Before a migrate is carried out, we wish to check that the current state of the instance is ready for migration with a pre-check - effectively like a healthcheck.
Only once this done should we be able to trigger migrate.
Assumptions:
- Only the participants can execute a effective precheck.
- Precheck is executed before the migration, if it fail the migration will be not executed.
- User needs to receive the result of the precheck.
- Acm-runtime needs to handle the precheck fail in a different way it handles migration fail.
Solution: create a new flow for migration-precheck.
User can send the action migration-precheck POST. The user can do the action migration POST after that. The migration flow will be unchanged and backwards-compatible.
- User send migration-precheck action
- Acm-runtime set the instance in "MIGRATING-PRECHECK" deployState
- Acm-runtime sends migration-precheck message to participants
- Participant receives migration-precheck message and executes the precheck and sends the result
- Acm-runtime receives precheck-result messages from all participants
- Acm-runtime shows this result into the stateChangeResult (deployState will be in "DEPLOYED" state)
- NO_ERROR: means the migration is valid
- NOT_VALID: means the migration is not valid (is better do no create confusion wit FAILED)
How the user can send the action migration-precheck POST?
Below the list of solutions:
- parameter in POST action: {{address}}:{{port}}/onap/policy/clamp/acm/v2/compositions/{{compositionId}}/instances?precheck=true
- new filed into the Body:
name: DemoInstance0
version: 1.0.1
compositionId: {{composition1Id}}
instanceId: {{instanceId}}
compositionTargetId: {{composition2Id}}
precheck: true