openstack/cinder-specs
Code Issues Proposed changes
2d21f45ebd
cinder-specs/specs/victoria/backup-backends-configuration.rst
Ivan Kolodyazhny 8ffad2aec7 Backup Backends Configuration 
Change-Id: Ifa4c6c0ab8ef79d889a092f3caaf7304316cb3d5
Related: blueprint backup-backends-configuration
2020-07-01 12:56:22 +03:00

5.5 KiB
Raw Blame History

Backup Multi-Backends Configuration

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

Add a new config section for backup configuration options to unify the way how we do it with volume drivers and support multiple backup drivers in one service.

Problem description

Right now we've got all backup-specific configuration options defined in the [DEFAULT] section:

[DEFAULT]
backup_driver = cinder.backup.drivers.ceph.CephBackupDriver
backup_ceph_user = cinder-backups
backup_ceph_pool = volume-backups
...

It leads to mix of backup-specific config options and Cinder general configuration. This approach also doesn't support backups multi-backend. Operators can configure multiple backup backends only by configuring several cinder-backup services.

Current approach blocks Generic backup implementation because drivers self.configuration won't be able to see required configuration which are defined in the [DEFAULT] section.

Use Cases

The main use-case here is to decouple backup-specific configuration from the [DEFAULT] section and introduce a backup_type.

Proposed change

The new config option called 'enabled_backup_backends' will contain a list of enabled backup backends. This will implement the same approach as we have for volumes with 'enabled_backends' config option.

All backup-related configuration will be moved into the new backend-specific section:

[DEFAULT]
enabled_backup_backends = ceph_backup, ceph_backup_ssd
default_backup_type = ceph-backup-type
...

[ceph_backup]
backup_driver = cinder.backup.drivers.ceph.CephBackupDriver
backup_ceph_user = cinder-backups
backup_ceph_pool = volume-backups

[ceph_backup_ssd]
backup_driver = cinder.backup.drivers.ceph.CephBackupDriver
backup_ceph_user = cinder-backups
backup_ceph_pool = volume-backups-ssd

The old-style backup configuration will be supported at least for one release to follow all deprecation policies.

With multi-backups configuration we want to introduce backup types too. It will help us to use all multi-backend advantages. Backup types will follow the same approach as volume types have:

  • __DEFAULT__ backup type will be introduced and all existing backups will be migrated to this backup type.
  • default_backup_type config option will be introduced.
  • Backup types will have own extra specs.

Alternatives

Leave everything as-is and introduce some hacks in the code to get volume drivers working as a backup drivers in the scope of Generic Backup feature.

Data model impact

New tables for backup types will be introduced. We'll follow the same approach as for volume types which works well for Cinder:

BackupType +--------------+--------------+ | Field | Type | +--------------+--------------+ | created_at | datetime | | updated_at | datetime | | id | varchar(36) | | name | varchar(255) | | description | varchar(255) | | deleted | boolean | | is_public | boolean | +--------------+--------------+

BackupTypeProjects +----------------+--------------+ | Field | Type | +----------------+--------------+ | created_at | datetime | | updated_at | datetime | | id | varchar(36) | | project_id | varchar(36) | | backup_type_id | varchar(36) | | deleted | boolean | +----------------+--------------+

BackupTypeExtraSpecs +----------------+--------------+ | Field | Type | +----------------+--------------+ | created_at | datetime | | updated_at | datetime | | key | varchar(255) | | value | varchar(255) | | deleted | boolean | +----------------+--------------+

REST API impact

New API endpoints will be implemented for backup types. It should be similar like volume type API.

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

Backup creation procedure will contain few more database calls but it should not affect performance a lot.

Other deployer impact

Operators should configure backups using a new mechanism and migrate from old-style configuration.

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

e0ne

Work Items

  • Add a new 'enabled_backup_backends' config option and deprecate old-style config
  • Modify the backup manager to honor new configuration
  • Add some unit tests
  • Devstack should be able to configure cinder backups in a new way
  • Operator documentation should be updated
  • API reference should be updated

Dependencies

None

Testing

  • Unit tests
  • Existing tempest tests will cover new functionality

Documentation Impact

  • Update documentation to describe new config option
  • New REST API endpoints will be documented

References