can be pointed to by a tosca.relationships.network.LinksTo
relationship type.
|
Shorthand Name
|
Linkable
|
|
Type Qualified Name
|
tosca:.Linkable
|
|
Type URI
|
tosca.capabilities.network.Linkable
|
8.5.3.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
8.5.3.2 Definition
This relationship type represents an association
relationship between Port and Network node types.
|
Shorthand Name
|
LinksTo
|
|
Type Qualified Name
|
tosca:LinksTo
|
|
Type URI
|
tosca.relationships.network.LinksTo
|
8.5.4.1 Definition
This type represents a network association
relationship between Port and Compute node types.
|
Shorthand Name
|
network.BindsTo
|
|
Type Qualified Name
|
tosca:BindsTo
|
|
Type URI
|
tosca.relationships.network.BindsTo
|
8.5.5.1 Definition
This approach allows someone who understands the application’s
networking requirements, mapping the details of the underlying network to the
appropriate node templates in the application.
The motivation for this approach is providing the
application network designer a fine-grained control on how networks are
provisioned and stitched to its application by the TOSCA orchestrator and
underlying cloud infrastructure while still preserving the portability of his
service template. Preserving the portability means here not doing any
modification in service template but just “plug-in” the desired network
modeling. The network modeling can reside in the same service template file but
the best practice should be placing it in a separated self-contained network
template file.
This “pluggable” network template approach introduces a new
normative node type called Port, capability called tosca.capabilities.network.Linkable
and relationship type called tosca.relationships.network.LinksTo.
The idea of the Port is to elegantly associate the desired
compute nodes with the desired network nodes while not “touching” the compute
itself.
The following diagram series demonstrate the plug-ability
strength of this approach.
Let’s assume an application designer has modeled a
service template as shown in Figure 1 that describes the application topology
nodes (compute, storage, software components, etc.) with their relationships.
The designer ideally wants to preserve this service template and use it in any
cloud provider environment without any change.
Figure‑6: Generic Service Template
When the application designer comes to consider its
application networking requirement they typically call the network
architect/designer from their company (who has the correct expertise).
The network designer, after understanding the
application connectivity requirements and optionally the target cloud provider
environment, is able to model the network template and plug it to the service
template as shown in Figure 2:
Figure‑7: Service template with network template
A
When there’s a new target cloud environment to run
the application on, the network designer is simply creates a new network
template B that corresponds to the new environmental conditions and provide it
to the application designer which packs it into the application CSAR.
Figure‑8: Service template with network template
B
The node templates for these three networks would be
defined as follows:
|
node_templates:
frontend:
type: tosca.nodes.Compute
properties: # omitted for
brevity
backend:
type: tosca.nodes.Compute
properties: # omitted for
brevity
database:
type: tosca.nodes.Compute
properties: # omitted for
brevity
oam_network:
type:
tosca.nodes.network.Network
properties: # omitted for
brevity
admin_network:
type:
tosca.nodes.network.Network
properties: # omitted for
brevity
data_network:
type:
tosca.nodes.network.Network
properties: # omitted for
brevity
# ports definition
fe_oam_net_port:
type: tosca.nodes.network.Port
properties:
is_default: true
ip_range_start: { get_input:
fe_oam_net_ip_range_start }
ip_range_end: { get_input:
fe_oam_net_ip_range_end }
requirements:
- link: oam_network
- binding: frontend
fe_admin_net_port:
type: tosca.nodes.network.Port
requirements:
- link: admin_network
- binding: frontend
be_admin_net_port:
type: tosca.nodes.network.Port
properties:
order: 0
requirements:
- link: admin_network
- binding: backend
be_data_net_port:
type: tosca.nodes.network.Port
properties:
order: 1
requirements:
- link: data_network
- binding: backend
db_data_net_port:
type: tosca.nodes.network.Port
requirements:
- link: data_network
- binding: database
|
This approach allows the Service Template designer to map an
endpoint to a logical network.
The use case shown below examines a way to express
in the TOSCA YAML service template a typical 3-tier application with their
required networking modeling:
|
node_templates:
frontend:
type: tosca.nodes.Compute
properties: # omitted for
brevity
requirements:
- network_oam: oam_network
- network_admin:
admin_network
backend:
type: tosca.nodes.Compute
properties: # omitted for
brevity
requirements:
- network_admin:
admin_network
- network_data: data_network
database:
type: tosca.nodes.Compute
properties: # omitted for
brevity
requirements:
- network_data: data_network
oam_network:
type: tosca.nodes.network.Network
properties:
ip_version: { get_input:
oam_network_ip_version }
cidr: { get_input:
oam_network_cidr }
start_ip: { get_input:
oam_network_start_ip }
end_ip: { get_input:
oam_network_end_ip }
admin_network:
type: tosca.nodes.network.Network
properties:
ip_version: { get_input:
admin_network_ip_version }
dhcp_enabled: { get_input:
admin_network_dhcp_enabled }
data_network:
type:
tosca.nodes.network.Network
properties:
ip_version: { get_input:
data_network_ip_version }
cidr: { get_input:
data_network_cidr }
|
This section defines non-normative types which are
used only in examples and use cases in this specification and are included only
for completeness for the reader. Implementations of this specification are not
required to support these types for conformance.
9.1
Artifact Types
This section contains are non-normative Artifact Types used
in use cases and examples.
This artifact represents a Docker “image” (a TOSCA
deployment artifact type) which is a binary comprised of one or more (a union
of read-only and read-write) layers created from snapshots within the
underlying Docker Union File System.
9.1.1.1 Definition
A Virtual Machine (VM) formatted as an ISO standard disk
image.
9.1.2.1 Definition
|
tosca.artifacts.Deployment.Image.VM.ISO:
derived_from: tosca.artifacts.Deployment.Image.VM
description: Virtual Machine
(VM) image in ISO disk format
mime_type:
application/octet-stream
file_ext: [ iso ]
|
A Virtual Machine (VM) formatted as a QEMU emulator version 2 standard
disk image.
9.1.3.1 Definition
|
tosca.artifacts.Deployment.Image.VM.QCOW2:
derived_from: tosca.artifacts.Deployment.Image.VM
description: Virtual Machine
(VM) image in QCOW v2 standard disk format
mime_type:
application/octet-stream
file_ext: [ qcow2 ]
|
This section contains are non-normative Capability Types
used in use cases and examples.
The type indicates capabilities of a Docker runtime
environment (client).
|
Shorthand Name
|
Container.Docker
|
|
Type Qualified Name
|
tosca:Container.Docker
|
|
Type URI
|
tosca.capabilities.Container.Docker
|
9.2.1.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
version
|
no
|
version[]
|
None
|
The Docker version capability (i.e., the versions
supported by the capability).
|
|
publish_all
|
no
|
boolean
|
default: false
|
Indicates that all ports (ranges) listed in the dockerfile
using the EXPOSE keyword be published.
|
|
publish_ports
|
no
|
list of PortSpec
|
None
|
List of ports mappings from source (Docker container) to
target (host) ports to publish.
|
|
expose_ports
|
no
|
list of PortSpec
|
None
|
List of ports mappings from source (Docker container) to
expose to other Docker containers (not accessible outside host).
|
|
volumes
|
no
|
list of string
|
None
|
The dockerfile VOLUME command which is used to
enable access from the Docker container to a directory on the host machine.
|
|
host_id
|
no
|
string
|
None
|
The optional identifier of an existing host resource that
should be used to run this container on.
|
|
volume_id
|
no
|
string
|
None
|
The optional identifier of an existing storage volume
(resource) that should be used to create the container’s mount point(s) on.
|
9.2.1.2 Definition
|
tosca.capabilities.Container.Docker:
derived_from: tosca.capabilities.Container
properties:
version:
type: list
required: false
entry_schema: version
publish_all:
type: boolean
default: false
required: false
publish_ports:
type: list
entry_schema: PortSpec
required: false
expose_ports:
type: list
entry_schema: PortSpec
required: false
volumes:
type: list
entry_schema: string
required: false
|
9.2.1.3 Notes
·
When the expose_ports
property is used, only the source
and source_range properties of PortSpec would be valid for supplying port numbers or
ranges, the target and target_range properties would be ignored.
This section contains non-normative node types referenced in
use cases and examples. All additional Attributes, Properties, Requirements
and Capabilities shown in their definitions (and are not inherited from ancestor
normative types) are also considered to be non-normative.
9.3.1 tosca.nodes.Database.MySQL
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
9.3.2.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
9.3.2.2 Definition
|
tosca.nodes.DBMS.MySQL:
derived_from: tosca.nodes.DBMS
properties:
port:
description: reflect the
default MySQL server port
default: 3306
root_password:
# MySQL requires a
root_password for configuration
# Override parent DBMS
definition to make this property required
required: true
capabilities:
# Further constrain the ‘host’
capability to only allow MySQL databases
host:
valid_source_types: [ tosca.nodes.Database.MySQL ]
|
9.3.3.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
9.3.3.2 Definition
This section defines a non-normative Node type for the
WordPress [WordPress] application.
9.3.4.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
9.3.4.2 Definition
This non-normative node type represents a Node.js [NodeJS] web application server.
9.3.5.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
9.3.5.2 Definition
|
tosca.nodes.WebServer.Nodejs:
derived_from: tosca.nodes.WebServer
properties:
# Property to supply the
desired implementation in the Github repository
github_url:
required: no
type: string
description: location of the
application on the github.
default:
https://github.com/mmm/testnode.git
interfaces:
Standard:
inputs:
github_url:
type: string
|
9.3.6.1 Properties
|
Name
|
Required
|
Type
|
Constraints
|
Description
|
|
N/A
|
N/A
|
N/A
|
N/A
|
N/A
|
9.3.6.2 Definition
This section is non-normative and includes use cases
that explore how to model components and their relationships using TOSCA Simple
Profile in YAML.
This use case examines the ways TOSCA YAML can be used to
express a simple hosting relationship (i.e., HostedOn)
using the normative TOSCA WebServer and
WebApplication node types defined in
this specification.
10.1.1.1 WebServer declares its “host” capability
For convenience, relevant parts of the normative
TOSCA Node Type for WebServer are shown
below:
As can be seen, the WebServer Node Type declares its capability
to “contain” (i.e., host) other nodes using the symbolic name “host” and providing the Capability Type tosca.capabilities.Container. It should be
noted that the symbolic name of “host”
is not a reserved word, but one assigned by the type designer that implies at
or betokens the associated capability. The Container
capability definition also includes a required list of valid Node Types that
can be contained by this, the WebServer,
Node Type. This list is declared using the keyname of valid_source_types and in this case it
includes only allowed type WebApplication.
10.1.1.2 WebApplication declares its “host” requirement
The WebApplication
node type needs to be able to describe the type of capability a target node
would have to provide in order to “host” it. The normative TOSCA capability
type tosca.capabilities.Container is used to describe all normative TOSCA
hosting (i.e., container-containee pattern) relationships. As can be seen
below, the WebApplication accomplishes this by declaring a requirement with the
symbolic name “host” with the capability
keyname set to tosca.capabilities.Container.
Again, for convenience, the relevant parts of the
normative WebApplication Node Type are shown below:
10.1.1.2.1 Notes
·
The symbolic name “host” is not a keyword and was selected for
consistent use in TOSCA normative node types to give the reader an indication
of the type of requirement being referenced. A valid HostedOn relationship
could still be established between WebApplicaton and WebServer in a TOSCA
Service Template regardless of the symbolic name assigned to either the requirement
or capability declaration.
This use case examines the ways TOSCA YAML can be used to
express a simple connection relationship (i.e., ConnectsTo) between some service
derived from the SoftwareComponent
Node Type, to the normative WebServer
node type defined in this specification.
The service template that would establish a ConnectsTo relationship as
follows:
|
node_types:
MyServiceType:
derived_from: SoftwareComponent
requirements:
# This type of service requires a connection to a WebServer’s data_endpoint
- connection1:
node: WebServer
relationship: ConnectsTo
capability: Endpoint
topology_template:
node_templates:
my_web_service:
type: MyServiceType
...
requirements:
- connection1:
node: my_web_server
my_web_server:
# Note, the normative WebServer node type declares the “data_endpoint”
# capability of type tosca.capabilities.Endpoint.
type: WebServer
|
Since the normative WebServer Node Type only declares one
capability of type tosca.capabilties.Endpoint
(or Endpoint, its shortname alias in
TOSCA) using the symbolic name data_endpoint,
the my_web_service node template does
not need to declare that symbolic name on its requirement declaration. If
however, the my_web_server node was
based upon some other node type that declared more than one capability of type Endpoint, then the capability keyname could be used to supply
the desired symbolic name if necessary.
10.1.2.1 Best practice
It should be noted that the best practice for
designing Node Types in TOSCA should not export two capabilities of the same
type if they truly offer different functionality (i.e., different capabilities)
which should be distinguished using different Capability Type definitions.
This use case examines the ways TOSCA YAML can be used to
express a simple AttachesTo relationship between a Compute node and a locally
attached BlockStorage node.
The service template that would establish an AttachesTo relationship follows:
|
node_templates:
my_server:
type: Compute
...
requirements:
# contextually this can only
be a relationship type
- local_storage:
# capability is provided by Compute Node Type
node:
my_block_storage
relationship:
type: AttachesTo
properties:
location:
/path1/path2
# This maps the local
requirement name ‘local_storage’ to the
# target node’s
capability name ‘attachment’
my_block_storage:
type: BlockStorage
properties:
size: 10 GB
|
This builds upon the previous use case (10.1.3)
to examine how a template author could attach multiple Compute nodes
(templates) to the same BlockStorage node (template), but with slightly
different property values for the AttachesTo relationship.
Specifically, several notation options are shown (in this
use case) that achieve the same desired result.
10.1.4.1 Simple Profile Rationale
Referencing an explicitly declared Relationship Template is
a convenience of the Simple Profile that allows template authors an entity to
set, constrain or override the properties and operations as defined in its
declared (Relationship) Type much as allowed now for Node Templates. It is
especially useful when a complex Relationship Type (with many configurable
properties or operations) has several logical occurrences in the same Service
(Topology) Template; allowing the author to avoid configuring these same
properties and operations in multiple Node Templates.
10.1.4.2 Notation Style #1: Augment AttachesTo Relationship Type directly
in each Node Template
This notation extends the methodology used for establishing
a HostedOn relationship, but allowing template author to supply (dynamic)
configuration and/or override of properties and operations.
Note: This option will remain valid for Simple
Profile regardless of other notation (copy or aliasing) options being discussed
or adopted for future versions.
|
node_templates:
my_block_storage:
type: BlockStorage
properties:
size: 10
my_web_app_tier_1:
type: Compute
requirements:
- local_storage:
node: my_block_storage
relationship:
MyAttachesTo
# use default property
settings in the Relationship Type definition
my_web_app_tier_2:
type: Compute
requirements:
- local_storage:
node: my_block_storage
relationship:
type: MyAttachesTo
# Override default
property setting for just the ‘location’ property
properties:
location:
/some_other_data_location
relationship_types:
MyAttachesTo:
derived_from: AttachesTo
properties:
location: /default_location
interfaces:
Configure:
post_configure_target:
implementation: default_script.sh
|
10.1.4.3 Notation Style #2: Use the ‘template’ keyword on the Node
Templates to specify which named Relationship Template to use
This option shows how to explicitly declare
different named Relationship Templates within the Service Template as part of a
relationship_templates section (which
have different property values) and can be referenced by different Compute
typed Node Templates.
|
node_templates:
my_block_storage:
type: BlockStorage
properties:
size: 10
my_web_app_tier_1:
derived_from: Compute
requirements:
- local_storage:
node: my_block_storage
relationship:
storage_attachesto_1
my_web_app_tier_2:
derived_from: Compute
requirements:
- local_storage:
node: my_block_storage
relationship:
storage_attachesto_2
relationship_templates:
storage_attachesto_1:
type: MyAttachesTo
properties:
location: /my_data_location
storage_attachesto_2:
type: MyAttachesTo
properties:
location: /some_other_data_location
relationship_types:
MyAttachesTo:
derived_from: AttachesTo
interfaces:
some_interface_name:
some_operation:
implementation: default_script.sh
|
10.1.4.4 Notation Style #3: Using the “copy” keyname to define a similar
Relationship Template
How does TOSCA make it easier to create a new relationship
template that is mostly the same as one that exists without manually copying
all the same information? TOSCA provides the copy
keyname as a convenient way to copy an existing template definition into a new
template definition as a starting point or basis for describing a new
definition and avoid manual copy. The end results are cleaner TOSCA Service
Templates that allows the description of only the changes (or deltas) between
similar templates.
The example below shows that the Relationship
Template named storage_attachesto_1
provides some overrides (conceptually a large set of overrides) on its Type
which the Relationship Template named storage_attachesto_2
wants to “copy” before perhaps
providing a smaller number of overrides.
|
node_templates:
my_block_storage:
type: BlockStorage
properties:
size: 10
my_web_app_tier_1:
derived_from: Compute
requirements:
- attachment:
node: my_block_storage
relationship:
storage_attachesto_1
my_web_app_tier_2:
derived_from: Compute
requirements:
- attachment:
node: my_block_storage
relationship:
storage_attachesto_2
relationship_templates:
storage_attachesto_1:
type: MyAttachesTo
properties:
location: /my_data_location
interfaces:
some_interface_name:
some_operation_name_1: my_script_1.sh
some_operation_name_2: my_script_2.sh
some_operation_name_3: my_script_3.sh
storage_attachesto_2:
# Copy the contents
of the “storage_attachesto_1” template into this new one
copy: storage_attachesto_1
# Then change just
the value of the location property
properties:
location: /some_other_data_location
relationship_types:
MyAttachesTo:
derived_from: AttachesTo
interfaces:
some_interface_name:
some_operation:
implementation: default_script.sh
|
11
Application Modeling Use Cases
This section is non-normative and includes use cases
that show how to model Infrastructure-as-a-Service (IaaS),
Platform-as-a-Service (PaaS) and complete application uses cases using TOSCA
Simple Profile in YAML.
Many of the use cases listed below can by found under the
following link:
https://github.com/openstack/heat-translator/tree/master/translator/tests/data
|
Name
|
Description
|
|
Compute: Create a
single Compute instance with a host Operating System
|
Introduces a TOSCA Compute node
type which is used to stand up a single compute instance with a host
Operating System Virtual Machine (VM) image selected by the platform provider
using the Compute node’s properties.
|
|
Software Component 1:
Automatic deployment of a Virtual Machine (VM) image artifact
|
Introduces the SoftwareComponent node type which declares software that is
hosted on a Compute instance. In this case, the
SoftwareComponent declares a VM image as a deployment artifact which includes
its own pre-packaged operating system and software. The TOSCA Orchestrator
detects this known deployment artifact type on the SoftwareComponent
node template and automatically deploys it to the Compute node.
|
|
BlockStorage-1:
Attaching Block Storage to a single Compute instance
|
Demonstrates how to attach a TOSCA BlockStorage node to a Compute node
using the normative AttachesTo relationship.
|
|
BlockStorage-2:
Attaching Block Storage using a custom Relationship Type
|
Demonstrates how to attach a TOSCA BlockStorage node to a Compute node
using a custom RelationshipType that derives from the normative AttachesTo relationship.
|
|
BlockStorage-3:
Using a Relationship Template of type AttachesTo
|
Demonstrates how to attach a TOSCA BlockStorage node to a Compute node
using a TOSCA Relationship Template that is based upon the normative AttachesTo Relationship Type.
|
|
BlockStorage-4:
Single Block Storage shared by 2-Tier Application with custom AttachesTo Type
and implied relationships
|
This use case shows 2 Compute instances (2 tiers) with one
BlockStorage node, and also uses a custom AttachesTo
Relationship that provides a default mount point (i.e., location)
which the 1st tier uses, but the 2nd tier provides a
different mount point.
|
|
BlockStorage-5:
Single Block Storage shared by 2-Tier Application with custom AttachesTo Type
and explicit Relationship Templates
|
This use case is like the previous BlockStorage-4 use case, but also creates
two relationship templates (one for each tier) each of which provide a
different mount point (i.e., location) which overrides the default
location defined in the custom Relationship Type.
|
|
BlockStorage-6:
Multiple Block Storage attached to different Servers
|
This use case demonstrates how two different TOSCA BlockStorage nodes can be attached to two different Compute nodes (i.e., servers) each using the
normative AttachesTo relationship.
|
|
Object Storage 1:
Creating an Object Storage service
|
Introduces the TOSCA ObjectStorage node type and shows how it can be instantiated.
|
|
Network-1: Server
bound to a new network
|
Introduces the TOSCA Network and
Port nodes used for modeling logical networks
using the LinksTo and BindsTo Relationship
Types. In this use case, the template is invoked without an existing network_name as an input property so a new network is
created using the properties declared in the Network node.
|
|
Network-2: Server
bound to an existing network
|
Shows how to use a network_name as an input parameter to the template to allow a server to be
associated with (i.e. bound to) an existing Network.
|
|
Network-3: Two
servers bound to a single network
|
This use case shows how two servers (Compute nodes) can be associated with the same Network node using two logical network Ports.
|
|
Network-4: Server
bound to three networks
|
This use case shows how three logical networks (Network nodes),
each with its own IP address range, can be associated with the same server (Compute
node).
|
|
WebServer-DBMS-1:
WordPress [WordPress] + MySQL, single instance
|
Shows how to host a TOSCA WebServer
with a TOSCA
WebApplication,
DBMS and Database Node
Types along with their dependent HostedOn and
ConnectsTo relationships.
|
|
WebServer-DBMS-2:
Nodejs with PayPal Sample App and MongoDB on separate instances
|
Instantiates a 2-tier application with Nodejs
and its (PayPal sample) WebApplication on one tier which
connects a MongoDB database (which stores its application data) using a ConnectsTo
relationship.
|
|
Multi-Tier-1:
Elasticsearch, Logstash, Kibana (ELK)
|
Shows Elasticsearch, Logstash
and Kibana (ELK) being used in a typical manner to
collect, search and monitor/visualize data from a running application.
This use case builds upon the previous Nodejs/MongoDB 2-tier application as the one being
monitored. The collectd and rsyslog components
are added to both the WebServer and Database tiers which work to collect data
for Logstash.
In addition to the application tiers, a 3rd
tier is introduced with Logstash
to collect data from the application tiers. Finally a 4th
tier is added to search the Logstash data with Elasticsearch and visualize it using Kibana.
Note: This use case also shows the
convenience of using a single YAML macro (declared in the dsl_definitions section
of the TOSCA Service Template) on multiple Compute nodes.
|
|
Container-1:
Containers using Docker single Compute instance (Containers only)
|
Minimalist TOSCA Service Template description of 2 Docker
containers linked to each other. Specifically, one container runs wordpress
and connects to second mysql database container both on a single
server (i.e., Compute instance). The use case also demonstrates how TOSCA
declares and references Docker images from the Docker Hub repository.
Variation 1: Docker Container nodes (only) providing their Docker
Requirements allowing platform (orchestrator) to select/provide the
underlying Docker implementation (Capability).
|
11.1.2 Compute:
Create a single Compute instance with a host Operating System
This use case demonstrates how the TOSCA Simple Profile
specification can be used to stand up a single Compute instance with a guest
Operating System using a normative TOSCA Compute
node. The TOSCA Compute node is declarative in that the service template
describes both the processor and host operating system platform characteristics
(i.e., properties declared on the capability named “os” sometimes called a “flavor”) that are
desired by the template author. The cloud provider would attempt to fulfill
these properties (to the best of its abilities) during orchestration.
11.1.2.2 Features
This use case introduces the following TOSCA Simple Profile
features:
·
A node template that uses the normative TOSCA Compute Node Type along with showing an
exemplary set of its properties being configured.
·
Use of the TOSCA Service Template inputs section to declare a configurable
value the template user may supply at runtime. In this case, the “host” property named “num_cpus” (of type integer) is declared.
o
Use of a property constraint to limit the allowed integer values
for the “num_cpus” property to a
specific list supplied in the property declaration.
·
Use of the TOSCA Service Template outputs section to declare a value the
template user may request at runtime. In this case, the property named “instance_ip” is declared
o
The “instance_ip” output
property is programmatically retrieved from the Compute node’s “public_address” attribute using the TOSCA
Service Template-level get_attribute
function.
|
tosca_definitions_version: tosca_simple_yaml_1_0
description: >
TOSCA simple profile that just
defines a single compute instance and selects a (guest) host Operating System
from the Compute node’s properties. Note, this example does not include
default values on inputs properties.
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
node_templates:
my_server:
type: Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input: cpus }
mem_size: 1 GB
os:
properties:
architecture: x86_64
type: Linux
distribution: ubuntu
version: 12.04
outputs:
private_ip:
description: The private IP
address of the deployed server instance.
value: { get_attribute:
[my_server, private_address] }
|
·
This use case uses a versioned, Linux Ubuntu distribution on the
Compute node.
11.1.3.1 Description
This use case demonstrates how the TOSCA SoftwareComponent
node type can be used to declare software that is packaged in a standard
Virtual Machine (VM) image file format (i.e., in this case QCOW2) and is hosted
on a TOSCA Compute node (instance). In this variation, the SoftwareComponent
declares a VM image as a deployment artifact that includes its own pre-packaged
operating system and software. The TOSCA Orchestrator detects this known
deployment artifact type on the SoftwareComponent node template and
automatically deploys it to the Compute node.
11.1.3.2 Features
This use case introduces the following TOSCA Simple Profile
features:
·
A node template that uses the normative TOSCA SoftwareComponent Node Type along with
showing an exemplary set of its properties being configured.
·
Use of the TOSCA Service Template artifacts section to declare a Virtual
Machine (VM) image artifact type which is referenced by the SoftwareComponent node template.
·
The VM file format, in this case QCOW2, includes its own guest
Operating System (OS) and therefore does not “require” a TOSCA OperatingSystem capability from the TOSCA
Compute node.
11.1.3.3 Assumptions
This use case assumes the following:
·
That the TOSCA Orchestrator (working with the Cloud provider’s
underlying management services) is able to instantiate a Compute node that has
a hypervisor that supports the Virtual Machine (VM) image format, in this case
QCOW2, which should be compatible with many standard hypervisors such as XEN
and KVM.
·
This is not a “bare metal” use case and assumes the existence of
a hypervisor on the machine that is allocated to “host” the Compute instance
supports (e.g. has drivers, etc.) the VM image format in this example.
11.1.3.4 Logical Diagram
11.1.3.5 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA Simple Profile with a
SoftwareComponent node with a declared Virtual machine (VM) deployment
artifact that automatically deploys to its host Compute node.
topology_template:
node_templates:
my_virtual_machine:
type: SoftwareComponent
artifacts:
my_vm_image:
file:
images/fedora-18-x86_64.qcow2
type:
tosca.artifacts.Deployment.Image.VM.QCOW2
requirements:
- host: my_server
# Automatically deploy the
VM image referenced on the create operation
interfaces:
Standard:
create: my_vm_image
# Compute instance with no
Operating System guest host
my_server:
type: Compute
capabilities:
# Note: no guest OperatingSystem requirements as these are in the image.
host:
properties:
disk_size: 10 GB
num_cpus: { get_input: cpus }
mem_size: 4 GB
outputs:
private_ip:
description: The private IP
address of the deployed server instance.
value: { get_attribute:
[my_server, private_address] }
|
11.1.3.6 Notes
·
The use of the type
keyname on the artifact definition
(within the my_virtual_machine node
template) to declare the ISO image deployment artifact type (i.e., tosca.artifacts.Deployment.Image.VM.ISO) is
redundant since the file extension is “.iso” which associated with this known,
declared artifact type.
·
This use case references a filename on the my_vm_image artifact, which indicates a
Linux, Fedora 18, x86 VM image, only as one possible example.
11.1.4 Block Storage
1: Using the normative AttachesTo Relationship Type
This use case demonstrates how to attach a TOSCA BlockStorage
node to a Compute
node using the normative AttachesTo relationship.
11.1.4.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with server
and attached block storage using the normative AttachesTo Relationship Type.
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
storage_size:
type: scalar-unit.size
description: Size of the
storage to be created.
default: 1 GB
storage_snapshot_id:
type: string
description: >
Optional identifier for an
existing snapshot to use when creating storage.
storage_location:
type: string
description: Block storage
mount point (filesystem path).
node_templates:
my_server:
type: Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 1 GB
os:
properties:
architecture: x86_64
type: linux
distribution: fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
relationship:
type: AttachesTo
properties:
location: {
get_input: storage_location }
my_storage:
type: BlockStorage
properties:
size: { get_input:
storage_size }
snapshot_id: { get_input:
storage_snapshot_id }
outputs:
private_ip:
description: The private IP
address of the newly created compute instance.
value: { get_attribute:
[my_server, private_address] }
volume_id:
description: The volume id
of the block storage instance.
value: { get_attribute:
[my_storage, volume_id] }
|
11.1.5 Block Storage 2: Using a custom
AttachesTo Relationship Type
11.1.5.1 Description
This use case demonstrates how to attach a TOSCA BlockStorage
node to a Compute
node using a custom RelationshipType that derives from the normative AttachesTo
relationship.
11.1.5.2 Logical Diagram
11.1.5.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with server
and attached block storage using a custom AttachesTo Relationship Type.
relationship_types:
MyCustomAttachesTo:
derived_from: AttachesTo
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
storage_size:
type: scalar-unit.size
description: Size of the
storage to be created.
default: 1 GB
storage_snapshot_id:
type: string
description: >
Optional identifier for an
existing snapshot to use when creating storage.
storage_location:
type: string
description: Block storage
mount point (filesystem path).
node_templates:
my_server:
type: Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4 GB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
# Declare custom
AttachesTo type using the ‘relationship’ keyword
relationship:
type: MyCustomAttachesTo
properties:
location: {
get_input: storage_location }
my_storage:
type: BlockStorage
properties:
size: { get_input:
storage_size }
snapshot_id: { get_input:
storage_snapshot_id }
outputs:
private_ip:
description: The private IP
address of the newly created compute instance.
value: { get_attribute:
[my_server, private_address] }
volume_id:
description: The volume id
of the block storage instance.
value: { get_attribute:
[my_storage, volume_id] }
|
11.1.6 Block Storage 3: Using a Relationship
Template of type AttachesTo
11.1.6.1 Description
This use case demonstrates how to attach a TOSCA BlockStorage
node to a Compute
node using a TOSCA Relationship Template that is based upon the normative AttachesTo
Relationship Type.
11.1.6.2 Logical Diagram
11.1.6.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with server
and attached block storage using a named Relationship Template for the
storage attachment.
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
storage_size:
type: scalar-unit.size
description: Size of the
storage to be created.
default: 1 GB
storage_location:
type: string
description: Block storage
mount point (filesystem path).
node_templates:
my_server:
type: Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4 GB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
# Declare template to
use with ‘relationship’ keyword
relationship:
storage_attachment
my_storage:
type: BlockStorage
properties:
size: { get_input:
storage_size }
relationship_templates:
storage_attachment:
type: AttachesTo
properties:
location: { get_input:
storage_location }
outputs:
private_ip:
description: The private IP
address of the newly created compute instance.
value: { get_attribute:
[my_server, private_address] }
volume_id:
description: The volume id
of the block storage instance.
value: { get_attribute:
[my_storage, volume_id] }
|
11.1.7 Block Storage
4: Single Block Storage shared by 2-Tier Application with custom AttachesTo
Type and implied relationships
11.1.7.1 Description
This use case shows 2 compute instances (2 tiers) with one
BlockStorage node, and also uses a custom AttachesTo Relationship that provides a
default mount point (i.e., location) which the 1st tier
uses, but the 2nd tier provides a different mount point.
Please note that this use case assumes both Compute nodes
are accessing different directories within the shared, block storage node to avoid
collisions.
11.1.7.2 Logical Diagram
11.1.7.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with a Single
Block Storage node shared by 2-Tier Application with custom AttachesTo Type
and implied relationships.
relationship_types:
MyAttachesTo:
derived_from:
tosca.relationships.AttachesTo
properties:
location:
type: string
default: /default_location
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
storage_size:
type: scalar-unit.size
default: 1 GB
description: Size of the
storage to be created.
storage_snapshot_id:
type: string
description: >
Optional identifier for an
existing snapshot to use when creating storage.
node_templates:
my_web_app_tier_1:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
relationship:
MyAttachesTo
my_web_app_tier_2:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
relationship:
type: MyAttachesTo
properties:
location:
/some_other_data_location
my_storage:
type:
tosca.nodes.BlockStorage
properties:
size: { get_input:
storage_size }
snapshot_id: { get_input:
storage_snapshot_id }
outputs:
private_ip_1:
description: The private IP
address of the application’s first tier.
value: { get_attribute:
[my_web_app_tier_1, private_address] }
private_ip_2:
description: The private IP
address of the application’s second tier.
value: { get_attribute:
[my_web_app_tier_2, private_address] }
volume_id:
description: The volume id
of the block storage instance.
value: { get_attribute:
[my_storage, volume_id] }
|
11.1.8 Block Storage 5: Single Block Storage
shared by 2-Tier Application with custom AttachesTo Type and explicit
Relationship Templates
11.1.8.1 Description
This use case is like the Notation1 use case, but also
creates two relationship templates (one for each tier) each of which provide a
different mount point (i.e., location) which overrides the default
location defined in the custom Relationship Type.
Please note that this use case assumes both Compute nodes
are accessing different directories within the shared, block storage node to
avoid collisions.
11.1.8.2 Logical Diagram
11.1.8.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with a single
Block Storage node shared by 2-Tier Application with custom AttachesTo Type
and explicit Relationship Templates.
relationship_types:
MyAttachesTo:
derived_from:
tosca.relationships.AttachesTo
properties:
location:
type: string
default: /default_location
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
storage_size:
type: scalar-unit.size
default: 1 GB
description: Size of the
storage to be created.
storage_snapshot_id:
type: string
description: >
Optional identifier for an
existing snapshot to use when creating storage.
storage_location:
type: string
description: >
Block storage mount point
(filesystem path).
node_templates:
my_web_app_tier_1:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
relationship:
storage_attachesto_1
my_web_app_tier_2:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
relationship:
storage_attachesto_2
my_storage:
type:
tosca.nodes.BlockStorage
properties:
size: { get_input:
storage_size }
snapshot_id: { get_input:
storage_snapshot_id }
relationship_templates:
storage_attachesto_1:
type: MyAttachesTo
properties:
location:
/my_data_location
storage_attachesto_2:
type: MyAttachesTo
properties:
location:
/some_other_data_location
outputs:
private_ip_1:
description: The private IP
address of the application’s first tier.
value: { get_attribute:
[my_web_app_tier_1, private_address] }
private_ip_2:
description: The private IP
address of the application’s second tier.
value: { get_attribute:
[my_web_app_tier_2, private_address] }
volume_id:
description: The volume id
of the block storage instance.
value: { get_attribute:
[my_storage, volume_id] }
|
11.1.9.1 Description
This use case demonstrates how two different TOSCA BlockStorage
nodes can be attached to two different Compute nodes (i.e., servers) each using
the normative AttachesTo
relationship.
11.1.9.2 Logical Diagram
11.1.9.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with 2 servers
each with different attached block storage.
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
storage_size:
type: scalar-unit.size
default: 1 GB
description: Size of the
storage to be created.
storage_snapshot_id:
type: string
description: >
Optional identifier for an
existing snapshot to use when creating storage.
storage_location:
type: string
description: >
Block storage mount point
(filesystem path).
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage
relationship:
type: AttachesTo
properties:
location: {
get_input: storage_location }
my_storage:
type:
tosca.nodes.BlockStorage
properties:
size: { get_input:
storage_size }
snapshot_id: { get_input:
storage_snapshot_id }
my_server2:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: Fedora
version: 18.0
requirements:
- local_storage:
node: my_storage2
relationship:
type: AttachesTo
properties:
location: {
get_input: storage_location }
my_storage2:
type:
tosca.nodes.BlockStorage
properties:
size: { get_input:
storage_size }
snapshot_id: { get_input:
storage_snapshot_id }
outputs:
server_ip_1:
description: The private IP
address of the application’s first server.
value: { get_attribute: [my_server,
private_address] }
server_ip_2:
description: The private IP
address of the application’s second server.
value: { get_attribute:
[my_server2, private_address] }
volume_id_1:
description: The volume id
of the first block storage instance.
value: { get_attribute:
[my_storage, volume_id] }
volume_id_2:
description: The volume id
of the second block storage instance.
value: { get_attribute:
[my_storage2, volume_id] }
|
11.1.10.1 Description
11.1.10.2 Logical Diagram
11.1.10.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
Tosca template for creating an
object storage service.
topology_template:
inputs:
objectstore_name:
type: string
node_templates:
obj_store_server:
type:
tosca.nodes.ObjectStorage
properties:
name: { get_input:
objectstore_name }
size: 4096 MB
maxsize: 20 GB
|
11.1.11.1 Description
Introduces the TOSCA Network and
Port nodes used for
modeling logical networks using the LinksTo and
BindsTo Relationship Types. In this use case, the
template is invoked without an existing network_name as an input property so a
new network is created using the properties declared in the Network node.
11.1.11.2 Logical Diagram
11.1.11.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with 1
server bound to a new network
topology_template:
inputs:
network_name:
type: string
description: Network name
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: 1
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: CirrOS
version: 0.3.2
my_network:
type:
tosca.nodes.network.Network
properties:
network_name: { get_input:
network_name }
ip_version: 4
cidr: '192.168.0.0/24'
start_ip: '192.168.0.50'
end_ip: '192.168.0.200'
gateway_ip: '192.168.0.1'
my_port:
type:
tosca.nodes.network.Port
requirements:
- binding: my_server
- link: my_network
|
11.1.12.1 Description
This use case shows how to use a network_name as an input parameter to the template to allow
a server to be associated with an existing network.
11.1.12.2 Logical Diagram
11.1.12.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with 1
server bound to an existing network
topology_template:
inputs:
network_name:
type: string
description: Network name
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: 1
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: CirrOS
version: 0.3.2
my_network:
type:
tosca.nodes.network.Network
properties:
network_name: { get_input:
network_name }
my_port:
type:
tosca.nodes.network.Port
requirements:
- binding:
node: my_server
- link:
node: my_network
|
11.1.13.1 Description
This use case shows how two servers (Compute nodes) can be bound to the same Network (node) using two logical network Ports.
11.1.13.2 Logical Diagram
11.1.13.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with 2
servers bound to the 1 network
topology_template:
inputs:
network_name:
type: string
description: Network name
network_cidr:
type: string
default: 10.0.0.0/24
description: CIDR for the
network
network_start_ip:
type: string
default: 10.0.0.100
description: Start IP for
the allocation pool
network_end_ip:
type: string
default: 10.0.0.150
description: End IP for the
allocation pool
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: 1
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: CirrOS
version: 0.3.2
my_server2:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: 1
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: CirrOS
version: 0.3.2
my_network:
type:
tosca.nodes.network.Network
properties:
ip_version: 4
cidr: { get_input:
network_cidr }
network_name: { get_input:
network_name }
start_ip: { get_input:
network_start_ip }
end_ip: { get_input:
network_end_ip }
my_port:
type: tosca.nodes.network.Port
requirements:
- binding: my_server
- link: my_network
my_port2:
type:
tosca.nodes.network.Port
requirements:
- binding: my_server2
- link: my_network
|
11.1.14.1 Description
This use case shows how three logical networks (Network),
each with its own IP address range, can be bound to with the same server
(Compute node).
11.1.14.2 Logical Diagram
11.1.14.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with 1
server bound to 3 networks
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: 1
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: Linux
distribution: CirrOS
version: 0.3.2
my_network1:
type:
tosca.nodes.network.Network
properties:
cidr: '192.168.1.0/24'
network_name: net1
my_network2:
type:
tosca.nodes.network.Network
properties:
cidr: '192.168.2.0/24'
network_name: net2
my_network3:
type:
tosca.nodes.network.Network
properties:
cidr: '192.168.3.0/24'
network_name: net3
my_port1:
type:
tosca.nodes.network.Port
properties:
order: 0
requirements:
- binding: my_server
- link: my_network1
my_port2:
type:
tosca.nodes.network.Port
properties:
order: 1
requirements:
- binding: my_server
- link: my_network2
my_port3:
type:
tosca.nodes.network.Port
properties:
order: 2
requirements:
- binding: my_server
- link: my_network3
|
11.1.15.1 Description
TOSCA simple profile service showing the WordPress web
application with a MySQL database hosted on a single server (instance).
11.1.15.2 Logical Diagram
11.1.15.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with
WordPress, a web server, a MySQL DBMS hosting the application’s database
content on the same server. Does not have input defaults or constraints.
topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs
for the server.
db_name:
type: string
description: The name of the
database.
db_user:
type: string
description: The username of
the DB user.
db_pwd:
type: string
description: The WordPress
database admin account password.
db_root_pwd:
type: string
description: Root password
for MySQL.
db_port:
type: PortDef
description: Port for the
MySQL database
node_templates:
wordpress:
type:
tosca.nodes.WebApplication.WordPress
properties:
context_root: { get_input:
context_root }
requirements:
- host: webserver
- database_endpoint:
mysql_database
interfaces:
Standard:
create: wordpress_install.sh
configure:
implementation: wordpress_configure.sh
inputs:
wp_db_name: {
get_property: [ mysql_database, name ] }
wp_db_user: {
get_property: [ mysql_database, user ] }
wp_db_password: {
get_property: [ mysql_database, password ] }
# In my own
template, find requirement/capability, find port property
wp_db_port: {
get_property: [ SELF, database_endpoint, port ] }
mysql_database:
type: Database
properties:
name: { get_input: db_name
}
user: { get_input: db_user
}
password: { get_input:
db_pwd }
port: { get_input: db_port
}
capabilities:
database_endpoint:
properties:
port: { get_input:
db_port }
requirements:
- host: mysql_dbms
interfaces:
Standard:
configure: mysql_database_configure.sh
mysql_dbms:
type: DBMS
properties:
root_password: {
get_input: db_root_pwd }
port: { get_input: db_port
}
requirements:
- host: server
interfaces:
Standard:
inputs:
db_root_password: {
get_property: [ mysql_dbms, root_password ] }
create: mysql_dbms_install.sh
start: mysql_dbms_start.sh
configure: mysql_dbms_configure.sh
webserver:
type: WebServer
requirements:
- host: server
interfaces:
Standard:
create: webserver_install.sh
start: webserver_start.sh
server:
type: Compute
capabilities:
host:
properties:
disk_size: 10 GB
num_cpus: { get_input:
cpus }
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: linux
distribution: fedora
version: 17.0
outputs:
website_url:
description: URL for
Wordpress wiki.
value: { get_attribute:
[server, public_address] }
|
11.1.15.4 Sample scripts
Where the referenced implementation scripts in the
example above would have the following contents
11.1.15.4.1 wordpress_install.sh
11.1.15.4.2 wordpress_configure.sh
|
sed -i "/Deny from
All/d" /etc/httpd/conf.d/wordpress.conf
sed -i "s/Require
local/Require all granted/" /etc/httpd/conf.d/wordpress.conf
sed -i s/database_name_here/name/
/etc/wordpress/wp-config.php
sed -i s/username_here/user/
/etc/wordpress/wp-config.php
sed -i s/password_here/password/
/etc/wordpress/wp-config.php
systemctl restart httpd.service
|
11.1.15.4.3 mysql_database_configure.sh
|
# Setup MySQL root password and
create user
cat << EOF | mysql -u root
--password=db_root_password
CREATE DATABASE name;
GRANT ALL PRIVILEGES ON name.* TO
"user"@"localhost"
IDENTIFIED BY
"password";
FLUSH PRIVILEGES;
EXIT
EOF
|
11.1.15.4.4 mysql_dbms_install.sh
|
yum -y install mysql mysql-server
# Use systemd to start MySQL
server at system boot time
systemctl enable mysqld.service
|
11.1.15.4.5 mysql_dbms_start.sh
|
# Start the MySQL service (NOTE:
may already be started at image boot time)
systemctl start mysqld.service
|
11.1.15.4.6 mysql_dbms_configure
|
# Set the MySQL server root
password
mysqladmin -u root password
db_root_password
|
11.1.15.4.7 webserver_install.sh
|
yum -y install httpd
systemctl enable httpd.service
|
11.1.15.4.8 webserver_start.sh
|
# Start the httpd service (NOTE:
may already be started at image boot time)
systemctl start httpd.service
|
11.1.16.1 Description
This use case Instantiates a 2-tier application with Nodejs
and its (PayPal sample) WebApplication on one tier which connects a MongoDB
database (which stores its application data) using a ConnectsTo relationship.
11.1.16.2 Logical Diagram
11.1.16.3 Sample YAML
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with a
nodejs web server hosting a PayPal sample application which connects to a
mongodb database.
imports:
- custom_types/paypalpizzastore_nodejs_app.yaml
dsl_definitions:
ubuntu_node: &ubuntu_node
disk_size: 10 GB
num_cpus: { get_input:
my_cpus }
mem_size: 4096 MB
os_capabilities:
&os_capabilities
architecture: x86_64
type: Linux
distribution: Ubuntu
version: 14.04
topology_template:
inputs:
my_cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
default: 1
github_url:
type: string
description: The URL to
download nodejs.
default:
https://github.com/sample.git
node_templates:
paypal_pizzastore:
type:
tosca.nodes.WebApplication.PayPalPizzaStore
properties:
github_url: { get_input:
github_url }
requirements:
- host:nodejs
- database_connection:
mongo_db
interfaces:
Standard:
configure:
implementation:
scripts/nodejs/configure.sh
inputs:
github_url: {
get_property: [ SELF, github_url ] }
mongodb_ip: {
get_attribute: [mongo_server, private_address] }
start:
scriptsscripts/nodejs/start.sh
nodejs:
type:
tosca.nodes.WebServer.Nodejs
requirements:
- host: app_server
interfaces:
Standard:
create:
scripts/nodejs/create.sh
mongo_db:
type: tosca.nodes.Database
requirements:
- host: mongo_dbms
interfaces:
Standard:
create:
create_database.sh
mongo_dbms:
type: tosca.nodes.DBMS
requirements:
- host: mongo_server
properties:
port: 27017
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
mongodb/create.sh
configure:
implementation:
mongodb/config.sh
inputs:
mongodb_ip: {
get_attribute: [mongo_server, private_address] }
start: mongodb/start.sh
mongo_server:
type: tosca.nodes.Compute
capabilities:
os:
properties:
*os_capabilities
host:
properties: *ubuntu_node
app_server:
type: tosca.nodes.Compute
capabilities:
os:
properties:
*os_capabilities
host:
properties: *ubuntu_node
outputs:
nodejs_url:
description: URL for the
nodejs server, http://<IP>:3000
value: { get_attribute:
[app_server, private_address] }
mongodb_url:
description: URL for the
mongodb server.
value: { get_attribute: [
mongo_server, private_address ] }
|
·
Scripts referenced in this example are assumed to be placed by
the TOSCA orchestrator in the relative directory declared in TOSCA.meta of the
TOSCA CSAR file.
11.1.17.1 Description
TOSCA simple profile service showing the Nodejs, MongoDB,
Elasticsearch, Logstash, Kibana, rsyslog and collectd installed on a different
server (instance).
This use case also demonstrates:
·
Use of TOSCA macros or dsl_definitions
·
Multiple SoftwareComponents
hosted on same Compute node
·
Multiple tiers communicating to each other over ConnectsTo using
Configure interface.
11.1.17.2 Logical Diagram
11.1.17.3 Sample YAML
11.1.17.3.1 Master Service Template application (Entry-Definitions)
TheThe following YAML is the primary template (i.e., the
Entry-Definition) for the overall use case. The imported YAML for the various
subcomponents are not shown here for brevity.
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
This TOSCA simple profile
deploys nodejs, mongodb, elasticsearch, logstash and kibana each on a
separate server with monitoring enabled for nodejs server where a sample
nodejs application is running. The syslog and collectd are installed on a
nodejs server.
imports:
-
paypalpizzastore_nodejs_app.yaml
- elasticsearch.yaml
- logstash.yaml
- kibana.yaml
- collectd.yaml
- rsyslog.yaml
dsl_definitions:
host_capabilities:
&host_capabilities
# container properties
(flavor)
disk_size: 10 GB
num_cpus: { get_input:
my_cpus }
mem_size: 4096 MB
os_capabilities:
&os_capabilities
architecture: x86_64
type: Linux
distribution: Ubuntu
version: 14.04
topology_template:
inputs:
my_cpus:
type: integer
description: Number of CPUs
for the server.
constraints:
- valid_values: [ 1, 2, 4,
8 ]
github_url:
type: string
description: The URL to
download nodejs.
default:
https://github.com/sample.git
node_templates:
paypal_pizzastore:
type:
tosca.nodes.WebApplication.PayPalPizzaStore
properties:
github_url: { get_input:
github_url }
requirements:
- host: nodejs
- database_connection:
mongo_db
interfaces:
Standard:
configure:
implementation:
scripts/nodejs/configure.sh
inputs:
github_url: {
get_property: [ SELF, github_url ] }
mongodb_ip: {
get_attribute: [mongo_server, private_address] }
start:
scripts/nodejs/start.sh
nodejs:
type:
tosca.nodes.WebServer.Nodejs
requirements:
- host: app_server
interfaces:
Standard:
create:
scripts/nodejs/create.sh
mongo_db:
type: tosca.nodes.Database
requirements:
- host: mongo_dbms
interfaces:
Standard:
create:
create_database.sh
mongo_dbms:
type: tosca.nodes.DBMS
requirements:
- host: mongo_server
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
scripts/mongodb/create.sh
configure:
implementation:
scripts/mongodb/config.sh
inputs:
mongodb_ip: {
get_attribute: [mongo_server, ip_address] }
start:
scripts/mongodb/start.sh
elasticsearch:
type:
tosca.nodes.SoftwareComponent.Elasticsearch
requirements:
- host:
elasticsearch_server
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
scripts/elasticsearch/create.sh
start:
scripts/elasticsearch/start.sh
logstash:
type:
tosca.nodes.SoftwareComponent.Logstash
requirements:
- host: logstash_server
- search_endpoint:
elasticsearch
interfaces:
tosca.interfaces.relationship.Configure:
pre_configure_source:
implementation:
python/logstash/configure_elasticsearch.py
input:
elasticsearch_ip: { get_attribute: [elasticsearch_server, ip_address] }
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
scripts/lostash/create.sh
configure:
scripts/logstash/config.sh
start:
scripts/logstash/start.sh
kibana:
type:
tosca.nodes.SoftwareComponent.Kibana
requirements:
- host: kibana_server
- search_endpoint:
elasticsearch
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
scripts/kibana/create.sh
configure:
implementation:
scripts/kibana/config.sh
input:
elasticsearch_ip: {
get_attribute: [elasticsearch_server, ip_address] }
kibana_ip: {
get_attribute: [kibana_server, ip_address] }
start:
scripts/kibana/start.sh
app_collectd:
type:
tosca.nodes.SoftwareComponent.Collectd
requirements:
- host: app_server
- collectd_endpoint:
logstash
interfaces:
tosca.interfaces.relationship.Configure:
pre_configure_target:
implementation:
python/logstash/configure_collectd.py
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
scripts/collectd/create.sh
configure:
implementation:
python/collectd/config.py
input:
logstash_ip: {
get_attribute: [logstash_server, ip_address] }
start: scripts/collectd/start.sh
app_rsyslog:
type:
tosca.nodes.SoftwareComponent.Rsyslog
requirements:
- host: app_server
- rsyslog_endpoint:
logstash
interfaces:
tosca.interfaces.relationship.Configure:
pre_configure_target:
implementation:
python/logstash/configure_rsyslog.py
interfaces:
tosca.interfaces.node.lifecycle.Standard:
create:
scripts/rsyslog/create.sh
configure:
implementation:
scripts/rsyslog/config.sh
input:
logstash_ip: {
get_attribute: [logstash_server, ip_address] }
start:
scripts/rsyslog/start.sh
app_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
*host_capabilities
os:
properties:
*os_capabilities
mongo_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
*host_capabilities
os:
properties:
*os_capabilities
elasticsearch_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
*host_capabilities
os:
properties:
*os_capabilities
logstash_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
*host_capabilities
os:
properties:
*os_capabilities
kibana_server:
type: tosca.nodes.Compute
capabilities:
host:
properties: *host_capabilities
os:
properties:
*os_capabilities
outputs:
nodejs_url:
description: URL for the
nodejs server.
value: { get_attribute: [
app_server, private_address ] }
mongodb_url:
description: URL for the
mongodb server.
value: { get_attribute: [
mongo_server, private_address ] }
elasticsearch_url:
description: URL for the
elasticsearch server.
value: { get_attribute: [
elasticsearch_server, private_address ] }
logstash_url:
description: URL for the
logstash server.
value: { get_attribute: [
logstash_server, private_address ] }
kibana_url:
description: URL for the
kibana server.
value: { get_attribute: [ kibana_server, private_address ] }
|
11.1.17.4 Sample scripts
Where the referenced implementation scripts in the
example above would have the following contents
11.1.18 Container-1:
Containers using Docker single Compute instance (Containers only)
11.1.18.1 Description
This use case shows a minimal description of two Container
nodes (only) providing their Docker Requirements allowing platform
(orchestrator) to select/provide the underlying Docker implementation
(Capability). Specifically, wordpress and mysql Docker images are referenced
from Docker Hub.
This use case also demonstrates:
·
Abstract description of Requirements (i.e., Container and Docker)
allowing platform to dynamically select the appropriate runtime Capabilities
that match.
·
Use of external repository (Docker Hub) to reference image artifact.
11.1.18.2 Logical Diagram
11.1.18.3 Sample YAML
11.1.18.3.1 Two Docker “Container” nodes (Only) with Docker Requirements
|
tosca_definitions_version:
tosca_simple_yaml_1_0
description: >
TOSCA simple profile with
wordpress, web server and mysql on the same server.
# Repositories to retrieve code
artifacts from
repositories:
docker_hub:
https://registry.hub.docker.com/
topology_template:
inputs:
wp_host_port:
type: integer
description: The host port
that maps to port 80 of the WordPress container.
db_root_pwd:
type: string
description: Root password
for MySQL.
node_templates:
# The MYSQL container based on
official MySQL image in Docker hub
mysql_container:
type:
tosca.nodes.Container.Application.Docker
capabilities:
# This is a capability
that would mimic the Docker –link feature
database_link:
tosca.capabilities.Docker.Link
artifacts:
my_image:
file: mysql
type:
tosca.artifacts.Deployment.Image.Container.Docker
repository: docker_hub
interfaces:
Standard:
create:
implementation:
my_image
inputs:
db_root_password: {
get_input: db_root_pwd }
# The WordPress container
based on official WordPress image in Docker hub
wordpress_container:
type:
tosca.nodes.Container.Application.Docker
requirements:
- database_link:
mysql_container
artifacts:
my_image:
file: wordpress
type:
tosca.artifacts.Deployment.Image.Container.Docker
repository: docker_hub
interfaces:
Standard:
create:
implementation:
my_image
inputs:
host_port: {
get_input: wp_host_port }
|
This section is non-normative and describes the
approach TOSCA Simple Profile plans to take for policy description with TOSCA
Service Templates. In addition, it explores how existing TOSCA Policy Types
and definitions might be applied in the future to express operational policy
use cases.
TOSCA Policies are a type of requirement that govern use or
access to resources which can be expressed independently from specific
applications (or their resources) and whose fulfillment is not discretely
expressed in the application’s topology (i.e., via TOSCA Capabilities).
TOSCA deems it not desirable for a declarative model to
encourage external intervention for resolving policy issues (i.e., via
imperative mechanisms external to the Cloud). Instead, the Cloud provider is
deemed to be in the best position to detect when policy conditions are
triggered, analyze the affected resources and enforce the policy against the
allowable actions declared within the policy itself.
·
Natural language rules are not realistic, too much to represent
in our specification; however, regular expressions can be used that include
simple operations and operands that include symbolic names for TOSCA metamodel
entities, properties and attributes.
·
Complex rules can actually be directed to an external policy
engine (to check for violation) returns true|false then policy says what to do
(trigger or action).
·
Actions/Triggers could be:
·
Autonomic/Platform corrects against user-supplied criteria
·
External monitoring service could be utilized to monitor policy
rules/conditions against metrics, the monitoring service could coordinate
corrective actions with external services (perhaps Workflow engines that can
analyze the application and interact with the TOSCA instance model).
Policies typically address two major areas of concern for
customer workloads:
·
Access Control – assures user and service access to
controlled resources are governed by rules which determine general access
permission (i.e., allow or deny) and conditional access dependent on other
considerations (e.g., organization role, time of day, geographic location,
etc.).
·
Placement – assures affinity (or anti-affinity) of
deployed applications and their resources; that is, what is allowed to be
placed where within a Cloud provider’s infrastructure.
·
Quality-of-Service (and continuity) - assures performance
of software components (perhaps captured as quantifiable, measure components
within an SLA) along with consideration for scaling and failover.
Although TOSCA Policy definitions could be used to express
and convey access control policies, definitions of policies in this area are
out of scope for this specification. At this time, TOSCA encourages
organizations that already have standards that express policy for access
control to provide their own guidance on how to use their standard with TOSCA.
There must be
control mechanisms in place that can be part of these patterns that accept
governance policies that allow control expressions of what is allowed when
placing, scaling and managing the applications that are enforceable and
verifiable in Cloud.
These policies need to consider the following:
·
Regulated industries need applications to control placement
(deployment) of applications to different countries or regions (i.e., different
logical geographical boundaries).
12.3.2.1 Placement for governance concerns
In general, companies and individuals have security concerns
along with general “loss of control” issues when considering deploying and
hosting their highly valued application and data to the Cloud. They want to
control placement perhaps to ensure their applications are only placed in
datacenter they trust or assure that their applications and data are not placed
on shared resources (i.e., not co-tenanted).
In addition, companies that are related to highly regulated
industries where compliance with government, industry and corporate policies is
paramount. In these cases, having the ability to control placement of
applications is an especially significant consideration and a prerequisite for
automated orchestration.
12.3.2.2 Placement for failover
Companies realize that their day-to-day business must
continue on through unforeseen disasters that might disable instances of the
applications and data at or on specific data centers, networks or servers.
They need to be able to convey placement policies for their software
applications and data that mitigate risk of disaster by assuring these cloud
assets are deployed strategically in different physical locations. Such
policies need to consider placement across geographic locations as wide as
countries, regions, datacenters, as well as granular placement on a network,
server or device within the same physical datacenter. Cloud providers must be
able to not only enforce these policies but provide robust and seamless
failover such that a disaster’s impact is never perceived by the end user.
Quality-of-Service
(apart from failover placement considerations) typically assures that software
applications and data are available and performant to the end users. This is
usually something that is measurable in terms of end-user responsiveness (or response
time) and often qualified in SLAs established between the Cloud provider and
customer. These QoS aspects can be taken from SLAs and legal agreements and
further encoded as performance policies associated with the actual applications
and data when they are deployed. It is assumed that Cloud provider is able to
detect high utilization (or usage load) on these applications and data that
deviate from these performance policies and is able to bring them back into
compliance.
·
Performance policies can be related to scalability policies.
Scalability policies tell the Cloud provider exactly how to scale
applications and data when they detect an application’s performance policy is
(or about to be) violated (or triggered).
·
Scalability policies in turn are related to placement policies
which govern where the application and data can be scaled to.
·
There are general “tenant” considerations that restrict what
resources are available to applications and data based upon the contract a
customer has with the Cloud provider. This includes other constraints imposed
by legal agreements or SLAs that are not encoded programmatically or associated
directly with actual application or data.
12.5 Use Cases
This section includes some initial operation policy use
cases that we wish to describe using the TOSCA metamodel. More policy work
will be done in future versions of the TOSCA Simple Profile in YAML
specification.
12.5.1.1 Use Case 1: Simple placement for failover
12.5.1.1.1 Description
This use case shows a failover policy to keep at least 3
copies running in separate containers. In this simple case, the specific
containers to use (or name is not important; the Cloud provider must assure
placement separation (anti-affinity) in three physically separate containers.
12.5.1.1.2 Features
This use case introduces the following policy features:
·
Simple separation on different “compute” nodes (up to discretion
of provider).
·
Simple separation by region (a logical container type) using an
allowed list of region names relative to the provider.
o
Also, shows that set of allowed “regions” (containers) can be
greater than the number of containers requested.
12.5.1.1.3 Logical Diagram
Sample YAML: Compute separation
|
failover_policy_1:
type:
tosca.policy.placement.Antilocate
description: My placement policy
for Compute node separation
properties:
# 3 diff target containers
container type: Compute
container_number: 3
|
12.5.1.1.4 Notes
·
There may be availability (constraints) considerations especially
if these policies are applied to “clusters”.
·
There may be future considerations for controlling max # of
instances per container.
12.5.1.2 Use Case 2: Controlled placement by region
12.5.1.2.1 Description
This use case demonstrates the use of named “containers”
which could represent the following:
·
Datacenter regions
·
Geographic regions (e.g., cities, municipalities, states,
countries, etc.)
·
Commercial regions (e.g., North America, Eastern Europe, Asia
Pacific, etc.)
12.5.1.2.2 Features
This use case introduces the following policy features:
·
Separation of resources (i.e., TOSCA nodes) by logical regions,
or zones.
12.5.1.2.3 Sample YAML: Region separation amongst named set of regions
|
failover_policy_2:
type: tosca.policy.placement
description: My failover policy
with allowed target regions (logical containers)
properties:
container type: region
container_number: 3
# If “containers” keyname is
provided, they represent the allowed set
# of target containers to use
for placement for .
containers: [ region1,
region2, region3, region4 ]
|
12.5.1.3 Use Case 3: Co-locate based upon Compute affinity
12.5.1.3.1 Description
Nodes that need to be co-located to achieve optimal
performance based upon access to similar Infrastructure (IaaS) resource types
(i.e., Compute, Network and/or Storage).
This use case demonstrates the co-location based upon
Compute resource affinity; however, the same approach could be taken for
Network as or Storage affinity as well. :
12.5.1.3.2 Features
This use case introduces the following policy features:
·
Node placement based upon Compute resource affinity.
12.5.1.4 Notes
·
The concept of placement based upon IaaS resource utilization is
not future-thinking, as Cloud should guarantee equivalent performance of
application performance regardless of placement. That is, all network access
between application nodes and underlying Compute or Storage should have
equivalent performance (e.g., network bandwidth, network or storage access
time, CPU speed, etc.).
12.5.1.4.1 Sample YAML: Region separation amongst named set of regions
|
keep_together_policy:
type: tosca.policy.placement.Colocate
description: Keep associated
nodes (groups of nodes) based upon Compute
properties:
affinity: Compute
|
12.5.2.1 Use Case 1: Simple node autoscale
12.5.2.1.1 Description
Start with X nodes and scale up to Y nodes, capability to do
this from a dashboard for example.
12.5.2.1.2 Features
This use case introduces the following policy features:
·
Basic autoscaling policy
12.5.2.1.3 Sample YAML
|
my_scaling_policy_1:
type: tosca.policy.scaling
description: Simple node
autoscaling
properties:
min_instances: <integer>
max_instances: <integer>
default_instances:
<integer>
increment: <integer>
|
12.5.2.1.4 Notes
·
Assume horizontal scaling for this use case
o Horizontal
scaling, implies “stack-level” control using Compute nodes to define a “stack”
(i.e., The Compute node’s entire HostedOn relationship dependency graph is
considered part of its “stack”)
·
Assume Compute node has a
SoftwareComponent that represents a VM application.
·
Availability Zones (and Regions if
not same) need to be considered in further use cases.
·
If metrics are introduced, there is a control-loop (that
monitors). Autoscaling is a special concept that includes these
considerations.
·
Mixed placement and scaling use cases need to be considered:
o Example:
Compute1 and Compute2
are 2 node templates. Compute1 has 10 instances,
5 in one region 5 in other region.
The implementations subject to conformance are those introduced
in Section 11.3 “Implementations”. They are listed here for convenience:
·
TOSCA YAML service template
·
TOSCA processor
·
TOSCA orchestrator (also called orchestration engine)
·
TOSCA generator
·
TOSCA archive
A document conforms to this specification as TOSCA YAML
service template if it satisfies all the statements below:
(a) It is valid according
to the grammar, rules and requirements defined in section 3 “TOSCA Simple
Profile definitions in YAML”.
(b) When using functions
defined in section 4 “TOSCA functions”, it is valid according to the grammar
specified for these functions.
(c) When using or
referring to data types, artifact types, capability types, interface types,
node types, relationship types, group types, policy types defined in section 5
“TOSCA normative type definitions”, it is valid according to the definitions
given in section 5.
A processor or program conforms to this specification as
TOSCA processor if it satisfies all the statements below:
(a) It can parse and recognize
the elements of any conforming TOSCA YAML service template, and generates
errors for those documents that fail to conform as TOSCA YAML service template
while clearly intending to.
(b) It implements the
requirements and semantics associated with the definitions and grammar in
section 3 “TOSCA Simple Profile definitions in YAML”, including those listed in
the “additional requirements” subsections.
(c) It resolves the
imports, either explicit or implicit, as described in section 3 “TOSCA Simple
Profile definitions in YAML”.
(d) It generates errors as
required in error cases described in sections 3.1 (TOSCA Namespace URI and
alias), 3.2 (Parameter and property type) and 3.6 (Type-specific definitions).
(e) It normalizes string
values as described in section 5.4.9.3 (Additional Requirements)
A processor or program conforms to this specification as
TOSCA orchestrator if it satisfies all the statements below:
(a) It is conforming as a
TOSCA Processor as defined in conformance clause 2: TOSCA Processor.
(b) It can process all
types of artifact described in section 5.3 “Artifact types” according to the
rules and grammars in this section.
(c) It can process TOSCA
archives as intended in section 6 “TOSCA Cloud Service Archive (CSAR) format”
and other related normative sections.
(d) It can understand and
process the functions defined in section 4 “TOSCA functions” according to their
rules and semantics.
(e) It can understand and
process the normative type definitions according to their semantics and requirements
as described in section 5 “TOSCA normative type definitions”.
(f) It can
understand and process the networking types and semantics defined in section 7
“TOSCA Networking”.
(g) It generates errors as
required in error cases described in sections 2.10 (Using node template
substitution for chaining subsystems), 5.4 (Capabilities Types) and 5.7 (Interface
Types).).
A processor or program conforms to this specification as
TOSCA generator if it satisfies at least one of the statements below:
(a) When requested to
generate a TOSCA service template, it always produces a conforming TOSCA
service template, as defined in Clause 1: TOSCA YAML service template,
(b) When requested to
generate a TOSCA archive, it always produces a conforming TOSCA archive, as
defined in Clause 5: TOSCA archive.
A package artifact conforms to this specification as TOSCA
archive if it satisfies all the statements below:
(a)
It is valid according to the structure and rules defined in section 6
“TOSCA Cloud Service Archive (CSAR) format”.
The following items will need to be reflected in the TOSCA
(XML) specification to allow for isomorphic mapping between the XML and YAML
service templates.
A.1 Model Changes
·
The “TOSCA Simple ‘Hello World’” example introduces this concept
in Section 2. Specifically, a
VM image assumed to accessible by the cloud provider.
·
Introduce template Input and Output parameters
·
The “Template with input and output parameter” example introduces
concept in Section 2.1.1.
·
“Inputs” could be mapped to BoundaryDefinitions in TOSCA v1.0.
Maybe needs some usability enhancement and better description.
·
“outputs” are a new feature.
·
Grouping of Node Templates
·
This was part of original TOSCA proposal, but removed early on
from v1.0 This allows grouping of node templates that have some type of
logically managed together as a group (perhaps to apply a scaling or placement
policy).
·
Lifecycle Operation definition independent/separate from Node
Types or Relationship types (allows reuse). For now, we added definitions for
“node.lifecycle” and “relationship.lifecycle”.
·
Override of Interfaces (operations) in the Node Template.
·
Service Template Naming/Versioning
·
Should include TOSCA spec. (or profile) version number (as part
of namespace)
·
Allow the referencing artifacts using a URL (e.g., as a property
value).
·
Repository definitions in Service Template.
·
Substitution mappings for Topology template.
·
Addition of Group Type, Policy Type, Group def., Policy def.
along with normative TOSCA base types for policies and groups.
A.2 Normative Types
·
Constraints
·
constraint clauses, regex
·
Types / Property / Parameters
·
list, map, range, scalar-unit types
·
Includes YAML intrinsic types
·
NetworkInfo, PortInfo, PortDef, PortSpec, Credential
·
TOSCA Version based on Maven
·
Node
·
Root, Compute, ObjectStorage, BlockStorage, Network, Port,
SoftwareComponent, WebServer, WebApplicaton, DBMS, Database, Container, and
others
·
Relationship
·
Root, DependsOn, HostedOn, ConnectsTo, AttachesTo, RoutesTo,
BindsTo, LinksTo and others
·
Artifact
·
Deployment: Image Types (e.g., VM, Container), ZIP, TAR, etc.
·
Implementation: File, Bash, Python, etc.
·
Requirements
·
None
·
Capabilities
·
Container, Endpoint, Attachment, Scalable, …
·
Lifecycle
·
Standard (for Node Types)
·
Configure (for Relationship Types)
·
Functions
·
get_input, get_attribute, get_property, get_nodes_of_type,
get_operation_output and others
·
concat, token
·
get_artifact
·
Groups
·
Root
·
Policies
·
Root, Placement, Scaling, Update, Performance
·
Workflow
The following individuals have participated in the creation
of this specification and are gratefully acknowledged:
Contributors:
Avi Vachnis (avi.vachnis@alcatel-lucent.com),
Alcatel-Lucent
Chris Lauwers (lauwers@ubicity.com)
Derek Palma (dpalma@vnomic.com), Vnomic
Frank Leymann (Frank.Leymann@informatik.uni-stuttgart.de),
Univ. of Stuttgart
Gerd Breiter (gbreiter@de.ibm.com), IBM
Hemal Surti (hsurti@cisco.com), Cisco
Ifat Afek (ifat.afek@alcatel-lucent.com),
Alcatel-Lucent
Idan Moyal, (idan@gigaspaces.com), Gigaspaces
Jacques Durand (jdurand@us.fujitsu.com), Fujitsu
Jin Qin, (chin.qinjin@huawei.com), Huawei
Jeremy Hess, (jeremy@gigaspaces.com) , Gigaspaces
John Crandall, (mailto:jcrandal@brocade.com), Brocade
Juergen Meynert (juergen.meynert@ts.fujitsu.com),
Fujitsu
Kapil Thangavelu (kapil.thangavelu@canonical.com),
Canonical
Karsten Beins (karsten.beins@ts.fujitsu.com),
Fujitsu
Kevin Wilson (kevin.l.wilson@hp.com), HP
Krishna Raman (kraman@redhat.com),
Red Hat
Luc Boutier (luc.boutier@fastconnect.fr), FastConnect
Luca Gioppo, (luca.gioppo@csi.it), CSI-Piemonte
Matt Rutkowski (mrutkows@us.ibm.com), IBM
Moshe Elisha (moshe.elisha@alcatel-lucent.com),
Alcatel-Lucent
Nate Finch (nate.finch@canonical.com), Canonical
Nikunj Nemani (nnemani@vmware.com),
WMware
Richard Probst (richard.probst@sap.com),
SAP AG
Sahdev Zala (spzala@us.ibm.com), IBM
Shitao li (lishitao@huawei.com), Huawei
Simeon Monov (sdmonov@us.ibm.com), IBM
Sivan Barzily, (sivan@gigaspaces.com), Gigaspaces
Sridhar Ramaswamy (sramasw@brocade.com), Brocade
Stephane Maes (stephane.maes@hp.com), HP
Thomas Spatzier (thomas.spatzier@de.ibm.com), IBM
Ton Ngo (ton@us.ibm.com), IBM
Travis Tripp (travis.tripp@hp.com), HP
Vahid Hashemian (vahidhashemian@us.ibm.com), IBM
Wayne Witzel (wayne.witzel@canonical.com),
Canonical
Yaron Parasol (yaronpa@gigaspaces.com),
Gigaspaces
|
Revision
|
Date
|
Editor
|
Changes Made
|
|
WD01, Rev01
|
2016-01-06
|
Matt Rutkowski, IBM
|
· Initial WD01,
Revision 01 baseline for TOSCA Simple Profile in YAML v1.1
· Cha. 10 Removed
URL column for use cases in favor of a single link to Git directory where
they can be found.
· Metadata added to
top-level entities
· Policy
grammar/schema fully defined.
· Ch5. Defined TOSCA
Entity Root type which is now the parent type for all TOSCA top-level types
(i.e., Artifact, Capability, Relationship, Node, Group, Policy, etc.).
Updated all top-level definitions to reflect in “derived_from” keyname.
· Added TimeInterval
Data Type
· 3.5.16.1: Added
keyname “schedule”.
|
|
WD01, Rev02
|
2016-01-25
|
Matt Rutkowski, IBM
|
· 5: Removed
tosca.Root type from chapter 5 until ad-hoc can agree on use cases likely to
come from the TOSCA instance model WG.
· Cleaned up TOSCA
Entity Root Reorganization.
|
|
WD01, Rev03
|
2016-03-22
|
Matt Rutkowski, IBM
|
· 3.5.7, 3.9.3: Fixed
“import” grammar (section 3.5.7) and reference to it in repository example
(section 3.9.3.9.3)
· 3.6.11.2 – Group
Type – clarified group types could have members that were other groups types.
· 5.2.5: Fixed
NetworkInfo (section 5.2.5) example which was missing the ‘properties’
keyword.
· 5.2.6: Clarified
PortDef examples (section 5.2.6)
· 5.2.7: Fixed
PortSpec (section 5.2.7) definition to assure that target, target_range,
source and source_range properties were not ‘required’ in schema.
·
· Fixed the following
issues raised by TC Admin.:
·
Margins should be 1" top, 1" right and left,
0.5" bottom. [this will center the "new" footer, which is
currently offset].
·
The footer uses different font size (Arial 10 instead of Arial
8) and wording ("Standards Track Draft" instead of "Standards
Track Work Product").
·
Set the following three styles to use Arial 10:
·
"Normal around table"
·
"List Paragraph"
·
"List Bullet 3"
·
Around section 2.10.1, we corrected some text in the wrong font
by re-applying the "normal" style.
·
In Section 1.8 Glossary that "Node Template" definition
starts off with "Relationship Template" Is that correct? Also, the
paragraph formatting of the definitions seems to use weird indenting.
·
In section 5.7.4.4, the diagram overlays the footer. We fixed
this on our side by setting the preceding paragraph attribute to "keep
with next".
·
In section 2.10.2, second paragraph after Figure 1, there is a
reference to "Section 0". The link jumps to 2.9.2. Is this
correct?
·
The table of examples is labelled Table of Figures. Also, the
paragraph styles of these two titles should be changed from "Body
text" to "Level 1", so they will show up in the TOC.
3.6.5 Interface Type –
missing “derived_from” in keyname table, grammar and example.
|
|
WD01, Rev04
|
2016-03-23
|
Matt Rutkowski, IBM
|
· 5.2: Added section
discussing TOSCA normative type names, their treatment and requirements to
respect case (i.e., be case sensitive) when processing.
· 3.6: All data types
that are entity types now have their keyname tables reference the common
keynames listed in section 3.6.1 TOSCA Entity schema.
· 3.6.11: Added
attributes, requirements and capabilities keynames to Group Type making it
more like a Node Type (no artifacts, still logical aggregator of a set of
nodes).
· 5.9.11: Added the
“network” (i.e, Endpoint) and “storage” (i.e., Storage) capabilities to the
Container.Application node type.
|
|
WD01, Rev05
|
2016-04-20
|
Matt Rutkowski, IBM
|
· 3.1: Bumped version
number to 1.1
· 5.3.2: typo.
‘userh’ -> ‘user’ in keyname table
· 3.6.4.4 Artifact
Type - Added a note regarding “mime types” to reference official list of
Apache mime types to give reader a sutiable reference for expected values.
·
|
|
WDO1, Rev06
|
2016-17-05
|
Luc Boutier, FastConnect
|
· 3.5.14.2.2 replaced
Node Type by Node Template.
· 3.5.17: Add
workflow activity definition
· 3.5.18: Add
workflow precondition definition
· 3.5.19: Add
workflow step definition
· 3.7.7.: Add
Imperative workflow definition
· 3.8: Add the
workflows keyname to the topology template definition
· 6.3: Added a
simplified way to declare a CSAR without the meta file.
· 7: Added a TOSCA workflows
section.
|
|
WDO1, Rev07
|
2016-19-05
|
Luc Boutier, FastConnect
|
· 3.5.18: Add
assertion definition
· 3.5.19: Add
condition clause definition
· 3.5.20: Leverage
condition clause in precondition definition
· 3.5.21: Leverage
condition clause as filter in step definition
· 7.2: Add
documentation and example on TOSCA normative weaving
· 7.3: Fix examples
in imperative workflows definition
|
|
WDO1, Rev08
|
2016-31-05
|
Luc Boutier,
FastConnect
|
· 7.2: Specifies
current expected declarative workflows and limitations.
|
|
WD01, Rev09
|
2016-31-05
|
Luc Boutier,
FastConnect; Matt Rutkowski, IBM
|
· 1.8: Add
description for abstract nodes and no-op nodes to the glossary
· Fixed typos,
spelling/grammar and fixed numerous broken hyperlinks.
|
