Support get volume metadata summary

https://blueprints.launchpad.net/cinder/+spec/metadata-for-volume-summary

Support get volumes’ metadata through volume summary API.

Problem description

Currently, Cinder supports filter volumes with metadata. But in some case, users don’t know what metadata all the volumes contain or what metadata is valid to filter volumes. Then users need to show the volumes one by one to get the correct metadata, this is really a heavy and unfriendly way. Imaging that if there are hundreds of volumes, admin users will take a very long time to query all metadata.

Use Cases

1. For users, they can get all the metadata easily just through one API request. 2. For dashboard, such as Horizon, it can use this metadata information to show end users a dropdown list.

Proposed change

  1. DB layer change:

    All the volumes’ metadata can be got by the sql query.

  2. API layer change:

    Add a new micro version. Add “metadata” to volume-summary API response body. The body will be like:

    "metadata": {"key1": ["value1"],"key2": ["value2", "value3"]}

Alternatives

Leave as it is. Let the operators get volumes metadata by themselves through some peripheral ways. Such as, create a script to call volume-list-detail API and then analyse the result one by one.

Data model impact

None

REST API impact

A new microversion will be created.

Cinder-client impact

Now both OpenStackClient and CinderClient don’t support volume-summary command. We can add them as well.

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

There is a little performance influence about volume-summary API since a new sql query action will be added.

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

wangxiyuan(wangxiyuan@huawei.com)

Work Items

  • Add a new microversion.

  • Add volumes’ metadata to the volume-summary API’s response body.

  • Add client side support.

Dependencies

None

Testing

  • Add unit tests.

Documentation Impact

Update API documentation.

References

None