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Longhorn provides a lightweight, reliable, and distributed block storage solution for Kubernetes, offering seamless backups of your persistent volumes (PVs) and ensuring your data is protected from failure.

In this post, we’ll dive into how Longhorn backups work, best practices for using them, and how to automate your backup process to protect your critical data.

Why Longhorn for Backups?

Longhorn is designed specifically for stateful workloads in Kubernetes. With native support for snapshots and backups, it ensures that data stored in Persistent Volume Claims (PVCs) is protected.

Key benefits include:

  • Snapshots and backups to S3-compatible storage.
  • Disaster recovery: Quickly restore volumes after failures.
  • Backup automation: Schedule backups for critical applications.
  • Easy management via UI or CLI.

Setting Up Longhorn

1. Install Longhorn with Helm

helm repo add longhorn https://charts.longhorn.io
helm repo update
helm install longhorn longhorn/longhorn --namespace longhorn-system

Once installed, access the Longhorn UI through your Kubernetes service, or use the kubectl proxy to connect locally.

Taking Snapshots and Backups

1. Creating a Snapshot

Snapshots are local, point-in-time copies of your volumes. These snapshots are quick to create and can be used for local restores.

kubectl annotate pvc my-pvc -n my-namespace backup=true

Alternatively, use the Longhorn UI to take snapshots manually by selecting the volume and clicking Create Snapshot.

2. Creating Backups to S3

Backups store snapshots to an external S3-compatible storage, protecting your data from node failures or cluster outages.

Configure Longhorn Backup Target:

In the Longhorn UI, navigate to Settings → Backup Target and configure it:

s3://my-longhorn-backup-bucket@us-east-1/

You can also configure this target during installation:

helm install longhorn longhorn/longhorn --namespace longhorn-system \
  --set backupTarget="s3://my-bucket@us-east-1" \
  --set backupAccessKey="S3_ACCESS_KEY" \
  --set backupSecretKey="S3_SECRET_KEY"

Trigger a Backup:

Back up a volume snapshot to S3 using the Longhorn UI or via kubectl:

kubectl annotate pvc my-pvc -n my-namespace backup=true

Longhorn will upload the snapshot to your configured S3-compatible storage.

Restoring Backups

To restore a backup from S3 storage, select the Restore option in the Longhorn UI, or create a new PVC linked to the backup:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: restored-pvc
spec:
  storageClassName: longhorn
  dataSource:
    name: <backup-name>
    kind: VolumeSnapshot
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi

This will restore the backup to a new volume, ready to be mounted and used.

Automating Backups

Use CronJobs to automate backups for your PVCs. For example:

kubectl create cronjob pvc-backup \
  --schedule="0 * * * *" \
  --image=busybox \
  -- /bin/sh -c "kubectl annotate pvc my-pvc -n my-namespace backup=true"

Alternatively, you can configure automated backups directly in the Longhorn UI by setting a recurring backup policy.

Monitoring Backup Health

Integrate Prometheus with Longhorn to monitor backup success and alert you to any failures. You can set up AlertManager notifications to ensure you’re notified when a backup fails or hasn’t run as expected.

Best Practices for Longhorn Backups

  1. Automate Backups: Use recurring backup policies in Longhorn to avoid manual processes.
  2. Test Restores Regularly: A backup is only useful if it can be restored—regularly verify your restore process.
  3. Offsite Backup Storage: Store backups in S3 or other cloud storage to protect against local failures.
  4. Monitor Backup Health: Use Prometheus and AlertManager to stay on top of backup performance.
  5. Secure Backup Data: Use encryption for sensitive data to ensure backups are secure.

Conclusion

Longhorn makes it easy to back up and restore persistent data in Kubernetes, giving you peace of mind that your critical workloads are protected. With snapshots, S3 backups, and easy restore options, Longhorn ensures your PVCs are safe even in the event of cluster or node failures.

To learn more about other backup tools and strategies, check out:

With Longhorn, you can confidently automate your backups, test your restores, and keep your data protected.