Backup and Restore OpenStack Service Databases

Kolla Ansible provides a utility to create copies of all OpenStack service databases, called mariadb_backup. In this section, we explain how to use Kolla Ansible's builtin function to create database backups of a Private Cloud's OpenStack services.

Prerequisites

Before proceeding with this guide, a Kolla Ansible environment needs to be prepared. For information about preparing a Kolla Ansible environment, see How to Prepare and Use Kolla Ansible. Once the environment is prepared, come back to this guide to learn how to create database backups of OpenStack services.

How to Create OpenStack Service Database Backups

The following instruction must be performed from the folder in which you have prepared Kolla Ansible. This section first provides the command syntax, then follows up with an example of the command's execution and output. Note that Kolla Ansible has no way to schedule backups.

Create a Full Database Backup with Kolla Ansible

From the host that has Kolla Ansible prepared, the following command is executed:

kolla-ansible \
    -i /opt/kolla-ansible-cli/inventory.yml \
    -i /opt/kolla-ansible-cli/ansible/inventory/multinode \
    mariadb_backup

Truncated output of the above command:

Backup MariaDB databases : ansible-playbook -e @/etc/kolla/globals.yml  -e @/etc/kolla/globals.d/custom-globals.yml -e @/etc/kolla/passwords.yml -e CONFIG_DIR=/etc/kolla  -e kolla_action=backup -e mariadb_backup_type=full /opt/kolla-ansible-cli/.venv/share/kolla-ansible/ansible/mariadb_backup.yml  --inventory inventory.yml --inventory ansible/inventory/multinode

PLAY [Backup MariaDB] ***********************************************************************************************************************************************************************

[...output truncated...]

TASK [mariadb : Taking full database backup via Mariabackup] ********************************************************************************************************************************
skipping: [encouraging-bobcat.local]
skipping: [hardcore-rodent.local]
changed: [comfortable-lark.local]

PLAY RECAP **********************************************************************************************************************************************************************************
comfortable-lark.local     : ok=5    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
encouraging-bobcat.local   : ok=3    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0
hardcore-rodent.local      : ok=3    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0

The task [mariadb : Taking full database backup via Mariabackup] is where a backup of all OpenStack service databases is created. Kolla Ansible creates a Docker volume called mariadb_backup to store the database copies. Previous backups made using this method are not overwritten. The host under this task that reports a change (example: changed=1) is where the Docker volume storing the databases is created.

Note: For this example, since the Docker volume was created on another host, the remaining instruction in this guide must be performed from that host. If Kolla Ansible creates mariadb_backup on another host, you must SSH into that host as root to continue this process.

Create an Incremental Database Backup with Kolla Ansible

Note: Incremental backups can only be made if a full backup has been made prior, otherwise the following command will result in an error.

From the host that has Kolla Ansible prepared, the following command is executed:

kolla-ansible \
    -i /opt/kolla-ansible-cli/inventory.yml \
    -i /opt/kolla-ansible-cli/ansible/inventory/multinode \
    mariadb_backup \
    --incremental

Truncated output of the above command:

Backup MariaDB databases : ansible-playbook -e @/etc/kolla/globals.yml  -e @/etc/kolla/globals.d/custom-globals.yml -e @/etc/kolla/passwords.yml -e CONFIG_DIR=/etc/kolla  -e kolla_action=backup -e mariadb_backup_type=incremental /opt/kolla-ansible-cli/.venv/share/kolla-ansible/ansible/mariadb_backup.yml  --inventory inventory.yml --inventory ansible/inventory/multinode
[WARNING]: Invalid characters were found in group names but not replaced, use -vvvv to see details

PLAY [Backup MariaDB] ***********************************************************************************************************************************************************************

[...output truncated...]

TASK [mariadb : Taking incremental database backup via Mariabackup] *************************************************************************************************************************
skipping: [encouraging-bobcat.local]
skipping: [hardcore-rodent.local]
changed: [comfortable-lark.local]

PLAY RECAP **********************************************************************************************************************************************************************************
comfortable-lark.local     : ok=5    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
encouraging-bobcat.local   : ok=3    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0
hardcore-rodent.local      : ok=3    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0

The task [mariadb : Taking incremental database backup via Mariabackup] is where an incremental backup of all OpenStack service databases is created. Kolla Ansible creates a Docker volume called mariadb_backup to store the database copies. Previous backups made using this method are not overwritten. The host under this task that reports a change (example: changed=1) is where the Docker volume storing the databases is created.

Note: For this example, since the Docker volume was created on another host, the remaining instruction in this guide must be performed from that host. If Kolla Ansible creates mariadb_backup on another host, you must SSH into that host as root to continue this process.

How to Restore a Private Cloud's OpenStack Service Databases

This section explains how to restore both full and incremental database backups created using Kolla Ansible's mariadb_backup function.

Full Database Backup Restoration

Follow these steps to restore a full MariaDB database backup of OpenStack service databases.

Note: Make sure you run these commands from the host that contains the mariadb_backup Docker volume. The mariadb_backup Kolla Ansible command ran earlier outputs the host where this volume was created. Run docker volume ls | grep mariadb_backup to check.

Full Database Restoration Steps

1. In this section, we create a temporary Docker container called *dbrestore. This container is created with the same volumes as the mariadb Docker container. The mariadb_backup Docker volume is mounted as /backup in this container. Finally, the container is created using the registry.flexmetal.net/kolla/mariadb-server:2023.2-ubuntu-jammy Docker image available from our registry.

Create the temporary Docker container called dbrestore using:

docker run \
    --rm -it \
    --volumes-from mariadb \
    --name dbrestore \
    --volume mariadb_backup:/backup \
    registry.flexmetal.net/kolla/mariadb-server:2023.2-ubuntu-jammy \
    /bin/bash

Once you run the above Docker command, your terminal should appear this way:

()[mysql@312d0cd3edbe /]$

2. Next, the backup data must be prepared before it can be copied into place. This example uses a full MariaDB backup called mysqlbackup-29-08-2025-1756478084.qp.xbc.xbs.gz.

To prepare the backup data, in the Docker container, run:

cd /backup/
rm -rf /backup/restore
mkdir -p /backup/restore/full
gunzip mysqlbackup-29-08-2025-1756478084.qp.xbc.xbs.gz
mbstream -x -C /backup/restore/full/ < mysqlbackup-29-08-2025-1756478084.qp.xbc.xbs
mariabackup --prepare --target-dir /backup/restore/full

3. With Kolla Ansible, stop the MariaDB service:

kolla-ansible \
    -i inventory.yml \
    -i ansible/inventory/multinode \
    stop \
    --tags mariadb \
    --yes-i-really-really-mean-it

4. Navigate back to the Docker container and run:

rm -rf /var/lib/mysql/*
rm -rf /var/lib/mysql/\.[^\.]*
mariabackup --copy-back --target-dir /backup/restore/full

5. Next, with Kolla Ansible run MariaDB recovery while specifying the host from which the database backup was restored:

kolla-ansible \
    -i /opt/kolla-ansible-cli/inventory.yml \
    -i /opt/kolla-ansible-cli/ansible/inventory/multinode \
    mariadb_recovery \
    -e mariadb_recover_inventory_name=comfortable-lark.local

Examine MariaDB's logs to confirm the Galera cluster has synchronized:

# less /var/log/kolla/mariadb/mariadb.log
2025-08-29 15:12:13 0 [Note] WSREP: Shifting JOINED -> SYNCED (TO: 132)
2025-08-29 15:12:13 2 [Note] WSREP: Server comfortable-lark synced with group
2025-08-29 15:12:13 2 [Note] WSREP: Server status change joined -> synced
2025-08-29 15:12:13 2 [Note] WSREP: Synchronized with group, ready for connections

Incremental Database Restoration

Follow these steps to learn how to restore an incremental OpenStack service database backup created using Kolla Ansible's mariadb_backup function.

Note: Make sure you run these commands from the host that contains the mariadb_backup Docker volume. The mariadb_backup Kolla Ansible command ran earlier outputs the host where this volume was created. Run docker volume ls | grep mariadb_backup to check.

Incremental Database Restoration Steps

1. In this section, we create a temporary Docker container called *dbrestore. This container is created with the same volumes as the mariadb Docker container. The mariadb_backup Docker volume is mounted as /backup in this container. Finally, the container is created using the registry.flexmetal.net/kolla/mariadb-server:2023.2-ubuntu-jammy Docker image available from Docker Hub with a Bash shell.

Create the temporary Docker container called dbrestore using:

docker run --rm -it \
    --volumes-from mariadb \
    --name dbrestore \
    --volume mariadb_backup:/backup \
    registry.flexmetal.net/kolla/mariadb-server:2023.2-ubuntu-jammy \
    /bin/bash

Once you run the above Docker command, your terminal should appear this way:

()[mysql@fe16a3c81311 /]$

2. Next, we must prepare the backup data before it can be copied into place.

Note: This section assumes a full and incremental backup have been created. The full and incremental backup file names will differ from this example.

In the Docker container, run:

cd /backup/
rm -rf /backup/restore
mkdir -p /backup/restore/full
mkdir -p /backup/restore/incremental
gunzip mysqlbackup-10-12-2021-1639166052.qp.xbc.xbs.gz
gunzip incremental-20-mysqlbackup-10-12-2021-1639169695.qp.xbc.xbs.gz
mbstream -x -C /backup/restore/full/ < mysqlbackup-10-12-2021-1639166052.qp.xbc.xbs
mbstream -x -C /backup/restore/incremental/ < incremental-20-mysqlbackup-10-12-2021-1639169695.qp.xbc.xbs
mariabackup --prepare --target-dir=/backup/restore/full/
mariabackup --prepare --target-dir=/backup/restore/full/ --incremental-dir=/backup/restore/incremental/

3. With Kolla Ansible, stop the MariaDB service:

kolla-ansible \
    -i /opt/kolla-ansible-cli/inventory.yml \
    -i /opt/kolla-ansible-cli/ansible/inventory/multinode \
    stop \
    --tags mariadb \
    --yes-i-really-really-mean-it

4. Navigate back to the dbrestore Docker container and run:

rm -rf /var/lib/mysql/*
rm -rf /var/lib/mysql/\.[^/.]*
mariabackup --copy-back --target-dir /backup/restore/full/

5. Next, with Kolla Ansible run MariaDB recovery while specifying the host from which the database backup was restored:

kolla-ansible \
    -i /opt/kolla-ansible-cli/inventory.yml \
    -i /opt/kolla-ansible-cli/ansible/inventory/multinode \
    mariadb_recovery \
    -e mariadb_recover_inventory_name=comfortable-lark.local

Examine MariaDB's logs to confirm the Galera cluster has synchronized:

# less /var/log/kolla/mariadb/mariadb.log
2025-08-29 16:55:41 0 [Note] WSREP: Shifting JOINED -> SYNCED (TO: 128)
2025-08-29 16:55:41 6 [Note] WSREP: Server comfortable-lark synced with group
2025-08-29 16:55:41 6 [Note] WSREP: Server status change joined -> synced
2025-08-29 16:55:41 6 [Note] WSREP: Synchronized with group, ready for connections

References

• Kolla Ansible's MariaDB database backup and restore
• MariaDB's Full Backup and Restore with Mariabackup
• MariaDB's Incremental Backup and Restore with Mariabackup