How to migrate a cluster

This is a How-To for how to restore a backup that was made from a different cluster, (i.e. cluster migration via restore).

To perform a basic restore from a local backup, please reference the Restore How-To.

Prerequisites

Restoring a backup from a previous cluster to a current cluster requires that you:

• Have a single unit Charmed MySQL deployed and running
• Access to S3 storage
• Have configured settings for S3 storage
• Have the backups from the previous cluster in your S3-storage
• Have the passwords from your previous cluster

Manage 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>

List backups

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

juju run mysql/leader list-backups

This shows a list of the available backups (it is up to you to identify which backup-id corresponds to the previous-cluster):

    backups: |-
      backup-id             | backup-type  | backup-status
      ----------------------------------------------------
      YYYY-MM-DDTHH:MM:SSZ  | physical     | finished

Restore backup

To restore your current cluster to the state of the previous cluster, run the restore command and pass the correct backup-id to the command:

juju run mysql/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.