5.2.3. ONAP Heat Orchestration Templates Overview

ONAP supports a modular Heat Orchestration Template design pattern, referred to as VNF Modularity.

5.2.3.1. ONAP VNF Modularity Overview

Requirement: R-69663 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF MAY be composed from one or more Heat Orchestration Templates, each of which represents a subset of the overall VNF.

The Heat Orchestration Templates can be thought of a components or modules of the VNF and are referred to as VNF Modules. During orchestration, these modules are deployed incrementally to create the complete VNF.

Requirement: R-33132 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
updated: casablanca
A VNF’s Heat Orchestration Template MAY be
1.) Base Module Heat Orchestration Template (also referred to as a
Base Module),
2.) Incremental Module Heat Orchestration Template (referred to as
an Incremental Module), or
3.) a Cinder Volume Module Heat Orchestration Template (referred to as
Cinder Volume Module).
Requirement: R-37028 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
A VNF MUST be composed of one Base Module
Requirement: R-13196 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF MAY be composed of zero to many Incremental Modules.
Requirement: R-28980 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s incremental module MAY be used for initial VNF deployment only.
Requirement: R-86926 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s incremental module MAY be used for scale out only.

A VNF’s Incremental Module that is used for scale out is deployed sometime after initial VNF deployment to add capacity.

Requirement: R-91497 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s incremental module MAY be used for both deployment and scale out.
Requirement: R-68122 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s incremental module MAY be deployed more than once, either during initial VNF deployment and/or scale out.
Requirement: R-46119 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
updated: dublin
A VNF’s Heat Orchestration Template’s Resource OS::Cinder::Volume MAY be defined in a Base Module.
Requirement: R-90748 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
updated: dublin
A VNF’s Heat Orchestration Template’s Resource OS::Cinder::Volume MAY be defined in an Incremental Module.
Requirement: R-03251 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
updated: dublin
A VNF’s Heat Orchestration Template’s Resource OS::Cinder::Volume MAY be defined in a Cinder Volume Module.

ONAP also supports the concept of an optional, independently deployed Cinder volume via a separate Heat Orchestration Templates, referred to as a Cinder Volume Module. This allows the volume to persist after a Virtual Machine (VM) (i.e., OS::Nova::Server) is deleted, allowing the volume to be reused on another instance (e.g., during a fail over activity).

Requirement: R-11200 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
A VNF’s Cinder Volume Module, when it exists, MUST be 1:1 with a Base module or Incremental module.

It is strongly recommended that Cinder Volumes be created in a Cinder Volume Module.

Requirement: R-38474 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
A VNF’s Base Module MUST have a corresponding Environment File.
Requirement: R-81725 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
A VNF’s Incremental Module MUST have a corresponding Environment File
Requirement: R-53433 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
A VNF’s Cinder Volume Module MUST have a corresponding environment file

These concepts will be described in more detail throughout the document. This overview is provided to set the stage and help clarify the concepts that will be introduced.

5.2.3.2. Nested Heat Orchestration Templates Overview

ONAP supports nested Heat Orchestration Templates per OpenStack specifications.

Requirement: R-36582 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s Base Module MAY utilize nested heat.
Requirement: R-56721 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s Incremental Module MAY utilize nested heat.
Requirement: R-30395 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MAY
A VNF’s Cinder Volume Module MAY utilize nested heat.

Nested templates may be suitable for larger VNFs that contain many repeated instances of the same VM type(s). A common usage pattern is to create a nested template for each VM type along with its supporting resources. The Heat Orchestration Template may then reference these nested templates either statically (by repeated definition) or dynamically (via OS::Heat::ResourceGroup).

See Nested Heat Templates for additional details.

5.2.3.3. ONAP Heat Orchestration Template Filenames

In order to enable ONAP to understand the relationship between Heat files, the following Heat file naming convention must be utilized.

In the examples below, <text> represents any alphanumeric string that must not contain any special characters and must not contain the word “base”.

Requirement: R-87485 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: static
A VNF’s Heat Orchestration Template’s file extension MUST be in the lower case format .yaml or .yml.
Requirement: R-56438 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: static
A VNF’s Heat Orchestration Template’s Nested YAML file extension MUST be in the lower case format .yaml or .yml.
Requirement: R-74304 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: static
A VNF’s Heat Orchestration Template’s Environment file extension MUST be in the lower case format .env.
Requirement: R-99646 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: static
A VNF’s YAML files (i.e, Heat Orchestration Template files and Nested files) MUST have a unique name in the scope of the VNF.

5.2.3.3.1. Base Modules

Requirement: R-81339 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: el alto
validation_mode: static

A VNF Heat Orchestration Template’s Base Module file name MUST include case insensitive ‘base’ in the filename and MUST match one of the following four formats:

1.) base_<text>.y[a]ml

2.) <text>_base.y[a]ml

3.) base.y[a]ml

4.) <text>_base_<text>.y[a]ml

where <text> MUST contain only alphanumeric characters and underscores ‘_’ and MUST NOT contain the case insensitive string base or volume.

Requirement: R-91342 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: static
A VNF Heat Orchestration Template’s Base Module’s Environment File MUST be named identical to the VNF Heat Orchestration Template’s Base Module with .y[a]ml replaced with .env.

5.2.3.3.2. Incremental Modules

Requirement: R-87247 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: el alto
validation_mode: static
VNF Heat Orchestration Template’s Incremental Module file name MUST contain only alphanumeric characters and underscores ‘_’ and MUST NOT contain the case insensitive string base.
Requirement: R-94509 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: static
A VNF Heat Orchestration Template’s Incremental Module’s Environment File MUST be named identical to the VNF Heat Orchestration Template’s Incremental Module with .y[a]ml replaced with .env.

To clearly identify the incremental module, it is recommended to use the following naming options for modules:

  • module_<text>.y[a]ml
  • <text>_module.y[a]ml
  • module.y[a]ml
  • <text>_module_<text>.y[a]ml

5.2.3.3.3. Cinder Volume Modules

Requirement: R-82732 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
A VNF Heat Orchestration Template’s Cinder Volume Module MUST be named identical to the base or incremental module it is supporting with _volume appended.
Requirement: R-589037 ../../../../../../_images/arrow-right-circle.svg
keyword: MUST
introduced: dublin
updated: el alto
validation_mode: static

A VNF Heat Orchestration Template’s Cinder Volume Module resources: section MUST only be defined using one of the following:

  • one of more OS::Cinder::Volume resources
  • one or more OS::Heat::ResourceGroup resources that call a nested YAML file that contains only OS::Cinder::Volume resources
  • a resource that calls a nested YAML file (static nesting) that contains only OS::Cinder::Volume resources
Requirement: R-31141 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: casablanca
validation_mode: static
VNF Heat Orchestration Template’s Cinder Volume Module’s Environment File MUST be named identical to the VNF Heat Orchestration Template’s Cinder Volume Module with .y[a]ml replaced with .env.

5.2.3.3.4. Nested Heat file

Requirement: R-76057 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: el alto
validation_mode: static
VNF Heat Orchestration Template’s Nested YAML file name MUST contain only alphanumeric characters and underscores ‘_’ and MUST NOT contain the case insensitive string base.
Requirement: R-70276 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST NOT
validation_mode: static
A VNF HEAT’s Orchestration Nested Template’s YAML file name MUST NOT be in the format {vm-type}.y[a]ml where {vm-type} is defined in the Heat Orchestration Template.

Examples include

  • <text>.y[a]ml
  • nest_<text>.y[a]ml
  • <text>_nest.y[a]ml
  • nest.y[a]ml
  • <text>_nest_<text>.y[a]ml

VNF Heat Orchestration Template’s Nested YAML file does not have a corresponding environment files, per OpenStack specifications.

5.2.3.4. Output Parameters

The output parameters are parameters defined in the output section of a Heat Orchestration Template. The ONAP output parameters are subdivided into three categories:

  1. ONAP Base Module Output Parameters
  2. ONAP Volume Module Output Parameters
  3. ONAP Predefined Output Parameters.

5.2.3.4.1. ONAP Base Module Output Parameters

ONAP Base Module Output Parameters are declared in the outputs: section of the VNF’s Heat Orchestration Template’s Base Module. A Base Module Output Parameter is available as an input parameter (i.e., declared in the parameters: section) to all Incremental Modules in the VNF.

A Base Module Output Parameter may be used as an input parameter in any incremental module in the VNF. Note that the parameter is not available to other VNFs.

Requirement: R-52753 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: dublin
validation_mode: none
VNF’s Heat Orchestration Template’s Base Module’s output parameter’s name and type MUST match the VNF’s Heat Orchestration Template’s incremental Module’s name and type.
Requirement: R-22608 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: SHOULD NOT
updated: dublin
validation_mode: static
When a VNF’s Heat Orchestration Template’s Base Module’s output parameter is declared as an input parameter in an Incremental Module, the parameter attribute constraints: SHOULD NOT be declared.

Additional details on ONAP Base Module Output Parameters are provided in ONAP Output Parameter Names and ONAP VNF Modularity.

5.2.3.4.2. ONAP Volume Module Output Parameters

Requirement: R-89913 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: dublin
validation_mode: static
A VNF’s Heat Orchestration Template’s Cinder Volume Module Output Parameter(s) MUST include the UUID(s) of the Cinder Volumes created in template.

A VNF’s Heat Orchestration Template’s Cinder Volume Module Output Parameter(s) are only available for the module (base or incremental) that the volume template is associated with.

Requirement: R-07443 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
updated: dublin
validation_mode: static
A VNF’s Heat Orchestration Templates’ Cinder Volume Module Output Parameter’s name and type MUST match the input parameter name and type in the corresponding Base Module or Incremental Module.
Requirement: R-20547 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: SHOULD NOT
updated: dublin
validation_mode: static
When an ONAP Volume Module Output Parameter is declared as an input parameter in a base or an incremental module Heat Orchestration Template, parameter constraints SHOULD NOT be declared.

Additional details on ONAP Base Module Output Parameters are provided in ONAP Output Parameter Names and ONAP Heat Cinder Volumes.

5.2.3.4.3. ONAP Predefined Output Parameters

ONAP will look for a small set of pre-defined Heat output parameters to capture resource attributes for inventory in ONAP. These output parameters are optional and currently only two parameters are supported. These output parameters are optional and are specified in OAM Management IP Addresses.

5.2.3.5. Support of heat stack update

ONAP does not support the use of heat stack-update command for scaling (growth/de-growth).

Requirement: R-39349 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST NOT
validation_mode: none
A VNF Heat Orchestration Template MUST NOT be designed to utilize the OpenStack heat stack-update command for scaling (growth/de-growth).
Requirement: R-43413 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: none
A VNF MUST utilize a modular Heat Orchestration Template design to support scaling (growth/de-growth).

It is important to note that ONAP only supports heat stack-update for image upgrades.

5.2.3.6. Scope of a Heat Orchestration Template

Requirement: R-59482 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST NOT
validation_mode: none
A VNF’s Heat Orchestration Template MUST NOT be VNF instance specific or cloud site specific.

ONAP provides the instance specific parameter values to the Heat Orchestration Template at orchestration time.

Requirement: R-01896 ../../../../../../_images/arrow-right-circle.svg
target: VNF
keyword: MUST
validation_mode: none
A VNF’s Heat Orchestration Template’s parameter values that are constant across all deployments MUST be declared in a Heat Orchestration Template Environment File.

5.2.3.7. ONAP VNF On-Boarding

Requirement: R-511776 ../../../../../../_images/arrow-right-circle.svg
keyword: MUST
introduced: dublin
validation_mode: static
When a VNF’s Heat Orchestration Template is ready to be on-boarded to ONAP, all files composing the VNF Heat Orchestration Template MUST be placed in a flat (i.e., non-hierarchical) directory and archived using ZIP. The resulting ZIP file is uploaded into ONAP.

The VNF’s Heat Orchestration Template’s ZIP file must include the base module YAML file (R-37028) and corresponding environment file (R-38474).

The VNF’s Heat Orchestration Template’s ZIP file MAY include

  • One or more incremental module YAML files (R-13196) and corresponding environment files (R-81725).
  • One or more volume module YAML files (R-03251) and corresponding environment files (R-53433).
  • One or more nested YAML files (R-36582, R-56721, R-30395).
  • One or more files that are retrieved via the intrinsic function get_file. The get_file function returns the content of a file into a Heat Orchestration Template. It is generally used as a file inclusion mechanism for files containing scripts or configuration files. (See Section 9.3)
Requirement: R-348813 ../../../../../../_images/arrow-right-circle.svg
keyword: MUST
introduced: dublin
validation_mode: static
The VNF’s Heat Orchestration Template’s ZIP file MUST NOT include a binary image file.