How to migrate a cluster

This guide describes how to restore a backup that was made from a different cluster, (i.e. cluster migration via restore).

See also

To perform a basic restore from a local backup, see How to restore a local backup.

Prerequisites

  • A MySQL deployment scaled down to one unit (scale it up after the backup is restored)

  • A backup from the previous cluster in your S3 storage

  • Passwords from your previous cluster

Set cluster passwords

When you restore a backup from an old cluster, it will restore the password from the previous cluster to your current cluster.

Set the password of your current cluster to the previous cluster’s password:

juju run mysql/leader set-password username=root password=<previous cluster password>
juju run mysql/leader set-password username=clusteradmin password=<previous cluster password>
juju run mysql/leader set-password username=serverconfig password=<previous cluster password>
juju run mysql/leader set-password username=backups password=<previous cluster password>
juju run mysql/leader set-password username=monitoring password=<previous cluster password>

juju run mysql-k8s/leader set-password username=root password=<previous cluster password>
juju run mysql-k8s/leader set-password username=clusteradmin password=<previous cluster password>
juju run mysql-k8s/leader set-password username=serverconfig password=<previous cluster password>
juju run mysql-k8s/leader set-password username=backups password=<previous cluster password>
juju run mysql-k8s/leader set-password username=monitoring password=<previous cluster password>

Juju 2.9 users

Remember that juju run <action name> becomes juju run-action <action name> --wait.

See also: Breaking changes between Juju 2.9 and 3

Restore cluster

To view the available backups to restore you can enter the command list-backups:

juju run mysql/leader list-backups

juju run mysql-k8s/leader list-backups

Take note of the backup-id that corresponds to the previous cluster.

Run the restore command with your backup-id:

juju run mysql/leader restore backup-id=YYYY-MM-DDTHH:MM:SSZ

juju run mysql-k8s/leader restore backup-id=YYYY-MM-DDTHH:MM:SSZ

Your restore will then be in progress, once it is complete your cluster will represent the state of the previous cluster.