TOSCA Parser and Heat Translator Integration

TOSCA Parser and Heat Translator Integration

https://blueprints.launchpad.net/tacker/+spec/tosca-parser-integration

Problem description

Tacker uses a private YAML format for VNFD templates that bears a passing resemblance to TOSCA but has custom tags and far fewer capabilities. Tacker also does it’s own translation of the VNFD into a Heat template, which requires maintenance and has far fewer capabilities than other existing projects.

This spec documents the changes required in Tacker to support using tosca-parser and heat-translator instead of the existing YAML format and custom Heat template generator. Tacker will use heat-translator to create the base HOT template, and will make whatever modifications are needed to support the rapidly-evolving NFV profile.

Proposed change

There tosca-parser [1] and heat-translator [2] projects have been updated to support the TOSCA NFV Profile [3]. The tosca-parser project has also accepted a patch to allow it to be used by a server providing a pre-formatted YAML dictionary instead of a file or URL containing the template.

This spec proposes to add support for TOSCA templates by using the tosca-parser and heat-translator projects to eventually replace the custom YAML template and HOT template generation used by Tacker today.

The initial implementation will coexist with the existing Tacker YAML format, and the interfaces will remain the same. Future work will be required to separate the TOSCA template processing from the Heat driver and remove the existing template processing.

Parameters will be handled as they are today. Both tosca-parser and heat-translator accept parameter inputs to be applied to the resulting template.

Tacker will support both the tosca_simple_yaml_1_0 and tosca_simple_profile_for_nfv_1_0_0 profiles in the version field.

Tacker-specific data such as management drivers and monitoring drivers will be added to the existing NFV object definitions for use in the TOSCA template. All Tacker extensions will need to be removed from the translated ToscaTemplate before it is passed to the ToscaTranslator for conversion to HOT.

The tacker_defs.yaml file will define Tacker-specific types that are not specific to NFV profile types. The tacker_nfv_defs.yaml file will define Tacker-specific NFV types. These files will be automatically added as an import to all VNFDs when they are created, based on the version of the template. The imports must be added by the Tacker server in order to be able to specify the full path to the import file.

Sample tacker_defs.yaml

data_types:
  tosca.datatypes.tacker.Monitoring.ActionMap:
    properties:
      trigger:
        type: string
        required: true
      action:
        type: string
        required: true
      params:
        type: map
        entry_schema:
          type: string

  tosca.datatypes.tacker.Monitoring.Mechanism:
    properties:
      name:
        type: string
        required: true
      actions:
        type: list
        entry_schema:
          type: tosca.datatypes.tacker.ActionMap
      parameters:
        type: map
        entry_schema:
          type: string

policy_types:
  tosca.policies.tacker.Placement:
    derived_from: tosca.policies.Root

  tosca.policies.tacker.Monitoring:
    derived_from: tosca.policies.Root
    monitoring_params:
      type: map
      entry_schema:
        type: string

  tosca.policies.tacker.Monitoring.Failure:
    derived_from: tosca.policies.tacker.Monitoring
    action:
      type: string

  tosca.policies.tacker.Monitoring.Failure.Respawn:
    derived_from: tosca.policies.tacker.Monitoring.Failure
    action: respawn

  tosca.policies.tacker.Monitoring.Failure.Terminate:
    derived_from: tosca.policies.tacker.Monitoring.Failure
    action: log_and_kill

  tosca.policies.tacker.Monitoring.Failure.Log:
    derived_from: tosca.policies.tacker.Monitoring.Failure
    action: log

  tosca.policies.tacker.Monitoring.NoOp:
    derived_from: tosca.policies.tacker.Monitoring

  tosca.policies.tacker.Monitoring.Ping:
    derived_from: tosca.policies.tacker.Monitoring
    monitoring_params:
      count: 3
      interval: 5

  tosca.policies.tacker.Monitoring.HttpPing:
    derived_from: tosca.policies.tacker.Monitoring.Ping

group_types:
  tosca.groups.tacker.VDU:
    derived_from: tosca.groups.Root

Sample tacker_nfv_defs.yaml

node_types:
  tosca.nodes.nfv.VDU.Tacker:
    derived_from: tosca.nodes.nfv.VDU
    properties:
      image:
        type: string
      flavor:
        type: string
      availability_zone:
        type: string
      metadata:
        type: map
        entry_schema:
          type: string
      config_drive:
        type: boolean
        default: false

      placement_policy:
        type: string

      monitoring_policy:
        type: tosca.datatypes.tacker.MonitoringMechanism

      config:
        type: string

      mgmt_driver:
        type: string

      service_type:
        type: string

  tosca.nodes.nfv.CP.Tacker:
    derived_from: tosca.nodes.nfv.CP
    properties:
      management:
        type: boolean
        required: false
        default: false
      anti_spoofing_protection:
        type: boolean
        required: false

Alternatives

Tacker could continue to maintain it’s own YAML format and HOT template generation but this will put significant limitations on future capabilities.

Data model impact

Initial support for tosca-parser/heat-translator will have no data model impact. Future changes may be required to add the ability to specify multiple different management drivers for different VDUs, and to handle CSAR files.

REST API impact

None

Security impact

None

Notifications impact

None

Other end user impact

User will need to use TOSCA templates to take advantage of this capability

Performance Impact

Using tosca-parser and heat-translator will use more cycles than the home-grown solution, but the additional capabilities provided more than make up for the small increase in processing time.

Other deployer impact

The plan is to support the existing YAML format and TOSCA together through the Mitaka cycle. The existing YAML format will be deprecated in Mitaka and removed in Newton.

Developer impact

None

Implementation

Assignee(s)

Primary assignee:
bob-haddleton

Work Items

  • Develop tacker_defs.yaml file to extend the existing TOSCA NFV node definitions with the properties required by Tacker. File to be stored in tacker/vm/tosca/lib
  • Create module tacker.vm.tosca.utils to provide utility methods to manipulate the TOSCA template as needed
  • Modify the existing heat driver create_device_template_pre() method to detect a TOSCA template and invoke tosca-parser (ToscaTemplate) to pre-process the template for any syntax errors and store the resulting data in the database.
  • Modify the existing heat driver create() method to detect a TOSCA template and invoke tosca-parser (ToscaTemplate) and heat-translator (TOSCATranslator) to generate the HOT template. The generated ToscaTemplate will need to be processed to remove the Tacker-specific nodes and properties before it can be processed by TOSCATranslator to generate the HOT template.

Dependencies

  • tosca-parser 0.4.0 release is required for this feature
  • heat-translator 0.4.0 release is required for this feature

Testing

Existing tests for the heat driver will be expanded to include support for testing the create_device_template_pre() method and the create() method with TOSCA template inputs to ensure that the feature works as expected.

Documentation Impact

Documentation of the Tacker-specific extensions to the NFV Profile as defined by tacker_defs.yaml will be needed, and sample TOSCA templates will need to be provided. Devstack sample templates will also be needed.

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