Backup driver initialization

https://blueprints.launchpad.net/cinder/+spec/backup-init

We don’t initialize Cinder Backup driver during service startup. It means that we’ve got cinder-backup service up and running even if it can’t connect to the backup storage.

Problem description

Cinder backup manager does not verify that backup driver is initialized successfully. If cinder-backup is started successfully we can create a volume backup. Such backups always will be in ‘error’ status and tenant user won’t be able to delete them.

Use Cases

Cinder backup service should be marked as ‘down’ if it can’t connect to the backup storage.

Proposed change

We should introduce for cinder backups the same mechanism as we’ve got for volume manager and drivers:

  • Introduce ‘init_host’ method in backup manager which will be called on service startup and verify that backup driver is initialized: verify driver’s configuration is correct, depends on driver, we could check connection to storage, list of available backups. etc.
  • If backup driver initialization fails, manager will mark backup service as ‘down’.

In case of initialization failure, cinder will try to do it periodically depends on ‘periodic_interval’ config option value.

Backup service should be initialized in ‘service_down_time’ time interval or will be marked as ‘down’.

Alternatives

Check for backup storage is available on backup create call. If storage is not available, remove ‘host’ field from backup object. We could try to re-schedule backup creation on the other host.

Data model impact

None

REST API impact

None

Security impact

None

Notifications impact

New notifications for backup initialization failure and success will be added.

Other end user impact

User will be able to delete backup in error state if it was not created on backend.

Performance Impact

None

Other deployer impact

New ‘backup_periodic_initialization’ and ‘backup_initialization_timeout’ config option will be added. Deployer have to enable ‘backup_periodic_initialization’ if needed.

Developer impact

Backup driver developers should implement new APIs.

Implementation

Assignee(s)

Primary assignee:
Ivan Kolodyazhny <e0ne@e0ne.info>
Other contributors:
Backup drivers maintainers.

Work Items

  • Implement ‘do_setup’ method in a base backup driver wich won’t do anything
  • Implement ‘do_setup’ in each backup driver.
  • Call driver’s ‘do_setup’ during backup-manager ‘init_host’ call.

Dependencies

None

Testing

Both unit and Tempest tests should be implemented to cover new feature.

Documentation Impact

None