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
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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
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Requirement: R-37028
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A VNF MUST be composed of one Base Module |
Requirement: R-13196
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A VNF MAY be composed of zero to many Incremental Modules. |
Requirement: R-28980
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A VNF’s incremental module MAY be used for initial VNF deployment only. |
Requirement: R-86926
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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
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A VNF’s incremental module MAY be used for both deployment and scale out. |
Requirement: R-68122
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A VNF’s incremental module MAY be deployed more than once, either during initial VNF deployment and/or scale out. |
Requirement: R-46119
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A VNF’s Heat Orchestration Template’s Resource |
Requirement: R-90748
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A VNF’s Heat Orchestration Template’s Resource |
Requirement: R-03251
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A VNF’s Heat Orchestration Template’s Resource |
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
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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
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A VNF’s Base Module MUST have a corresponding Environment File. |
Requirement: R-81725
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A VNF’s Incremental Module MUST have a corresponding Environment File |
Requirement: R-53433
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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
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A VNF’s Base Module MAY utilize nested heat. |
Requirement: R-56721
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A VNF’s Incremental Module MAY utilize nested heat. |
Requirement: R-30395
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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
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A VNF’s Heat Orchestration Template’s file extension MUST
be in the lower case format |
Requirement: R-56438
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A VNF’s Heat Orchestration Template’s Nested YAML file extension MUST
be in the lower case format |
Requirement: R-74304
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A VNF’s Heat Orchestration Template’s Environment file extension MUST
be in the lower case format |
Requirement: R-99646
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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
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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:
where |
Requirement: R-91342
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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 |
5.2.3.3.2. Incremental Modules
Requirement: R-87247
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VNF Heat Orchestration Template’s Incremental Module file name
MUST contain only alphanumeric characters and underscores
‘_’ and MUST NOT contain the case insensitive string |
Requirement: R-94509
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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 |
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
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A VNF Heat Orchestration Template’s Cinder Volume Module MUST
be named identical to the base or incremental module it is supporting with
|
Requirement: R-589037
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A VNF Heat Orchestration Template’s Cinder Volume Module
|
Requirement: R-31141
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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 |
5.2.3.3.4. Nested Heat file
Requirement: R-76057
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VNF Heat Orchestration Template’s Nested YAML file name MUST contain
only alphanumeric characters and underscores ‘_’ and
MUST NOT contain the case insensitive string |
Requirement: R-70276
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A VNF HEAT’s Orchestration Nested Template’s YAML file name MUST NOT
be in the format |
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:
ONAP Base Module Output Parameters
ONAP Volume Module Output Parameters
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
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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
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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 |
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
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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
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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
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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
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A VNF Heat Orchestration Template MUST NOT be designed to utilize the
OpenStack |
Requirement: R-43413
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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
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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
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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
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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
. Theget_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
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The VNF’s Heat Orchestration Template’s ZIP file MUST NOT include a binary image file. |