path: root/docs/Chapter5/Heat/ONAP Heat Orchestration Template Format.rst

.. Licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
.. Copyright 2017 AT&T Intellectual Property.  All rights reserved.

.. _ONAP Heat Orchestration Template Format:

ONAP Heat Orchestration Template Format
------------------------------------------------

As stated in the previous section, Heat Orchestration templates must be
defined in YAML.

YAML rules include:

 - Tabs are not allowed, use spaces ONLY

 - You must indent your properties and lists with 1 or more spaces

 - All Resource IDs and resource property parameters are
   case-sensitive. (e.g., "ThIs", is not the same as "thiS")

Heat Orchestration Template Structure
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Heat Orchestration template structure follows the following format,
as defined by OpenStack at
https://docs.openstack.org/developer/heat/template_guide/hot_spec.html

.. code-block:: yaml

  heat_template_version: <date>

  description:
    # a description of the template

  parameter_groups:
    # a declaration of input parameter groups and order

  parameters:
    # declaration of input parameters

  resources:
    # declaration of template resources

  outputs:
    # declaration of output parameters

  conditions:
    # declaration of conditions

heat_template_version
~~~~~~~~~~~~~~~~~~~~~~~


.. req::
    :id: R-27078
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration template **MUST** contain
    the section "heat_template_version:".

The section "heat_template_version:" must be set to a date
that is supported by the OpenStack environment.

description
~~~~~~~~~~~~


.. req::
    :id: R-39402
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template **MUST**
    contain the section "description:".

parameter_groups
~~~~~~~~~~~~~~~~~~~~~~

A VNF Heat Orchestration template may
contain the section "parameter_groups:".

parameters
~~~~~~~~~~~~~~~~~~~~~~

.. req::
    :id: R-35414
    :target: VNF
    :keyword: MUST

    A VNF Heat Orchestration's template **MUST**
    contain the section "parameters:".


.. code-block:: yaml

  parameters:

    <param name>:

      type: <string | number | json | comma_delimited_list | boolean>

      label: <human-readable name of the parameter>

      description: <description of the parameter>

      default: <default value for parameter>

      hidden: <true | false>

      constraints:

        <parameter constraints>

      immutable: <true | false>

This section allows for
specifying input parameters that have to be provided when instantiating
the template. Each parameter is specified in a separate nested block
with the name of the parameters defined in the first line and additional
attributes (e.g., type, label) defined as nested elements.


.. req::
    :id: R-90279
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration template's parameter **MUST**
    be used in a resource with the exception of the parameters
    for the OS::Nova::Server resource property availability_zone.

.. req::
    :id: R-91273
    :target: VNF
    :keyword: MAY NOT

    A VNF Heat Orchestration's template's parameter for
    the OS::Nova::Server resource property availability_zone
    **MAY NOT** be used in any OS::Nova::Resource.

That is, the parameter associated with the property 'availability_zone'
maybe declared but not used in a resource.

<param name>
+++++++++++++

The name of the parameter.


.. req::
    :id: R-25877
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's parameter
    name (i.e., <param name>) **MUST** contain only
    alphanumeric characters and underscores ('_').

type
++++


.. req::
    :id: R-36772
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's parameter
    **MUST** include the attribute "type:".

.. req::
    :id: R-11441
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's parameter
    type **MUST** be one of the following values: "string",
    "number", "json", "comma_delimited_list" or "boolean".

label
++++++


.. req::
    :id: R-32094
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template parameter
    declaration **MAY** contain the attribute "label:".

description
+++++++++++++


.. req::
    :id: R-44001
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template parameter
    declaration **MUST** contain the attribute "description".

Note that the parameter attribute "description:" is an OpenStack
optional attribute that provides a description of the parameter.
ONAP implementation requires this attribute.

default
++++++++


.. req::
    :id: R-90526
    :target: VNF
    :keyword: MUST

    A VNF Heat Orchestration Template parameter
    declaration **MUST** not contain the default attribute.

.. req::
    :id: R-26124
    :target: VNF
    :keyword: MUST

    If a VNF Heat Orchestration Template parameter
    requires a default value, it **MUST** be enumerated in the environment file.

Note that the parameter attribute "default:" is an OpenStack
optional attribute that declares the default value of the
parameter. ONAP implementation prohibits the use of this attribute.

hidden
+++++++


.. req::
    :id: R-32557
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template parameter
    declaration **MAY** contain the attribute "hidden:".

The parameter attribute "hidden:" is an OpenStack optional
attribute that defines whether the parameters should be
hidden when a user requests information about a stack
created from the template. This attribute can be used
to hide passwords specified as parameters.

constraints
++++++++++++

The parameter attribute "constraints:" is an OpenStack optional
attribute that defines a list of constraints to apply to the parameter.


.. req::
    :id: R-88863
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's parameter defined as
    type "number" **MUST** have a parameter constraint of "range" or
    "allowed_values" defined.

.. req::
    :id: R-40518
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's parameter defined as
    type "string" **MAY** have a parameter constraint defined.

.. req::
    :id: R-96227
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's parameter defined as
    type "json" **MAY** have a parameter constraint defined.

.. req::
    :id: R-79817
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's parameter defined as
    type "comma_delimited_list" **MAY** have a parameter constraint defined.

.. req::
    :id: R-06613
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's parameter defined as
    type "boolean" **MAY** have a parameter constraint defined.

.. req::
    :id: R-00011
    :target: VNF
    :keyword: MUST NOT

    A VNF's Heat Orchestration Template's Nested YAML files
    parameter's **MUST NOT** have a parameter constraint defined.

The constraints block of a parameter definition defines additional
validation constraints that apply to the value of the parameter.
The parameter values provided in the VNF Heat Orchestration Template
are validated against the constraints at instantiation time.
The stack creation fails if the parameter value doesn't comply to
the constraints.

The constraints are defined as a list with the following syntax

.. code-block:: yaml

  constraints:

    <constraint type>: <constraint definition>

    description: <constraint description>

..

**<constraint type>** Provides the type of constraint to apply.
The list of OpenStack supported constraints can be found at
https://docs.openstack.org/heat/latest/template_guide/hot_spec.html .

**<constraint definition>** provides the actual constraint.
The syntax and constraint is dependent of the <constraint type> used.

**description** is an optional attribute that provides a description of the
constraint. The text is presented to the user when the value the user
defines violates the constraint. If omitted, a default validation
message is presented to the user.

Below is a brief overview of the "range" and "allowed values" constraints.
For complete details on constraints, see
https://docs.openstack.org/heat/latest/template_guide/hot_spec.html#parameter-constraints

**range**

range: The range constraint applies to parameters of type: number.
It defines a lower and upper limit for the numeric value of the
parameter. The syntax of the range constraint is

.. code-block:: yaml

    range: { min: <lower limit>, max: <upper limit> }

..

It is possible to define a range constraint with only a lower
limit or an upper limit.

**allowed_values**

allowed_values: The allowed_values constraint applies to parameters of
type \"string\" or type \"number\". It specifies a set of possible
values for a parameter. At deployment time, the user-provided value
for the respective parameter must match one of the elements of the
list. The syntax of the allowed_values constraint is

.. code-block:: yaml

    allowed_values: [ <value>, <value>, ... ]

    Alternatively, the following YAML list notation can be used

    allowed_values:

    - <value>

    - <value>

    - ...

. .

immutable
++++++++++++


.. req::
    :id: R-22589
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template parameter declaration
    **MAY** contain the attribute "immutable:".

The parameter attribute \"immutable:\" is an OpenStack optional
attribute that defines whether the parameter is updatable. A Heat
Orchestration Template stack update fails if immutable is set to
true and the parameter value is changed.  This attribute
\"immutable:\" defaults to false.

.. _resources:

resources
~~~~~~~~~~~~


.. req::
    :id: R-23664
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration template **MUST** contain
    the section "resources:".

.. req::
    :id: R-90152
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's "resources:"
    section **MUST** contain the declaration of at least one resource.

.. req::
    :id: R-40551
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's Nested YAML files
    **MAY** contain the section "resources:".

Each resource is defined as a
separate block in the resources section with the following syntax.

.. code-block:: yaml

  resources:

    <resource ID>:

      type: <resource type>

      properties:

        <property name>: <property value>

      metadata:

        <resource specific metadata>

      depends_on: <resource ID or list of ID>

      update_policy: <update policy>

      deletion_policy: <deletion policy>

      external_id: <external resource ID>

      condition: <condition name or expression or boolean>



resource ID
+++++++++++++


.. req::
    :id: R-75141
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's resource name
    (i.e., <resource ID>) **MUST** only contain alphanumeric
    characters and underscores ('_').

.. req::
    :id: R-16447
    :target: VNF
    :keyword: MUST

    A VNF's <resource ID> **MUST** be unique across all
    Heat Orchestration Templates and all HEAT Orchestration Template
    Nested YAML files that are used to create the VNF.

Note that a VNF can be composed of one or more Heat Orchestration Templates.

Note that OpenStack requires the <resource ID> to be unique to the
Heat Orchestration Template and not unique across all Heat
Orchestration Templates the compose the VNF.

type
+++++

The resource attribute \"type:\" is an OpenStack required
attribute that defines the resource type, such as
OS::Nova::Server or OS::Neutron::Port.

The resource attribute \"type:\" may specify a VNF HEAT
Orchestration Template Nested YAML file.


.. req::
    :id: R-53952
    :target: VNF
    :keyword: MUST NOT

    A VNF's Heat Orchestration Template's Resource
    **MUST NOT** reference a HTTP-based resource definitions.

.. req::
    :id: R-71699
    :target: VNF
    :keyword: MUST NOT

    A VNF's Heat Orchestration Template's Resource
    **MUST NOT** reference a HTTP-based Nested YAML file.

properties
+++++++++++++

The resource attribute \"properties:\" is an OpenStack optional
attribute that provides a list of resource-specific properties.
The property value can be provided in place, or via a function
(e.g., `Intrinsic functions <https://docs.openstack.org/developer/heat/template_guide/hot_spec.html#hot-spec-intrinsic-functions>`__).


.. req::
    :id: R-10834
    :target: VNF
    :keyword: MUST
    :test: no test found
    :test_case: no test found
    :test_file: no test found

    If a VNF Heat Orchestration Template resource attribute
    "property:" uses a nested "get_param", one level of nesting is
    supported and the nested "get_param" **MUST** reference an index.

metadata
++++++++++

The resource attribute \"metadata:\" is an OpenStack optional attribute.


.. req::
    :id: R-97199
    :target: VNF
    :keyword: MUST

    A VNF's Heat Orchestration Template's OS::Nova::Server
    resource **MUST** contain the attribute "metadata".

Section 5.4 contains the OS::Nova::Server mandatory and optional metadata.

depends_on
+++++++++++

The resource attribute \"depends_on:\" is an OpenStack optional
attribute.
See `OpenStack documentation <https://docs.openstack.org/developer/heat/template_guide/hot_spec.html#hot-spec-resources-dependencies>`__
for additional details.


.. req::
    :id: R-46968
    :target: VNF
    :keyword: MAY

    VNF's Heat Orchestration Template's Resource **MAY**
    declare the attribute "depends_on:".

update_policy
++++++++++++++


.. req::
    :id: R-63137
    :target: VNF
    :keyword: MAY

    VNF's Heat Orchestration Template's Resource **MAY**
    declare the attribute "update_policy:".

deletion_policy
+++++++++++++++++++


.. req::
    :id: R-43740
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's Resource
    **MAY** declare the attribute "deletion_policy:".

If specified, the \"deletion_policy:\" attribute for resources
allows values 'Delete', 'Retain', and 'Snapshot'.
Starting with heat_template_version 2016-10-14, lowercase
equivalents are also allowed.

The default policy is to delete the physical resource when
deleting a resource from the stack.

external_id
++++++++++++


.. req::
    :id: R-78569
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration Template's Resouce **MAY**
    declare the attribute "external_id:".

This attribute allows for specifying the resource_id for an
existing external (to the stack) resource. External resources
cannot depend on other resources, but we allow other resources to
depend on external resource. This attribute is optional.
Note: when this is specified, properties will not be used for
building the resource and the resource is not managed by Heat.
This is not possible to update that attribute. Also,
resource won't be deleted by heat when stack is deleted.


condition
+++++++++++

The resource attribute \"condition:\" is an OpenStack optional attribute.

Support for the resource condition attribute was added
in the Newton release of OpenStack.

outputs
~~~~~~~~~


.. req::
    :id: R-36982
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration template **MAY**
    contain the "outputs:" section.

This section allows for specifying output parameters
available to users once the template has been instantiated. If the
section is specified, it will need to adhere to specific requirements.
See :ref:`Output Parameters` and
:ref:`ONAP Output Parameter Names` for additional details.

Environment File Format
^^^^^^^^^^^^^^^^^^^^^^^^^^

The environment file is a yaml text file.
(https://docs.openstack.org/developer/heat/template_guide/environment.html)


.. req::
    :id: R-86285
    :target: VNF
    :keyword: MUST

    The VNF Heat Orchestration Template **MUST** have a corresponding
    environment file, even if no parameters are required to be enumerated.

The use of an environment file in OpenStack is optional.
In ONAP, it is mandatory.


.. req::
    :id: R-03324
    :target: VNF
    :keyword: MUST

    The VNF Heat Orchestration Template **MUST** contain the
    "parameters" section in the environment file.

.. req::
    :id: R-68198
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration template's Environment File's
    "parameters:" section **MAY** enumerate parameters.

ONAP implementation requires the parameters section in the
environmental file to be declared. The parameters section
contains a list of key/value pairs.


.. req::
    :id: R-59930
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration template's Environment
    File's **MAY** contain the "parameter_defaults:" section.

The "parameter_defaults:" section contains default parameters
that are passed to all template resources.


.. req::
    :id: R-46096
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration template's Environment File's
    **MAY** contain the "encrypted_parameters:" section.

The "encrypted_parameters:" section contains a list of encrypted parameters.


.. req::
    :id: R-24893
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration template's Environment File's
    **MAY** contain the "event_sinks:" section.

The "event_sinks:" section contains the list of endpoints that would
receive stack events.


.. req::
    :id: R-42685
    :target: VNF
    :keyword: MAY

    A VNF's Heat Orchestration template's Environment File's
    **MAY** contain the "parameter_merge_strategies:" section.

The "parameter_merge_strategies:" section provides the merge strategies
for merging parameters and parameter defaults from the environment file.


.. req::
    :id: R-67231
    :target: VNF
    :keyword: MUST NOT

    A VNF's Heat Orchestration template's Environment File's **MUST NOT**
    contain the "resource_registry:" section.

ONAP implementation does not support the Environment File
resource_registry section. The resource_registry section
allows for the definition of custom resources.

SDC Treatment of Environment Files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Parameter values enumerated in the environment file are used by SDC as
the default value. However, the SDC user may use the SDC GUI to
overwrite the default values in the environment file.

SDC generates a new environment file for distribution to MSO based on
the uploaded environment file and the user provided GUI updates. The
user uploaded environment file is discarded when the new file is
created.

ONAP has requirements for what parameters must be enumerated in the
environment file and what parameter must not be enumerated in the
environment file. See :ref:`Output Parameters` and
:ref:`ONAP Heat Resource ID and Parameter Naming Convention` for more details.