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 adds limit and marker optional parameters to GET /os-migrations request to support pagination.

This blueprint also adds changes-since optional parameter to GET /os-migrations request to support filtering response data by last 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 and querying them all can lead to performance bottleneck, it will be very useful to support pagination.

Also, os-migrations API does not support filtering 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 updated time.

Use Cases

For large scale production deployment, the administrator can use pagination and last 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 UUID of the previous page. Displays list of migrations after “marker”.

  • limit: Maximum number of migrations to display. If limit is bigger than [api]/max_limit option of Nova API, limit [api]/max_limit will be used instead.

For multiple cells, we could have migrations with same ID, the migration ID as pagination marker won’t work. Currently, the migration record has a uuid column on it 1, we just need add the migration UUID field in the response, and the migration UUID needs to be the pagination marker.

We propose to merge sort the results in compute api code once we get the results back from all of the multiple cells, and results are sorted in descending order by [‘created_at’, ‘id’] keys.

Also, since we are going to add the uuid field to the response for the os-migrations API, we will also take this opportunity to add the migration uuid to the response for the GET /servers/{server_id}/migrations/{migration_id} and GET /servers/{server_id}/migrations server migrations APIs.

Alternatives

None

Data model impact

A database index will be added on migrations.updated_at to improve the performance of filtering migrations by ‘changes-since’ parameter.

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_uuid}
  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": 1,
            "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",
            "uuid": "12341d4b-346a-40d0-83c6-5f4f6892b650"
        },
        {
            "created_at": "2013-10-22T13:42:02.000000",
            "dest_compute": "compute20",
            "dest_host": "5.6.7.8",
            "dest_node": "node20",
            "id": 2,
            "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",
            "uuid": "56781d4b-346a-40d0-83c6-5f4f6892b650"
        },
        {
            "created_at": "2013-10-22T13:45:02.000000",
            "dest_compute": "compute21",
            "dest_host": "5.6.7.8",
            "dest_node": "node21",
            "id": 3,
            "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",
            "uuid": "56791d4b-346a-40d0-83c6-5f4f6892b650"
        }
    ]
    }
    
  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": 1,
            "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",
            "uuid": "12341d4b-346a-40d0-83c6-5f4f6892b650"
        },
        {
            "created_at": "2013-10-22T13:42:02.000000",
            "dest_compute": "compute20",
            "dest_host": "5.6.7.8",
            "dest_node": "node20",
            "id": 2,
            "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",
            "uuid": "56781d4b-346a-40d0-83c6-5f4f6892b650"
        }
    ],
    "migrations_links": [
        {
            "href": "https://openstack.example.com/v2.1/os-migrations?limit=2&marker=56781d4b-346a-40d0-83c6-5f4f6892b650",
            "rel": "next"
        }
    ]
    }
    
  3. Get all migrations after uuid=12341d4b-346a-40d0-83c6-5f4f6892b650

    GET /os-migrations?marker=12341d4b-346a-40d0-83c6-5f4f6892b650
    

    Response

    {
    "migrations": [
        {
            "created_at": "2013-10-22T13:42:02.000000",
            "dest_compute": "compute20",
            "dest_host": "5.6.7.8",
            "dest_node": "node20",
            "id": 2,
            "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",
            "uuid": "56781d4b-346a-40d0-83c6-5f4f6892b650"
        },
        {
            "created_at": "2013-10-22T13:45:02.000000",
            "dest_compute": "compute21",
            "dest_host": "5.6.7.8",
            "dest_node": "node21",
            "id": 3,
            "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",
            "uuid": "56791d4b-346a-40d0-83c6-5f4f6892b650"
        }
    ]
    }
    
  4. Get all migrations after changes-since=2013-10-22T13:45:02.000000

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

Note

The provided time should be an ISO 8061 formatted time. ex 2013-10-22T13:45:02.000000, 2017-10-18T16:06:59Z

Response

{
"migrations":[
    {
        "created_at": "2013-10-22T13:45:02.000000",
        "dest_compute": "compute21",
        "dest_host": "5.6.7.8",
        "dest_node": "node21",
        "id": 3,
        "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",
        "uuid": "56791d4b-346a-40d0-83c6-5f4f6892b650"
    }
]
}

Security impact

None

Notifications impact

None

Other end user impact

Python-novaclient will be modified to handle the new microversion for migration pagination support.

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Yikun Jiang

Other contributors:

Zhenyu Zheng

Work Items

  • Create a new API microversion for getting several migrations using general pagination mechanism and time stamp filtering and adding a migration UUID field in the response.

  • Modify the Nova client to handle the new microversion for migration pagination support.

Dependencies

None

Testing

Would need new in-tree functional and unit tests.

Documentation Impact

Docs needed for new API microversion and usage.

References

1

Add uuid to migration table: https://review.openstack.org/#/c/496933/

History

Revisions

Release Name

Description

Newton

Proposed

Queens

Re-proposed

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