Stand-alone Volume Backup Overview

This guide will give you an overview of how stand-alone volume backup and restore process works in KubeStash.

How Backup Works

The following diagram shows how KubeStash takes backup of a stand-alone volume. Open the image in a new tab to see the enlarged version.

  

The backup process consists of the following steps:

1. At first, a user creates a Secret. This secret holds the credentials to access the backend where the backed up data will be stored.

2. Then, she creates a BackupStorage custom resource that specifies the backend information, along with the Secret containing the credentials needed to access the backend.

3. KubeStash operator watches for BackupStorage custom resources. When it finds a BackupStorage object, it initializes the BackupStorage by uploading the metadata.yaml file to the target storage.

4. Then, she creates a BackupConfiguration custom resource, targeting either a standalone PVC. The BackupConfiguration object specifies the Repository pointing to a BackupStorage that contains backend information, indicating where to upload backup data. It also defines the Addon information with a specified task and their configuration parameters to be used for backing up the volumes.

5. KubeStash operator watches for BackupConfiguration custom resources.

6. Once the KubeStash operator finds a BackupConfiguration object, it creates Repository with the information specified in the BackupConfiguration.

7. KubeStash operator watches for Repository custom resources. When it finds the Repository object, it Initializes Repository by uploading repository.yaml file to the spec.sessions[*].repositories[*].directory path specified in the BackupConfiguration.

8. Then, it creates a CronJob for each session with the schedule specified in BackupConfiguration to trigger backup periodically.

9. On the next scheduled slot, the CronJob triggers a backup by creating a BackupSession custom resource.

10. KubeStash operator watches for BackupSession custom resources.

11. When it finds a BackupSession object, it creates a Snapshot custom resource for each Repository specified in the respective session of the BackupConfiguration.

12. Then, it resolves the respective Addon and Function and prepares a backup Job definition.

13. Then, it mounts the targeted stand-alone volume into the Job and creates it.

14. The Job takes backup of the targeted stand-alone volume.

15. After the backup process is completed, the backup Job updates the status.components[*] field of the Snapshot object with target volume information.

How Restore Works

The following diagram shows how KubeStash restores backed up data into a stand-alone volume. Open the image in a new tab to see the enlarged version.

  

The restore process consists of the following steps:

1. At first, a user creates a stand-alone volume where the data will be restored or the user can use the same stand-alone volume.

2. Then, she creates a RestoreSession custom resource, specifies the target stand-alone volume where the backed-up data will be restored, the Repository object that points to a BackupStorage that holds backend information, and the target Snapshot, which will be restored. It also specifies the Addon info with task to use to restore the volume.

3. KubeStash operator watches for RestoreSession custom resources.

4. Once it finds a RestoreSession object, it resolves the respective Addon and Function and prepares a restore Job definition.

5. Then, it mounts the targeted volume and creates a Restore Job.

6. The restore Job restores the backed-up data into the targeted volume.

7. Finally, when the restore process is completed, the job updates the status.phase field of the Restoresession to reflect restore completion.

Next Steps

• Learn how to take backup and restore a stand-alone PVC from here.