Pagination for hypervisor

https://blueprints.launchpad.net/nova/+spec/pagination-for-hypervisor

This spec is proposed to support pagination for hypervisor.

Problem description

When there are thousands of compute nodes, it would be slow to get the whole hypervisor list, and it is bad for user experience to display thousands of items in a table in horizon.

Use Cases

• Get paginated compute nodes list when there are too many items.

Proposed change

Changes are going to be in the following places:

• New DB api compute_node_get_all_by_filters will be added with params filters, limit and marker, so other filter methods(compute_node_search_by_hypervisor, etc) also can be refactored to use this new db method.

• New compute node object get_by_filters method will be added which calls the new db api compute_node_get_all_by_filters.

• Compute api compute_node_get_all will be refactored.

• REST API microversion will be added for hypervisors list to accept pagination request.

Alternatives

None

Data model impact

None

REST API impact

New Hypervisors list API to support pagination:

request:

GET /v2.1/{tenant_id}/os-hypervisors?marker=2&limit=1

reponse:

{
  "hypervisors": [
    {
      "hypervisor_hostname": "fake-mini",
      "id": 3,
      "state": "up",
      "status": "enabled"
    }
  ]
}

Security impact

None.

Notifications impact

None

Other end user impact

None

Performance Impact

Reduce load on horizon with help of pagination of retrieving hypervisors from Nova side.

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

liyingjun

Work Items

1. Change db api to support pagination params.

2. Add compute node object method and refactor compute api.

3. Add REST API microversion.

Dependencies

None

Testing

The changes will be exercised through unit tests.

Documentation Impact

New REST API microversion will be added.

References

None