Add pagination and changes-since filter support for os-migrations API

Add pagination and changes-since filter support for os-migrations API

https://blueprints.launchpad.net/nova/+spec/ add-pagination-and-change-since-for-migration-list

This blueprint add limit and marker optional parameters to GET /os-migrations request to support pagination.

This blueprint also add changes-since optional parameters to GET /os-migrations request to support filtering response data by updated time.

Problem description

Currently, os-migrations API does not support pagination. As in large scale deployment the number of migration records can be also very large query them all can lead to performance bottleneck, it will be very useful to support pagination.

Also, os-migrations API does not support filter the migration record by last updated time. As for production deployment, the system will be up for a very long time, and the number of migration records will also be very big. It will be very useful to support filter by last update time.

Use Cases

For large scale production deployment, the administrator can use pagination and lastest updated time filter to have more efficient database query.

Proposed change

Add an API microversion that allows to get several migrations using general pagination mechanism with the help of limit and marker`optional parameters to GET /os-migrations request. And add filter with the help of `changes-since optional parameter to GET /os-migrations request.

  • marker: The last migration ID of the previous page. Displays list of migrations after “marker”.

  • limit: Maximum number of migrations to display. If limit == -1, all migrations will be displayed. If limit is bigger than osapi_max_limit option of Nova API, limit osapi_max_limit will be used instead.

Alternatives

None

Data model impact

None

REST API impact

The proposal would add API microversion for getting several migrations using general pagination mechanism. New optional parameters limit, marker, and changes-since will be added to GET /os-migrations request.

Generic request format

GET /os-migrations?limit={limit}&marker={migration_id}
  1. Get all migrations

    GET /os-migrations
    

    Response

    {
    "migrations": [
        {
            "created_at": "2012-10-29T13:42:02.000000",
            "dest_compute": "compute2",
            "dest_host": "1.2.3.4",
            "dest_node": "node2",
            "id": 1234,
            "instance_uuid": "instance_id_123",
            "new_instance_type_id": 2,
            "old_instance_type_id": 1,
            "source_compute": "compute1",
            "source_node": "node1",
            "status": "Done",
            "updated_at": "2012-10-29T13:42:02.000000"
        },
        {
            "created_at": "2013-10-22T13:42:02.000000",
            "dest_compute": "compute20",
            "dest_host": "5.6.7.8",
            "dest_node": "node20",
            "id": 5678,
            "instance_uuid": "instance_id_456",
            "new_instance_type_id": 6,
            "old_instance_type_id": 5,
            "source_compute": "compute10",
            "source_node": "node10",
            "status": "Done",
            "updated_at": "2013-10-22T13:42:02.000000"
        },
        {
            "created_at": "2013-10-22T13:45:02.000000",
            "dest_compute": "compute21",
            "dest_host": "5.6.7.8",
            "dest_node": "node21",
            "id": 5679,
            "instance_uuid": "instance_id_4561",
            "new_instance_type_id": 6,
            "old_instance_type_id": 5,
            "source_compute": "compute10",
            "source_node": "node10",
            "status": "Done",
            "updated_at": "2013-10-22T13:45:02.000000"
        }
    ]
    }
    
  2. Get no more than 2 migrations

    GET /os-migrations?limit=2
    

    Response

    {
    "migrations": [
        {
            "created_at": "2012-10-29T13:42:02.000000",
            "dest_compute": "compute2",
            "dest_host": "1.2.3.4",
            "dest_node": "node2",
            "id": 1234,
            "instance_uuid": "instance_id_123",
            "new_instance_type_id": 2,
            "old_instance_type_id": 1,
            "source_compute": "compute1",
            "source_node": "node1",
            "status": "Done",
            "updated_at": "2012-10-29T13:42:02.000000"
        },
        {
            "created_at": "2013-10-22T13:42:02.000000",
            "dest_compute": "compute20",
            "dest_host": "5.6.7.8",
            "dest_node": "node20",
            "id": 5678,
            "instance_uuid": "instance_id_456",
            "new_instance_type_id": 6,
            "old_instance_type_id": 5,
            "source_compute": "compute10",
            "source_node": "node10",
            "status": "Done",
            "updated_at": "2013-10-22T13:42:02.000000"
        }
    ]
    }
    
  3. Get all migrations after id=1234

    GET /os-migrations?marker=1234
    

    Response

    {
    "migrations": [
        {
            "created_at": "2013-10-22T13:42:02.000000",
            "dest_compute": "compute20",
            "dest_host": "5.6.7.8",
            "dest_node": "node20",
            "id": 5678,
            "instance_uuid": "instance_id_456",
            "new_instance_type_id": 6,
            "old_instance_type_id": 5,
            "source_compute": "compute10",
            "source_node": "node10",
            "status": "Done",
            "updated_at": "2013-10-22T13:42:02.000000"
        },
        {
            "created_at": "2013-10-22T13:45:02.000000",
            "dest_compute": "compute21",
            "dest_host": "5.6.7.8",
            "dest_node": "node21",
            "id": 5679,
            "instance_uuid": "instance_id_4561",
            "new_instance_type_id": 6,
            "old_instance_type_id": 5,
            "source_compute": "compute10",
            "source_node": "node10",
            "status": "Done",
            "updated_at": "2013-10-22T13:45:02.000000"
        }
    ]
    }
    

Request format

GET /os-migrations?changes-since=2013-10-22T13:45:02.000000

Response

{
"migrations":[
    {
        "created_at": "2013-10-22T13:45:02.000000",
        "dest_compute": "compute21",
        "dest_host": "5.6.7.8",
        "dest_node": "node21",
        "id": 1234,
        "instance_uuid": "instance_id_4561",
        "new_instance_type_id": 6,
        "old_instance_type_id": 5,
        "source_compute": "compute10",
        "source_node": "node10",
        "status": "Done",
        "updated_at": "2013-10-22T13:45:02.000000"
    }
]
}

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

Reduce load on Horizon with the help of pagination and time filtering of retrieving migrations from Nova side.

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Zheng Zhenyu

Work Items

Create a new API microversion for getting several migrations using general pagination mechanism and time stamp filtering.

Dependencies

None

Testing

Would need new Tempest, functional and unit tests.

Documentation Impact

Docs needed for new API microversion and usage.

References

Creative Commons Attribution 3.0 License

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nova-specs