blueprint database-backup-recovery
Introduce a new option, mariadb_backup, which takes a backup of all
databases hosted in MariaDB.
Backups are performed using XtraBackup, the output of which is saved to
a dedicated Docker volume on the target host (which defaults to the
first node in the MariaDB cluster).
It supports either full (the default) or incremental backups.
Change-Id: Ied224c0d19b8734aa72092aaddd530155999dbc3