Enable CSI Snapshot Support on a Cluster

Enable CSI Snapshot Support for Programmatic Creation of Longhorn Snapshots/Backups

Prerequisite

It is the responsibility of the Kubernetes distribution to deploy the snapshot controller as well as the related custom resource definitions.

For more information, see CSI Volume Snapshots.

If your Kubernetes Distribution Does Not Bundle the Snapshot Controller

You may manually install these components by executing the following steps.

Prerequisite

Please install the same release version of snapshot CRDs and snapshot controller to ensure that the CRD version is compatible with the snapshot controller.

For general use, update the snapshot controller YAMLs with an appropriate namespace prior to installing.

For example, on a vanilla Kubernetes cluster, update the namespace from default to kube-system prior to issuing the kubectl create command.

Install the Snapshot CRDs:

1. Download the files from https://github.com/kubernetes-csi/external-snapshotter/tree/v5.0.1/client/config/crd because Longhorn v1.4.1 uses CSI external-snapshotter v5.0.1
2. Run kubectl create -f client/config/crd.
3. Do this once per cluster.

Install the Common Snapshot Controller:

1. Download the files from https://github.com/kubernetes-csi/external-snapshotter/tree/v5.0.1/deploy/kubernetes/snapshot-controller because Longhorn v1.4.1 uses CSI external-snapshotter v5.0.1
2. Update the namespace to an appropriate value for your environment (e.g. kube-system)
3. Run kubectl create -f deploy/kubernetes/snapshot-controller.
4. Do this once per cluster.

Note: previously, the snapshot controller YAML files were deployed into the default namespace by default. The updated YAML files are being deployed into kube-system namespace by default. Therefore, we suggest deleting the previous snapshot controller in the default namespace to avoid having multiple snapshot controllers.

See the Usage section from the kubernetes external-snapshotter git repo for additional information.

Add a Default VolumeSnapshotClass

Ensure the availability of the Snapshot CRDs. Afterwards create a default VolumeSnapshotClass.

# Use v1 as an example
kind: VolumeSnapshotClass
apiVersion: snapshot.storage.k8s.io/v1
metadata:
  name: longhorn
driver: driver.longhorn.io
deletionPolicy: Delete