Periodic OpenStack database backups

MOSK enables you to configure the periodic backup of the OpenStack database through the OpenStackDeployment object. To enable the backup, use the following structure:

spec:
  features:
    database:
      backup:
        enabled: true

MOSK uses the Mariabackup utility to back up the MariaDB Galera cluster data where the OpenStack data is stored. The Mariabackup gets launched on a periodic basis as a part of the Kubernetes cron job included in any MOSK deployment and is suspended by default.

By default, the backup job has the following configuration:

  • Runs on a daily basis at 01:00 AM

  • Creates incremental backups daily and full backups weekly

  • Keeps 10 latest full backups

  • Saves backups to the mariadb-phy-backup-data PVC

  • The backup timeout is 3600 seconds

  • The backup type is incremental

To override the default configuration, set the parameters and environment variables that are passed to the cron as described in the tables below.

MariaDB backup: Configuration parameters

Parameter

Type

Default

Description

--backup-type

String

incremental

Type of a backup. The list of possible values include:

  • incremental

    If the newest full backup is older than the value of the full_backup_cycle parameter, the system performs a full backup. Otherwise, the system performs an incremental backup of the newest full backup.

  • full

    Always performs only a full backup.

Usage example:

spec:
  features:
    database:
      backup:
        backup_type: incremental

--backup-timeout

Integer

21600

Timeout in seconds for the system to wait for the backup operation to succeed.

Usage example:

spec:
  services:
    database:
      mariadb:
        values:
          conf:
            phy_backup:
              backup_timeout: 30000

--allow-unsafe-backup

Boolean

false

Not recommended, removed since MOSK 22.4.

If set to true, enables the MariaDB cluster backup in a not fully operational cluster, where:

  • The current number of ready pods is not equal to MARIADB_REPLICAS.

  • Some replicas do not have healthy wsrep statuses.

Usage example:

spec:
  services:
    database:
      mariadb:
        values:
          conf:
            phy_backup:
              allow_unsafe_backup: true
MariaDB backup: Environment variables

Variable

Type

Default

Description

MARIADB_BACKUPS_TO_KEEP

Integer

10

Number of full backups to keep.

Usage example:

spec:
  features:
    database:
      backup:
        backups_to_keep: 3

MARIADB_BACKUP_PVC_NAME

String

mariadb-phy-backup-data

Persistent volume claim used to store backups.

Usage example:

spec:
  services:
    database:
      mariadb:
        values:
          conf:
            phy_backup:
              backup_pvc_name: mariadb-phy-backup-data

MARIADB_FULL_BACKUP_CYCLE

Integer

604800

Number of seconds that defines a period between 2 full backups. During this period, incremental backups are performed. The parameter is taken into account only if backup_type is set to incremental. Otherwise, it is ignored. For example, with full_backup_cycle set to 604800 seconds a full backup is taken weekly and, if cron is set to 0 0 * * *, an incremental backup is performed on daily basis.

Usage example:

spec:
  features:
    database:
      backup:
        full_backup_cycle: 70000

MARIADB_BACKUP_REQUIRED_SPACE_RATIO

Floating

1.2

Multiplier for the database size to predict the space required to create a backup, either full or incremental, and perform a restoration keeping the uncompressed backup files on the same file system as the compressed ones.

To estimate the size of MARIADB_BACKUP_REQUIRED_SPACE_RATIO, use the following formula: size of (1 uncompressed full backup + all related incremental uncompressed backups + 1 full compressed backup) in KB =< (DB_SIZE * MARIADB_BACKUP_REQUIRED_SPACE_RATIO) in KB.

The DB_SIZE is the disk space allocated in the MySQL data directory, which is /var/lib/mysql, for databases data excluding galera.cache and ib_logfile* files. This parameter prevents the backup PVC from being full in the middle of the restoration and backup procedures. If the current available space is lower than DB_SIZE * MARIADB_BACKUP_REQUIRED_SPACE_RATIO, the backup script fails before the system starts the actual backup and the overall status of the backup job is failed.

Usage example:

spec:
  services:
    database:
      mariadb:
        values:
          conf:
            phy_backup:
              backup_required_space_ratio: 1.4

For example, to perform full backups monthly and incremental backups daily at 02:30 AM and keep the backups for the last six months, configure the database backup in your OpenStackDeployment object as follows:

spec:
  features:
    database:
      backup:
        enabled: true
        backups_to_keep: 6
        schedule_time: '30 2 * * *'
        full_backup_cycle: 2628000

See also

Operarions Guide: Enable a periodic backup