The way K3s is backed up and restored depends on which type of datastore is used.

Backup and Restore with External Datastore

When an external datastore is used, backup and restore operations are handled outside of K3s. The database administrator will need to back up the external database, or restore it from a snapshot or dump.

We recommend configuring the database to take recurring snapshots.

For details on taking database snapshots and restoring your database from them, refer to the official database documentation:

Backup and Restore with Embedded etcd Datastore (Experimental)

Available as of v1.19.1+k3s1

In this section, you’ll learn how to create backups of the K3s cluster data and to restore the cluster from backup.

Creating Snapshots

Snapshots are enabled by default.

The snapshot directory defaults to /server/db/snapshots.

To configure the snapshot interval or the number of retained snapshots, refer to the options.

Restoring a Cluster from a Snapshot

When K3s is restored from backup, the old data directory will be moved to /server/db/etcd-old/. Then K3s will attempt to restore the snapshot by creating a new data directory, then starting etcd with a new K3s cluster with one etcd member.

To restore the cluster from backup, run K3s with the --cluster-reset option, with the --cluster-reset-restore-path also given:

./k3s server \
  --cluster-reset \
  --cluster-reset-restore-path=<PATH-TO-SNAPSHOT>

Result: A message in the logs says that K3s can be restarted without the flags. Start k3s again and should run successfully and be restored from the specified snapshot.

Options

These options can be passed in with the command line, or in the configuration file, which may be easier to use.

Options Description
--etcd-disable-snapshots Disable automatic etcd snapshots
--etcd-snapshot-schedule-cron value Snapshot interval time in cron spec. eg. every 5 hours * */5 * * *(default: 0 */12 * * *)
--etcd-snapshot-retention value Number of snapshots to retain (default: 5)
--etcd-snapshot-dir value Directory to save db snapshots. (Default location: ${data-dir}/db/snapshots)
--cluster-reset Forget all peers and become sole member of a new cluster. This can also be set with the environment variable [$K3S_CLUSTER_RESET].
--cluster-reset-restore-path value Path to snapshot file to be restored