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Stash v2023.03.20
supports backup and restore operation of many databases. This guide will give you an overview of how Etcd database backup and restore process works in Stash.
Stash supports taking backup of Etcd database using etcdctl. It is the most flexible way to perform backup and restore of Etcd database.
The following diagram shows how Stash takes backup of a Etcd database. Open the image in a new tab to see the enlarged version.
The backup process consists of the following steps:
At first, a user creates a secret with access credentials of the backend where the backed up data will be stored.
Then, she creates a Repository
crd that specifies the backend information along with the secret that holds the credentials to access the backend.
Then, she creates a BackupConfiguration
crd targeting the AppBinding crd of the desired database. The BackupConfiguration
object also specifies the Task
to use to backup the database.
Stash operator watches for BackupConfiguration
crd.
Once Stash operator finds a BackupConfiguration
crd, it creates a CronJob with the schedule specified in BackupConfiguration
object to trigger backup periodically.
On the next scheduled slot, the CronJob triggers a backup by creating a BackupSession
crd.
Stash operator also watches for BackupSession
crd.
When it finds a BackupSession
object, it resolves the respective Task
and Function
and prepares a Job definition to backup.
Then, it creates the Job to backup the targeted database.
The backup Job reads the necessary information to connect with the database from the AppBinding
crd. It also reads backend information and access credentials from Repository
crd and Storage Secret respectively.
Then, the Job takes snapshot of the targeted database using etcdctl
and uploads the snapshot to the backend. Stash stores the snapshot temporarily in a directory before uploading that into the backend. You can limit the temporary directory size using spec.TempDir
field of BackupConfiguration
crd.
Finally, when the backup is complete, the Job sends Prometheus metrics to the Pushgateway running inside Stash operator pod. It also updates the BackupSession
and Repository
status to reflect the backup completion.
The following diagram shows how Stash restores an Etcd database from a backup. Open the image in a new tab to see the enlarged version.
The restore process consists of the following steps:
At first, a user creates a RestoreSession
crd targeting the AppBinding
of the desired database where the backed up data will be restored. It also specifies the Repository
crd which holds the backend information and the Task
to use to restore the target.
Stash operator watches for RestoreSession
object.
Once it finds a RestoreSession
object, it resolves the respective Task
and Function
and prepares a Job definition to restore.
Then, it creates the Job to restore the target.
The Job reads necessary information to connect with the database from respective AppBinding
crd. It also reads backend information and access credentials from Repository
crd and Storage Secret respectively.
Then, the job downloads the backed up snapshot from the backend and restore that snapshot into the Etcd
database. Stash stores the downloaded files temporarily before inserting into the targeted database.
Finally, when the restore process is complete, the Job sends Prometheus metrics to the Pushgateway and update the RestoreSession
status to reflect restore completion.