ACM Instance Migration (WIP)

Owned by Saul Gill
Last updated: Sept 21, 2023 by Francesco Fiora
3 min read

This page contains details of planning and implementation of the migration functionality for instances in ACM-R. Rest interface users will be able to call a new endpoint in order to trigger the moving/migration of an instance from a source composition definition to a target composition definition. Calls to migrate the instance will take place on an instance-by-instance basis. The caller will have to supply the following parameters when making the call to migrate an instance.

  • Source Composition Definition Id - The Id of the composition that the instance is currently based on.

  • Target Composition Definition Id - The Id of the composition that the instance is to be migrated to.

  • Instance Id - The Id of the instance that the caller wishes to migrate.

This operation will only be possible if:

  • the source composition is primed

  • the target composition is primed and contains the same element definitions present in the source composition

  • the instance is deployed and based on the the source composition

Migration Sequence Diagram

Note: The functionality for the upload of a new composition definition already exists





End point, fail and rollback

Solution 1

Migrate using a new endpoint:
PUT /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}/migrate

{
    compositionTarget = "{{target_composition_id}}"
}

After instance has been migrated successfully, it could be retrieved using:
GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances/{{instance_id}}

In success scenario, is it possible to revert the migration, using the same endpoint with composition id inverted.

If migration fail, the instance is still based to {{source_composition_id}} with deployOrder "MIGRATING" and stateChangeResult "FAILED". In this scenario, is it possible to retry or rollback the migration.

Retry and TimeOut are supported.

Rollback:
PUT /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}/migrate

{
    rollback = "true",
    compositionTarget = "{{target_composition_id}}"
}

Solution 2

Migrate using change state endpoint:
PUT /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}

{
    deployOrder = "MIGRATE",
    compositionTarget = "{{target_composition_id}}"
}

After instance has been migrated successfully, it could be retrieved using:
GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances/{{instance_id}}

In success scenario, is it possible to revert the migration, using the same endpoint with composition id inverted.

If migration fail, the instance is still based to {{source_composition_id}} with deployOrder "MIGRATING" and stateChangeResult "FAILED". In this scenario, is it possible to retry or rollback the migration.

Retry and TimeOut are supported.

Rollback:
PUT /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}

{
    deployOrder = "MIGRATION_ROLLBACK",
    compositionTarget = "{{target_composition_id}}"
}

Solution 3

Migrate using update endpoint:
POST /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}

Body
name: ExampleInstance0 version: 1.0.1 compositionId: {{compositionId}} compositionTarget: {{target_composition_id}} elements:   709c62b3-8918-41b9-a747-d21eb79c6c23:     id: 709c62b3-8918-41b9-a747-d21eb79c6c23     definition:       name: onap.policy.clamp.ac.element.ExampleAutomationCompositionElement       version: 1.2.3     properties:     propertyExample: new value

After instance has been migrated successfully, it could be retrieved using:
GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances/{{instance_id}}

In success scenario, is it possible to revert the migration, using the same endpoint with old properties values and composition id inverted.

If migration fail, the instance is still based to {{source_composition_id}} with deployState "MIGRATING" and stateChangeResult "FAILED". In this scenario, is it possible to retry or rollback the migration.

Retry and TimeOut are supported.

Rollback:
POST /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}

Body
name: ExampleInstance0 version: 1.0.1 compositionId: {{compositionId}} compositionTarget: {{target_composition_id}} rollback: true elements:   709c62b3-8918-41b9-a747-d21eb79c6c23:     id: 709c62b3-8918-41b9-a747-d21eb79c6c23     definition:       name: onap.policy.clamp.ac.element.ExampleAutomationCompositionElement       version: 1.2.3     properties:     propertyExample: old value

Final solution

  • Migrate using update endpoint:
    POST /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances
    "compositionTargetId" and new properties values will be saved in DB and available during migration operation.

Body
name: ExampleInstance0 version: 1.0.1 instanceId: {{instanceId}} compositionId: {{compositionId}} compositionTargetId: {{target_composition_id}} elements:   709c62b3-8918-41b9-a747-d21eb79c6c23:     id: 709c62b3-8918-41b9-a747-d21eb79c6c23     definition:       name: onap.policy.clamp.ac.element.ExampleAutomationCompositionElement       version: 1.2.3     properties:     propertyExample: new value

  • New MIGRATE message to be sent over Kafka to participant

  • During migration operation, the instance will be available to retrieve by source and target composition:
    GET /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances
    GET /onap/policy/clamp/acm/v2/compositions/{{source_composition_id}}/instances/{{instance_id}}
    GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances/{{instance_id}}

Body

Note: during migration the instance instance_id is not in target_composition_id yet, so that instance will be not available in "GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances".

  • After instance has been migrated successfully, it will be retrieved using:
    GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances
    GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances/{{instance_id}}

Body

Note: The endpoint "GET /onap/policy/clamp/acm/v2/compositions/{{target_composition_id}}/instances/{{instance_id}}" is the suggested endpoint to use for checking the migration result.

  • AutomationCompositionElementListener altered to allow participant to listen for migrate message:
    void migrate(UUID instanceId, AcElementDeploy element, UUID compositionTargetId, Map<String, Object> properties) throws PfModelException;

  • If migration fail, the instance is still based to {{source_composition_id}} with deployState "MIGRATING" and stateChangeResult "FAILED". In this scenario the user will be allowed to undeploy and delete the instance.