EX280 Storage And Persistent Volumes — 20 Questions

Question 1

You are creating a StorageClass and want to ensure that PersistentVolumes created by it are only deleted when the PVC is explicitly deleted, rather than retaining them. Which parameter should you set?

Accepted Answer

reclaimPolicy: Retain. The reclaimPolicy field in a StorageClass controls what happens to the underlying PV when its PVC is deleted. Setting it to Retain ensures data persistence.

Answer

deletionPolicy: Retain

Answer

persistentVolumeReclaimPolicy: Keep

Question 2

Which object acts as a cluster-scoped abstraction that defines and parameterizes the type of storage (such as provisioner, parameters, and reclaim policy) that can be dynamically provisioned in OpenShift?

Accepted Answer

VolumeSnapshotClass. A StorageClass defines the provisioner and parameters used to dynamically provision PersistentVolumes.

Answer

PersistentVolume

Answer

PersistentVolumeClaim

Question 3

You are troubleshooting a PVC that remains unbound. You run 'oc describe pvc my-pvc' and see that the storageClassName is set to a class that was recently deleted. What is the correct way to fix this?

Accepted Answer

Recreate the deleted StorageClass with the exact same name.. PVCs cannot have their storageClassName mutated once created. The correct procedure is to delete the PVC and recreate it referencing a valid, existing StorageClass.

Answer

Edit the PVC spec and change the storageClassName field to a valid class.

Answer

Annotate the PVC with 'storageclass.kubernetes.io/override'.

Question 4

Which TWO conditions must be met for a PVC to successfully bind to a dynamically provisioned PersistentVolume?

Accepted Answer

The StorageClass name specified in the PVC must match the StorageClass of the provisioned PV.. The PVC and PV must match in storage class, requested size/access modes, and volume mode compatibility.

Answer

The PVC must belong to the kube-system namespace.

Question 5

Which THREE tasks must an administrator perform to enable volume snapshots in an OpenShift cluster using a CSI driver that supports snapshots?

Accepted Answer

Deploy the Volume Snapshot Controller (if not managed by the CSI operator).. Enabling snapshots requires installing the Volume Snapshot CRDs, deploying the external snapshot controller operator/controller, and creating a VolumeSnapshotClass.

Answer

Format all worker nodes with XFS filesystems.

Question 6

A developer requests a PersistentVolumeClaim using ReadWriteMany access mode. Which default storage type in a standard AWS ODF (OpenShift Data Foundation) deployment natively supports RWX?

Accepted Answer

openshift-storage.cephfs.csi.ceph.com. CephFS, provided by OpenShift Data Foundation, supports ReadWriteMany (RWX) access modes, unlike standard AWS EBS CSI (which is RWO).

Answer

openshift-storage.rbd.csi.ceph.com

Answer

gp2-csi.storage.k8s.io

Answer

ebs.csi.aws.com

Question 7

A user creates a VolumeSnapshot and notices that the resulting VolumeSnapshotContent status is marked as readyToUse: false. What is the most likely cause?

Accepted Answer

The PVC being snapshotted has active writes and the storage backend is still synchronizing snapshot data.. The CSI driver or storage backend has not finished creating the snapshot or data protection sync, or the underlying storage controller hasn't reported back readiness yet.

Answer

The VolumeSnapshot object must be manually promoted before it becomes ready.

Answer

The VolumeSnapshotClass is missing the deletionPolicy parameter.

Answer

The PVC must be unmounted from all running pods before a snapshot can be marked ready.

Question 8

A stateful application needs its PersistentVolume to be bound only after the pod requesting it is assigned to a specific worker node, to avoid topology mismatch issues. Which StorageClass parameter achieves this?

Accepted Answer

volumeBindingMode: WaitForFirstConsumer. Setting volumeBindingMode to WaitForFirstConsumer delays the binding and provisioning of a PersistentVolume until a pod using the PersistentVolumeClaim is created and scheduled.

Answer

allowVolumeExpansion: true

Answer

volumeBindingMode: Immediate

Answer

bindingMode: Late

Question 9

You need to provide temporary scratch space for a container that shares the pod's lifetime and is cleared when the pod is deleted. Which volume type should you configure in the Pod specification?

Accepted Answer

emptyDir. An emptyDir volume is created when a pod is assigned to a node, and exists as long as that pod is running on that node. It starts empty.

Answer

persistentVolumeClaim

Answer

hostPath

Answer

nfs

Question 10

An administrator needs to provision persistent storage dynamically using an NFS server. Which provisioner is required in the StorageClass definition since OpenShift removed the in-tree NFS provisioner?

Accepted Answer

sig-storage.k8s.io/nfs-subdir-external-provisioner. OpenShift removed in-tree provisioners. The external NFS subdir external provisioner is the standard Red Hat-supported way to dynamically provision NFS volumes.

Answer

nfs.csi.k8s.io

Answer

kubernetes.io/nfs

Answer

openshift.io/nfs-dynamic

Question 11

An administrator needs to increase the size of an existing PVC bound to a gp3 storage class in an OpenShift cluster. What is the mandatory first step before editing the PVC spec?

Accepted Answer

Ensure allowVolumeExpansion: true is set on the corresponding StorageClass.. Before editing the PVC size, the StorageClass must have 'allowVolumeExpansion: true' configured. Otherwise, the volume expansion request will be rejected.

Answer

Manually update the underlying cloud provider disk size via the AWS console.

Answer

Delete the PV and recreate it with the new size.

Answer

Scale down all pods using the PVC to zero replicas.

Question 12

A cluster administrator wants to create a VolumeSnapshot of a database PVC. Which API group must the VolumeSnapshotClass belong to?

Accepted Answer

snapshot.storage.k8s.io. Volume snapshots are managed by the snapshot.storage.k8s.io API group.

Answer

storage.k8s.io

Answer

csi.storage.k8s.io

Answer

volumesnapshot.openshift.io

Question 13

You want to restore an existing VolumeSnapshot into a new PersistentVolumeClaim. Which field in the PVC specification must reference the VolumeSnapshot?

Accepted Answer

dataSource. To restore from a snapshot, the dataSource (or dataSourceRef) field in the PVC spec must point to the VolumeSnapshot object.

Answer

claimRef

Answer

snapshotName

Answer

volumeName

Question 14

A cluster administrator notices that a PVC stuck in the Pending state references a StorageClass with volumeBindingMode set to WaitForFirstConsumer. What action will cause the PVC to bind?

Accepted Answer

Create and schedule a Pod that mounts the PVC.. When volumeBindingMode is WaitForFirstConsumer, the PV is not provisioned or bound until a Pod referencing that PVC is scheduled onto a node.

Answer

Delete the StorageClass and recreate it with Immediate binding mode.

Answer

Restart the kube-apiserver service on the control plane nodes.

Answer

Manually create a PV matching the exact size and labels of the PVC.

Question 15

An administrator needs to inspect all StorageClasses available in an OpenShift cluster using the OpenShift CLI. Which command should be executed?

Accepted Answer

oc get sc. The 'oc get storageclass' (or sc) command lists all StorageClasses defined in the cluster.

Answer

oc describe storageclasses

Answer

oc get pvc

Answer

oc get pv

Question 16

An OpenShift cluster uses a CSI driver that supports volume cloning. A user wants to clone an existing PVC named 'data-pvc' into a new PVC named 'clone-pvc'. How should the dataSource be specified?

Accepted Answer

dataSource: { apiGroup: "", kind: "PersistentVolumeClaim", name: "data-pvc" }. To clone a PVC, the dataSource in the new PVC must reference the existing PVC name and kind 'PersistentVolumeClaim'.

Answer

dataSource: { apiGroup: "snapshot.storage.k8s.io", kind: "VolumeSnapshot", name: "data-pvc" }

Answer

spec.cloneSource: "data-pvc"

Answer

spec.volumeName: "data-pvc"

Question 17

A developer deploys a pod with an emptyDir volume. The application running inside writes temporary files. What happens to these files when the container crashes and restarts within the same pod?

Accepted Answer

The files are preserved because emptyDir lifetime is tied to the pod, not individual containers.. An emptyDir volume survives container crashes and restarts; it is only deleted when the pod itself is removed from the node.

Answer

The files are backed up to the cluster control plane automatically.

Answer

The files are deleted immediately because the container filesystem is ephemeral.

Answer

The volume is unmounted and reattached via the CSI driver.

Question 18

An administrator needs to set a default StorageClass for the entire OpenShift cluster so that PVCs without a storageClassName specified automatically use it. How is this configured?

Accepted Answer

By adding the annotation storageclass.kubernetes.io/is-default-class: "true" to the StorageClass object.. Annotating a StorageClass with 'storageclass.kubernetes.io/is-default-class: "true"' makes it the default storage class.

Answer

By modifying the kube-controller-manager operator configuration.

Answer

By naming the StorageClass 'default-sc' exactly.

Answer

By setting defaultStorageClass: true in the cluster-config ConfigMap.

Question 19

Which access mode specifies that a volume can be mounted as read-write by a single node?

Accepted Answer

ReadWriteOnce. ReadWriteOnce (RWO) allows a volume to be mounted as read-write by a single node.

Answer

WriteOnceMany

Answer

ReadOnlyMany

Answer

ReadWriteMany

Question 20

Which command allows an administrator to view details, including events and current binding status, of a specific PersistentVolume named 'pv-data01'?

Accepted Answer

oc describe pv pv-data01. The 'oc describe pv pv-data01' command displays detailed information and recent events for the PersistentVolume.

Answer

oc status pv-data01

Answer

oc get pv pv-data01 -o yaml

Answer

oc logs pv/pv-data01