Overview of the OpenStack database backup and restoration

MOSK relies on the MariaDB Galera cluster to provide its OpenStack components with a reliable storage for persistent data. Mirantis recommends backing up your OpenStack databases daily to ensure the safety of your cloud data. Also, you should always create an instant backup before updating your cloud or performing any kind of potentially disruptive experiment.

MOSK has a built-in automated backup routine that can be triggered manually or by schedule. For detailed information about the process of MariaDB Galera cluster backup, refer to Workflows of the OpenStack database backup and restoration.

Backup and restoration can only be performed against the OpenStack database as a whole. Granular per-service or per-table procedures are not supported by MOSK.

Periodic backups

By default, periodic backups are turned off. Though, a cloud operator can easily enable this capability by adding the following structure to the OpenStackDeployment custom resource:

        enabled: true

For the configuration details, refer to Periodic OpenStack database backups.

Database restoration

Along with the automated backup routine, MOSK provides the Mariabackup tool for the OpenStack database restoration. For the database restoration procedure, refer to Restore OpenStack databases from a backup. For more information about the restoration process, consult Workflows of the OpenStack database backup and restoration.

Storage for backup data

By default, MOSK backup routine stores the OpenStack database data into the Mirantis Ceph cluster, which is a part of the same cloud. This is sufficient for the vast majority of clouds. However, you may want to have the backup data stored off the cloud to comply with specific enterprise practices for infrastructure recovery and data safety.

To achieve that, MOSK enables you to point the backup routine to an external data volume. For details, refer to Remote storage for OpenStack database backups.

Size of a backup storage

The size of a backup storage volume depends directly on the size of the MOSK cluster, which can be determined through the size parameter in the OpenStackDeployment CR.

The list of the recommended sizes for a minimal backup volume includes:

  • 20 GB for the tiny cluster size

  • 40 GB for the small cluster size

  • 80 GB for the medium cluster size

If required, you can change the default size of a database backup volume. However, make sure that you configure the volume size before OpenStack deployment is complete. This is because there is no automatic way to resize the backup volume once the cloud is deployed. Also, only the local backup storage (Ceph) supports the configuration of the volume size.

To change the default size of the backup volume, use the following structure in the OpenStackDeployment CR:

              size: "200Gi"

Local backup storage - default

To store the backup data to a local Mirantis Ceph, the MOSK underlying Kubernetes cluster needs to have a preconfigured storage class for Kubernetes persistent volumes with the Ceph cluster as a storage backend.

When restoring the OpenStack database from a local Ceph storage, the cron job restores the state on each MariaDB node sequentially. It is not possible to perform parallel restoration because Ceph Kubernetes volumes do not support concurrent mounting from multiple places.

Remote backup storage

MOSK provides you with a capability to store the OpenStack database data outside of the cloud, on an external storage device that supports common data access protocols, such as third-party NAS appliances.

Refer to Remote storage for OpenStack database backups for the configuration details.