A snapshot is the state of a Kubernetes volume at any given moment in time.

Snapshot Management via UI

To create a snapshot of an existing cluster, follow these steps:

1. In the top navigation bar of the Longhorn UI, click Volume.
2. Click the name of the volume for which you want to create a snapshot. This leads to the volume detail page.
3. Click the Take Snapshot button.

Once the snapshot is created, you will see it in the list of snapshots for the volume before the Volume Head.

Understanding the Snapshot Chain Visualization

On the Volume Details page, the Snapshots and Backups section displays the snapshot history as a chain. By default, the Show System Snapshots option is enabled, meaning all system-created snapshots are displayed automatically.

Each snapshot in the chain is color-coded to indicate its type or status, following a specific priority (highest status is displayed if multiple apply).

Snapshot Management with Custom Resources (CRs)

This section demonstrates how to create, list, restore, and delete Longhorn snapshots directly via kubectl using Longhorn’s Custom Resources (CRs).

Note: Longhorn uses its own Snapshot CRD under the longhorn.io API group (for example, v1beta2), not the generic Kubernetes VolumeSnapshot from snapshot.storage.k8s.io.

Create a Snapshot

1. Prepare the manifest: Create a file named longhorn-snapshot.yaml:

   apiVersion: longhorn.io/v1beta2
   kind: Snapshot
   metadata:
     name: longhorn-test-snapshot
     namespace: longhorn-system
   spec:
     volume: pvc-840804d8-6f11-49fd-afae-54bc5be639de   # replace with your actual Longhorn volume name
     createSnapshot: true
   

2. Apply the manifest:

   kubectl apply -f longhorn-snapshot.yaml
   

   Expected output:

   snapshot.longhorn.io/longhorn-test-snapshot created
   

   Note: If the volume is detached, you will see a brief warning about the engine not running. Longhorn automatically retries, and the snapshot will complete once the volume is attached.

List Snapshots

kubectl get snapshots.longhorn.io -l longhornvolume=pvc-840804d8-6f11-49fd-afae-54bc5be639de -n longhorn-system

Delete a Snapshot

kubectl delete snapshot.longhorn.io longhorn-test-snapshot -n longhorn-system

Expected output:

snapshot.longhorn.io "longhorn-test-snapshot" deleted

Note: Longhorn automatically handles the cleanup of the underlying data.

Data Engine Behavioral Differences

When deleting a snapshot that is the direct parent of the Volume Head (the current active state), the behavior of the Snapshot Custom Resource (CR) depends on the Data Engine being used:

This behavioral difference is expected. In v2 volumes, the immediate disappearance of the Snapshot CR indicates that the engine has successfully finalized the deletion and merged the data.