cinder-specs/specs/juno/support-reset-state-for-backup.rst

Backup State Reset API

Include the URL of your launchpad blueprint:

https://blueprints.launchpad.net/cinder/+spec/support-reset-state-for-backup

Provide an API to to reset the state of a backup being stucked in creating or restoring.

Problem description

Since there are volume reset-state function and snapshot reset-state function, backup also needs reset-state as well. When creating or restoring backup, it may leave backup stucked in creating or restoring status due to database down or rabbitmq down, etc.. Currently we could only solve these problems by restarting cinder-backup. This bp is to another mean for administrators to solve these problems by calling backup reset state API.

1. Resetting status from creating/restoring to available

1. restoring --> available Directly change the backup status to 'error', because the backup data is already existed in storage backend.
2. creating --> available Use backup-create routine as an example to illustrate what benefit we can get from backup-reset function. Backup-create routine first backup volume and metadatas, and then update the status of volume and backup. If database just went down after update the volume's status to 'available', leaving the backup's status to be 'creating' without having methods to deal with through API.

If we have reset-state API and resetting status from creating to available, we first verify whether the backup is ok on storage backend. If so, we change backup status from creating to available. If not, we throw an exception and change backup status from creating to error.

2. Resetting status from creating/restoring to error Directly change the backup status to 'error' without restart cinder-backup.

Use Cases

Proposed change

A new API function and corresponding cinder command will be added to reset the status of backups.

The initial proposal is to provide a method for administrator to handle the backup item stucked in status like creating or restoring.

Alternatives

Login in the cinder database, use the following update sql to change the backup item.

update backups set status='some status' where id='xxx-xxx-xxx-xxx';

Data model impact

None

REST API impact

Add a new REST API to reset backup states:

• POST /v2/{tenant_id}/backups/{id}/action

JSON request schema definition:

'backup-reset_status': {
    'status': 'available'
}

Normal http response code:

202

Expected error http response code:

400

Security impact

None

Notifications impact

None

Other end user impact

A new command, backup-reset-state, will be added to python-cinderclient. This command mirrors the underlying API function.

Resetting the status of a backup can be performed by: $ cinder backup-reset-state --state <state> <backup>

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

ling-yun

Work Items

• Implement REST API
• Implement cinder client functions
• Implement cinder command

Dependencies

None

Testing

None

Documentation Impact

The cinder client documentation will need to be updated to reflect the new command.

The cinder API documentation will need to be updated to reflect the REST API changes.

References

None