If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.

If you are not familiar with Volume Snapshots, check out my article OpenShift - Getting Started with Volume Snapshots.

This assumes you have already

• Created a Persistent Volume
• Created a Persistent Volume Claim
• Created a Storage Class

A persistent volume (PV) is the "physical" volume (such as a hard disk drive or solid state drive) on the host machine (node) that stores your persistent data, whereas a persistent volume claim (PVC) is a reference to a persistent volume, used by a pod.

Persistent Volume Claims

The oc get persistentvolumeclaims command will return the list of Persistent Volume Claims. Let's say you have a Persistent Volume Claim named my-pvc.

TIP

The -A or --all-namespaces flag can be used to list the Persistent Volume Claims in every project / namespace.

The -n or --namespace flag can be used to list the Persistent Volume Claims in a certain project / namespace.

]$ oc get persistentvolumeclaims --all-namespaces
NAMESPACE     NAME      STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   VOLUMEATTRIBUTESCLASS   AGE
my-project    my-pvc    Bound    pvc-816c11cc-c30d-40b2-9a5b-25f6a2203475   10Gi       RWX            thin-cli       <unset>                 299d

Storage Class

Notice in this example that Persistent Volume Clain my-pvc is using Storage Class thin-csi. The oc get StorageClasses command can be used to list the Storage Classes that have been added to your OpenShift cluster. By the way, CSI stands for Container Storage Interface. Notice in this example that Storage Class thin-cli maps to provisioner csi.vsphere.vmware.com.

]$ oc get StorageClasses
NAME                     PROVISIONER                    RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
file-storage (default)   csi.trident.netapp.io          Delete          Immediate              true                   654d
thin                     kubernetes.io/vsphere-volume   Delete          Immediate              false                  657d
thin-csi                 csi.vsphere.vmware.com         Delete          WaitForFirstConsumer   true                   657d

Volume Storage Class

Let's say you want to create a volume snapshot of my-pvc. In this example, since Persistent Volume Claim my-pvc is using Storage Class thin-csi and Storage Class thin-csi maps to provisioner csi.vsphere.vmware.com a Volume Snapshot Class for csi.vsphere.vmware.com will be needed. Let's say you have the following in a YAML file.

apiVersion: snapshot.storage.k8s.io/v1
deletionPolicy: Delete
driver: csi.vsphere.vmware.com
kind: VolumeSnapshotClass
metadata:
  annotations:
    snapshot.storage.kubernetes.io/is-default-class: "true"
  name: csi-vsphere-vsc

The oc apply command can be used to create the Volume Snapshot Class from the YAML file.

oc apply --filename csi-vsphere-vsc.yaml

Or in the OpenShift console, at Storage > VolumeStorageClasses you can click on the Create VolumeSnapshotClass button.

And now the oc get VolumeSnapshotClasses command can be used to confirm that the Volume Snapshot Class exists.

]$ oc get VolumeSnapshotClasses
NAME              DRIVER                   DELETIONPOLICY   AGE
csi-vsphere-vsc   csi.vsphere.vmware.com   Delete           2m5s

Or you can see this in the OpenShift console at Storage > VolueSnapshotClasses.