Note: All commands are written for juju >= v.3.0
If you are using an earlier version, check the Juju 3.0 Release Notes.
How to restore a local backup
This is a guide on how to restore a locally made backup.
To restore a backup that was made from a different cluster, (i.e. cluster migration via restore), see How to migrate cluster using backups.
Prerequisites
- Deployments have been scaled-down to a single PostgreSQL unit (scale it up after the backup is restored)
- Access to S3 storage
- Configured settings for S3 storage
- Existing backups in your S3-storage
- Point-in-time recovery requires the following PostgreSQL charm revisions:
- 435+ for
arm64
- 436+ for
amd64
- 435+ for
Summary
List backups
To view the available backups to restore, use the command list-backups
:
juju run postgresql-k8s/leader list-backups
This should show your available backups like in the sample output below:
list-backups: |-
Storage bucket name: canonical-postgres
Backups base path: /test/backup/
backup-id | action | ... | timeline
---------------------------------------------------------------------------
2024-07-22T13:11:56Z | full backup | ... | 1
2024-07-22T14:12:45Z | incremental backup | ... | 1
2024-07-22T15:34:24Z | restore | ... | 2
2024-07-22T16:26:48Z | incremental backup | ... | 2
2024-07-22T17:17:59Z | full | ... | 2
2024-07-22T18:05:32Z | restore | ... | 3
Below is a complete list of parameters shown for each backup/restore operation:
backup-id
: unique identifier of the backup.action
: indicates the action performed by the user through one of the charm action; can be any of full backup, incremental backup, differential backup or restore.status
: either finished (successfully) or failed.reference-backup-id
LSN start/stop
: a database specific number (or timestamp) to identify its state.start-time
: records start of the backup operation.finish-time
: records end of the backup operation.backup-path
: path of the backup related files in the S3 repository.timeline
: number which identifies different branches in the database transactions history; every time a restore or PITR is made, this number is incremented by 1.
Point-in-time recovery
Point-in-time recovery (PITR) is a PostgreSQL feature that enables restorations to the database state at specific points in time.
After performing a PITR in a PostgreSQL cluster, a new timeline is created to track from the point to where the database was restored. They can be tracked via the timeline
parameter in the list-backups
output.
Restore backup
To restore a backup from that list, run the restore
command and pass the parameter corresponding to the backup type.
When the user needs to restore a specific backup that was made, they can use the backup-id
that is listed in the list-backups
output.
juju run postgresql-k8s/leader restore backup-id=YYYY-MM-DDTHH:MM:SSZ
However, if the user needs to restore to a specific point in time between different backups (e.g. to restore only specific transactions made between those backups), they can use the restore-to-time
parameter to pass a timestamp related to the moment they want to restore.
juju run postgresql-k8s/leader restore restore-to-time="YYYY-MM-DDTHH:MM:SSZ"
Your restore will then be in progress.
It’s also possible to restore to the latest point from a specific timeline by passing the ID of a backup taken on that timeline and restore-to-time=latest
when requesting a restore.