How to migrate cluster using backups

This is a How-To for restoring a backup that was made from the a different cluster, (i.e. cluster migration via restore). To perform a basic restore please reference the Restore How-To

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

• Have a single unit Charmed PostgreSQL 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

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-action postgresql-k8s/leader set-password username=operator password=<previous cluster password> --wait
juju run-action postgresql-k8s/leader set-password username=replication password=<previous cluster password> --wait
juju run-action postgresql-k8s/leader set-password username=rewind password=<previous cluster password> --wait

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

juju run-action postgresql-k8s/leader list-backups --wait

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

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-action postgresql-k8s/leader restore backup-id=YYYY-MM-DDTHH:MM:SSZ --wait

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