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backup-restore.md

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Backup and restore

Kubernetes uses Etcd as the key-value store for its resource definitions. Gardener supports the backup and restore of etcd. It is the responsibility of the shoot owners to backup the workload data.

Gardener uses etcd-backup-restore component to backup the etcd backing the Shoot cluster regularly and restore in case of disaster. It is deployed as sidecar via etcd-druid. This doc mainly focuses on the backup and restore configuration used by Gardener when deploying these components. For more details on the design and internal implementation details, please refer GEP-06 and documentation on individual repository.

Bucket provisioning

Refer the backup bucket extension document to know details about configuring backup bucket.

Backup Policy

etcd-backup-restore supports full snapshot and delta snapshots over full snapshot. In Gardener, this configuration is currently hard-coded to following parameters:

  • Full Snapshot Schedule:
    • Daily, 24hr interval.
    • For each Shoot, the schedule time in a day is randomized based on the configured Shoot maintenance window.
  • Delta Snapshot schedule:
    • At 5min interval.
    • If aggregated events size since last snapshot goes beyond 100Mib.
  • Backup History / Garbage backup deletion policy:
    • Gardener configure backup restore to have Exponential garbage collection policy.
    • As per policy, following backups are retained.
    • All full backups and delta backups for the previous hour.
    • Latest full snapshot of each previous hour for the day.
    • Latest full snapshot of each previous day for 7 days.
    • Latest full snapshot of the previous 4 weeks.
    • Garbage Collection is configured at 12hr interval.
  • Listing:
    • Gardener don't have any API to list out the backups.
    • To find the backup list, admin can checkout the BackupEntry resource associated with Shoot which holds the bucket and prefix details on object store.

Restoration

Restoration process of etcd is automated through the etcd-backup-restore component from latest snapshot. Gardener dosen't support Point-In-Time-Recovery (PITR) of etcd. In case of etcd disaster, the etcd is recovered from latest backup automatically. For further details, please refer the doc. Post restoration of etcd, the Shoot reconciliation loop brings back the cluster to same state.

Again, Shoot owner is responsible for maintaining the backup/restore of his workload. Gardener does only take care of the cluster's etcd.