List/show all server migration types

https://blueprints.launchpad.net/nova/+spec/list-show-all-server-migration-types

The following APIs are used to list server migrations and show a server migration. But they can list or show live migration(s) only. So this blueprint enables us to list and show other migration types (‘evacuation’, ‘resize’, ‘migration’).

  • GET /servers/{server_id}/migrations

  • GET /servers/{server_id}/migrations/{migration_id}

Problem description

To abort cold migrations [1], administrators have to list/show cold migrations. But curently they can list/show live migrations only. (The ‘os-migrations’ API is deprecated, so administrators should not use it.)

Use Cases

Operators want to list all migrations in the cloud to take any action against them [1].

Proposed change

Modify the following existing 2 APIs for live-migration to list and show other migration types (‘evacuation’, ‘resize’, ‘migration’).

  • GET /servers/{server_id}/migrations

  • GET /servers/{server_id}/migrations/{migration_id}

The former API returns in-progress migrations. The latter API returns 404 error if the specified migration is not in progress. The behavior is retained as it is.

Migration status transitions are as follows:

  • Migration/resize

    • ‘pre-migrating’ –> ‘migrating’ –> ‘post-migrating’ –> ‘finished’

  • Confirm resize

    • ‘finished’ –> ‘confirming’ –> ‘confirmed’

  • Revert resize

    • ‘finished’ –> ‘reverting’ –> ‘reverted’

  • Evacuation

    • ‘accepted’ –> ‘pre-migrating’ –> ‘done’

  • Live migration

    • (Skip the definition)

In progress migration states are defined as follows:

  • migration/resize

    • ‘pre-migrating’, ‘migrating’, ‘post-migrating’

  • confirm resize

    • Nothing

    • ‘confirming’ is not included because it doesn’t execute disk copies.

  • revert resize

    • Nothing

    • ‘reverting’ is not included because it doesn’t execute disk copies.

  • evacuation

    • ‘accepted’, ‘pre-migrating’

  • live-migration

    • ‘queued’, ‘preparing’, ‘running’, ‘post-migrating’

    • Existing definition. They remains as it is.

Alternatives

None

Data model impact

None

REST API impact

Following changes will be introduced in a new API microversion.

  • GET /servers/{server_id}/migrations

    It lists migration in progress. The migration type can be specified as a ‘type’ query parameter to filter out results. The ‘type’ query parameter is optional. If ‘type’ parameter is not specified, all migration types are listed.

    The valid ‘type’ parameters are ‘live-migration’, ‘migration’, ‘resize’ and ‘evacuation’. If ‘type’ parameter is wrong, nova-api returns 400 error. So add badRequest(400) to error response codes.

    The ‘type’ parameter is added in the response.

    JSON response body example:

    {
    "migrations": [
        {
            "dest_host": "10.0.2.15",
            "status": "post-migrating",
            "memory_processed_bytes": null,
            "type": "migration",
            "updated_at": "2017-01-31T08:03:25.000000",
            "created_at": "2017-01-31T08:03:21.000000",
            "memory_remaining_bytes": null,
            "dest_compute": "devstack-master2",
            "id": 11,
            "source_node": "devstack-master1",
            "server_uuid": "a333ee8a-367f-4841-bdc9-c8d92a6adfe4",
            "memory_total_bytes": null,
            "dest_node": "devstack-master2",
            "disk_total_bytes": null,
            "disk_processed_bytes": null,
            "disk_remaining_bytes": null,
            "source_compute": "devstack-master1"
        }
    ]
}

  • GET /servers/{server_id}/migrations/{migration_id}

    The response codes are not modified. Show a migration which has any migration type. The ‘type’ parameter is added in the response.

    JSON response body example:

    {
    "migration": {
        "dest_host": "10.0.2.15",
        "status": "post-migrating",
        "memory_processed_bytes": null,
        "type": "migration",
        "updated_at": "2017-01-31T08:03:25.000000",
        "created_at": "2017-01-31T08:03:21.000000",
        "memory_remaining_bytes": null,
        "dest_compute": "devstack-master2",
        "id": 11,
        "source_node": "devstack-master1",
        "server_uuid": "a333ee8a-367f-4841-bdc9-c8d92a6adfe4",
        "memory_total_bytes": null,
        "dest_node": "devstack-master2",
        "disk_total_bytes": null,
        "disk_processed_bytes": null,
        "disk_remaining_bytes": null,
        "source_compute": "devstack-master1"
    }
}

    If a migration is not in progress state, it returns 404 error.

  • POST /servers/{server_id}/migrations/{migration_id}/action

    It is a “Force Migration Complete Action” API. The migration is not a ‘live-migration’, it returns 400 error instead of 404 error.

  • DELETE /servers/{server_id}/migrations/{migration_id}

    The migration is not a ‘live-migration’, it returns 400 error. It is a current behavior. (It is not changed.)

Security impact

Only Administrator can operate suggested functions. So there is no security impact.

Notifications impact

None

Other end user impact

The novaclient and openstackclient are modified to specify a migration type.

Performance Impact

None

Security impact

Only Administrator can operate suggested functions. So there is no security impact.

Notifications impact

None

Other end user impact

The novaclient and openstackclient are modified to specify a migration type.

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

natsume-takashi

Other contributors:

None

Work Items

  • Add the ‘type’ query parameter to list server migrations (‘evacuation’, ‘resize’, ‘migration’) API

  • Modify show a server migration (‘evacuation’, ‘resize’, or ‘migration’) API

  • Add the optional ‘type’ parameter in novaclient/openstackclient

  • API docs including note of the possible types

Dependencies

None

Testing

Add the following tests.

  • functional tests

  • tempest test

Documentation Impact

  • API Reference

  • CLI Reference

References

History

Revisions

Release Name

Description

Pike

Introduced