Skip to main content

Work with volume group snapshots

Contributors netapp-aruldeepa
PDFs

Kubernetes volume group snapshots of Persistent Volumes (PVs) NetApp Trident provides the ability to create snapshots of multiple volumes ( a group of volume snapshots). This volume group snapshot represents copies from multiple volumes that are taken at the same point-in-time.

Note VolumeGroupSnapshot is a beta feature in Kubernetes with beta APIs. Kubernetes 1.32 is the minimum version required for VolumeGroupSnapshot.

Create volume group snapshots

Volume group snapshot is supported with the ontap-san driver, only for iSCSI protocol, not yet supported with Fibre Channel (FCP) nor NVMe/TCP.
.Before you begin

  • Ensure that your Kubernetes version is K8s 1.32 or higher.

  • You must have an external snapshot controller and Custom Resource Definitions (CRDs) to work with snapshots. This is the responsibility of the Kubernetes orchestrator (for example: Kubeadm, GKE, OpenShift).

    If your Kubernetes distribution does not include the external snapshot controller and CRDs, refer to Deploy a volume snapshot controller.

    Note Don't create a snapshot controller if creating on-demand volume group snapshots in a GKE environment. GKE uses a built-in, hidden snapshot controller.

  • In the snapshot controller YAML, set the CSIVolumeGroupSnapshot feature gate to 'true' to ensure that volume group snapshot is enabled.

  • Create the required volume group snapshot classes before creating a volume group snapshot.

  • Ensure that all PVCs/volumes are on the same SVM to be able to create VolumeGroupSnapshot.

Steps

  • Create a VolumeGroupSnapshotClass prior to creating a VolumeGroupSnapshot. For more information, refer to VolumeGroupSnapshotClass.

    apiVersion: groupsnapshot.storage.k8s.io/v1beta1
kind: VolumeGroupSnapshotClass
metadata:
  name: csi-group-snap-class
  annotations:
    kubernetes.io/description: "Trident group snapshot class"
driver: csi.trident.netapp.io
deletionPolicy: Delete

  • Create PVCs with required labels using existing storage classes, or add these labels to existing PVCs.

    The following example creates the PVC using pvc1-group-snap as the data source and label consistentGroupSnapshot: groupA. Define the label key and value based on your requirements.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1-group-snap
  labels:
    consistentGroupSnapshot: groupA
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 100Mi
  storageClassName: sc1-1

  • Create a VolumeGroupSnapshot with the same label (consistentGroupSnapshot: groupA) specified in the PVC.

    This example creates a volume group snapshot:

apiVersion: groupsnapshot.storage.k8s.io/v1beta1
kind: VolumeGroupSnapshot
metadata:
  name: "vgs1"
  namespace: trident
spec:
  volumeGroupSnapshotClassName: csi-group-snap-class
  source:
    selector:
      matchLabels:
        consistentGroupSnapshot: groupA

Recover volume data using a group snapshot

You can restore individual Persistent Volumes using the individual snapshots which have been created as part of the Volume Group Snapshot. You cannot recover the Volume Group Snapshot as a unit.

Use the volume snapshot restore ONTAP CLI to to restore a volume to a state recorded in a prior snapshot.

cluster1::*> volume snapshot restore -vserver vs0 -volume vol3 -snapshot vol3_snap_archive
Note When you restore a snapshot copy, the existing volume configuration is overwritten. Changes made to volume data after the snapshot copy was created are lost.

In-place volume restoration from a snapshot

Trident provides rapid, in-place volume restoration from a snapshot using the TridentActionSnapshotRestore (TASR) CR. This CR functions as an imperative Kubernetes action and does not persist after the operation completes.

For more information, see In-place volume restoration from a snapshot.

Delete a PV with associated group snapshots

When deleting a group volume snapshot:

  • You can delete VolumeGroupSnapshots as a whole, not individual snapshots in the group.

  • If PersistentVolumes are deleted while a snapshot exists for that PersistentVolume, Trident will move that volume to a "deleting" state because the snapshot must be removed before the volume can be safely removed.

  • If a clone has been created using a grouped snapshot and then the group is to be deleted, a split-on-clone operation will begin and the group cannot be deleted until the split is complete.

Deploy a volume snapshot controller

If your Kubernetes distribution does not include the snapshot controller and CRDs, you can deploy them as follows.

Steps

  1. Create volume snapshot CRDs.

    cat snapshot-setup.sh
    #!/bin/bash
# Create volume snapshot CRDs
kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-8.2/client/config/crd/groupsnapshot.storage.k8s.io_volumegroupsnapshotclasses.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-8.2/client/config/crd/groupsnapshot.storage.k8s.io_volumegroupsnapshotcontents.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-8.2/client/config/crd/groupsnapshot.storage.k8s.io_volumegroupsnapshots.yaml

  2. Create the snapshot controller.

    kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-8.2/deploy/kubernetes/snapshot-controller/rbac-snapshot-controller.yaml
    kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-8.2/deploy/kubernetes/snapshot-controller/setup-snapshot-controller.yaml
    Note If necessary, open deploy/kubernetes/snapshot-controller/rbac-snapshot-controller.yaml and update namespace to your namespace.