How to create a backup

vmk8s

This guide contains recommended steps and useful commands for creating and managing backups to ensure smooth restores.

Prerequisites

Save current cluster credentials

For security reasons, charm credentials are not stored inside backups. So, if you plan to restore to a backup at any point in the future, you will need the following user passwords for your existing cluster:

  • operator

  • replication

  • rewind

You can retrieve them with:

juju run postgresql/leader get-password username=operator
juju run postgresql/leader get-password username=replication
juju run postgresql/leader get-password username=rewind

juju run postgresql-k8s/leader get-password username=operator
juju run postgresql-k8s/leader get-password username=replication
juju run postgresql-k8s/leader get-password username=rewind
Juju 2.9 users

Remember that juju run <action name> becomes juju run-action <action name> --wait for Juju 2.9.

See also: How to manage passwords and How to migrate a cluster.

Create a backup

Once you have a three-node cluster with configurations set for S3 storage, check that Charmed PostgreSQL is active and idle with juju status.

Once Charmed PostgreSQL is active and idle, you can create your first backup with the create-backup command:

juju run postgresql/leader create-backup

juju run postgresql-k8s/leader create-backup

By default, backups created with the command above will be full backups: a copy of all your data will be stored in S3. There are 2 other supported types of backups (available in revision 416+):

  • Differential: Only modified files since the last full backup will be stored.

  • Incremental: Only modified files since the last successful backup (of any type) will be stored.

To specify the desired backup type, use the type configuration parameter:

juju run postgresql/leader create-backup type={full|differential|incremental}

juju run postgresql-k8s/leader create-backup type={full|differential|incremental}

To avoid unnecessary service downtime, always use non-primary units for the action create-backup. Keep in mind that:

  • When TLS is enabled, create-backup can only run on replicas (non-primary)

  • When TLS is not enabled, create-backup can only run in the primary unit

List backups

You can list your available, failed, and in progress backups by running the list-backups command:

juju run postgresql/leader list-backups

juju run postgresql-k8s/leader list-backups