EX280 Storage And Persistent Volumes Practice Test 3 — 15 Questions

Question 1

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.. In Kubernetes and OpenShift, a StorageClass is marked as the cluster default by adding the annotation storageclass.kubernetes.io/is-default-class: "true" to its metadata. The PersistentVolumeClaim admission controller then automatically assigns that class to any PVC that omits storageClassName.

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 2

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

Accepted Answer

ReadWriteOnce. ReadWriteOnce (RWO) is the access mode that allows a PersistentVolume to be mounted as read-write by a single node at a time. This is the most common mode for block-backed storage such as AWS EBS, GCE PD, and Ceph RBD, where the underlying device cannot be safely shared across nodes. It does not restrict the number of pods on that node — multiple pods on the same node can share the volume.

Answer

WriteOnceMany

Answer

ReadOnlyMany

Answer

ReadWriteMany

Question 3

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 retrieves detailed information about the PersistentVolume, including its status, capacity, access modes, reclaim policy, and associated events, which is exactly what the administrator needs. The describe subcommand aggregates the object's spec, status, and recent events into a human-readable format.

Answer

oc status pv-data01

Answer

oc get pv pv-data01 -o yaml

Answer

oc logs pv/pv-data01

Question 4

What is the primary function of a CSI (Container Storage Interface) Driver Operator in OpenShift?

Accepted Answer

To deploy, upgrade, and manage the CSI driver components (controller and node plugins) in the cluster.. A CSI Driver Operator in OpenShift is responsible for deploying, upgrading, and managing the lifecycle of a CSI driver's components — specifically the controller plugin (Deployment) and node plugin (DaemonSet) — in the cluster. It packages the driver as an Operator so that installation, configuration, and upgrades are handled declaratively via the Operator Lifecycle Manager (OLM).

Answer

To automatically back up etcd data onto persistent volumes.

Answer

To act as an NFS server running directly on control plane nodes.

Answer

To convert emptyDir volumes into encrypted block devices.

Question 5

An administrator is configuring ephemeral storage limits for containers in a namespace. Where must these limits be defined to enforce maximum local scratch space usage per container?

Accepted Answer

LimitRange. LimitRange objects define per-container (and per-pod) default, minimum, and maximum resource constraints — including ephemeral-storage — within a namespace. To enforce a maximum local scratch space per container, you set the ephemeral-storage max in a LimitRange, which the API server enforces at admission time. ResourceQuota, by contrast, caps aggregate namespace usage, not per-container limits.

Answer

ResourceQuota

Answer

StorageClass

Answer

PersistentVolumeClaim

Question 6

An administrator expands a PVC from 10Gi to 50Gi. The underlying cloud storage volume is successfully resized, but inside the running pod, 'df -h' still reports the size as 10Gi. What is the most likely reason?

Accepted Answer

The file system on the volume has not been expanded to occupy the new block storage capacity.. When a PVC is expanded, the CSI driver resizes the underlying block volume, but the filesystem inside the volume must also be expanded to use the new space. For filesystems like ext4 or XFS, this requires a resize operation (resize2fs or xfs_growfs), which is typically triggered by the kubelet when the pod is restarted or when the CSI driver supports online expansion. If the filesystem resize hasn't occurred, 'df -h' inside the pod still reports the old size.

Answer

The pod must be restarted to flush the Linux page cache.

Answer

The StorageClass lacks the allowVolumeExpansion parameter.

Answer

PVC expansion is strictly read-only after creation and cannot be updated at the filesystem level.

Question 7

You are examining a PersistentVolume in OpenShift and notice its status is Released. What does this indicate?

Accepted Answer

The PVC associated with the PV has been deleted, but the volume has not yet been reclaimed.. A PersistentVolume in Released state means its bound PersistentVolumeClaim was deleted, but the PV has not yet been reclaimed or recycled. The PV still holds the data and remains unavailable for new claims until an administrator manually intervenes (e.g., deletes and recreates the PV, or clears the claimRef). This is distinct from Available (ready for binding) and Bound (actively attached to a PVC).

Answer

The PV is currently bound to an active PVC and is in use by a running pod.

Answer

The PV has failed its health check and has been quarantined by the CSI driver.

Answer

The PV is available for binding by any new incoming PVC request.

Question 8

Which field in a PersistentVolumeClaim specifies the minimum amount of storage space required by the workload?

Accepted Answer

spec.resources.requests.storage. In a PVC, the requested storage size is specified under spec.resources.requests.storage, following the standard Kubernetes resource requirements schema. This value is matched against a PV's capacity during binding, and the resulting PV must be at least this size. It is the same pattern used for CPU and memory requests in pod specs.

Answer

spec.storageSize

Answer

spec.capacity.storage

Answer

spec.volumeSize

Question 9

An administrator creates a StorageClass with volumeBindingMode: WaitForFirstConsumer. A user creates a PVC using this StorageClass. What will be the initial phase of the PVC?

Accepted Answer

Pending. When a StorageClass has volumeBindingMode: WaitForFirstConsumer, the PVC will remain in the Pending phase until a pod that uses it is scheduled. This is because the volume binding is delayed until the pod's scheduling requirements are known, allowing the volume to be provisioned in the same zone as the pod.

Answer

Provisioning

Answer

Bound

Answer

Available

Question 10

Which OpenShift CLI command is used to display all PersistentVolumeClaims in the current project along with their bound PersistentVolumes and storage classes?

Accepted Answer

oc get pvc. 'oc get pvc' lists all PersistentVolumeClaims in the current project, and its default output includes the STATUS, VOLUME (the bound PV name), CAPACITY, ACCESS MODES, and STORAGECLASS columns. This single command gives the administrator the PVC-to-PV-to-StorageClass mapping requested.

Answer

oc get pv

Answer

oc get sc

Answer

oc describe volume

Question 11

An administrator configures a Pod with a volume type of hostPath. What is a key security risk or operational limitation of using hostPath in a production multi-tenant OpenShift cluster?

Accepted Answer

Pods using hostPath can access node filesystems, breaking container isolation and posing security risks.. A hostPath volume mounts a directory or file from the node's filesystem directly into the pod. This breaks the container isolation boundary because the pod can read or write node-level files — including /etc, /var/lib/kubelet, or the container runtime socket — enabling privilege escalation, data exfiltration, or node compromise. In multi-tenant clusters this is a serious security risk.

Answer

hostPath volumes automatically expire and delete data after 24 hours.

Answer

hostPath requires an external CSI driver to be installed.

Answer

hostPath is incompatible with Linux nodes and only works on Windows worker nodes.

Question 12

Where are PersistentVolumeClaims located in terms of OpenShift's API scope?

Accepted Answer

They are namespaced resources.. PersistentVolumeClaims (PVCs) are namespaced resources in OpenShift, meaning they exist within a specific project (namespace) and are scoped to that namespace. This allows different projects to have their own PVCs with the same name.

Answer

They are node-scoped resources.

Answer

They are global resources shared across all clusters in a fleet.

Answer

They are cluster-scoped resources.

Question 13

An administrator wants to use raw block storage (Block Volume Mode) rather than a mounted filesystem for a high-performance database running on OpenShift. How should the volume mode be specified in the PersistentVolumeClaim?

Accepted Answer

volumeMode: Block. Raw block storage is requested by setting 'volumeMode: Block' in the PersistentVolumeClaim spec. This tells the CSI driver and kubelet to expose the volume as an unformatted block device (e.g., /dev/xvda) inside the pod rather than mounting a filesystem, which is required for databases that manage their own I/O and formatting.

Answer

mountOptions: [ "raw" ]

Answer

accessMode: RawBlock

Answer

storageType: Unformatted

Question 14

An administrator is reviewing PersistentVolumes and notices several PVs stuck in a Terminating state. What is the most common reason a PV cannot be deleted immediately?

Accepted Answer

The volume attachment object still holds an active lock, or a finalizer prevents deletion until unmounted.. A PersistentVolume in a Terminating state is almost always waiting on the Kubernetes volume lifecycle controller to finish detaching the volume from any node that still has it mounted. The VolumeAttachment object holds a lock, and the PV carries the `kubernetes.io/pv-protection` finalizer, which the controller removes only after the volume is fully unmounted and detached. Until that happens, the API server cannot complete deletion, so the PV remains stuck in Terminating.

Answer

etcd disk space is full.

Answer

The project quota has been exceeded.

Answer

The apiserver cache is corrupted and requires a cluster reboot.

Question 15

A cluster administrator needs to configure a generic ephemeral inline volume in a Pod specification. Where is the volume defined?

Accepted Answer

Directly in the Pod's spec.volumes array using the ephemeral volume source type.. A generic ephemeral inline volume is defined directly in the Pod's spec.volumes array using the ephemeral volume source type. This allows the volume to be created and destroyed alongside the Pod, with the underlying storage managed by a PersistentVolumeClaim template embedded in the Pod spec. The ephemeral volume source references a volumeClaimTemplate that specifies the StorageClass and size, enabling dynamic provisioning without a separate PVC object.

Answer

In the namespace ResourceQuota configuration.

Answer

In the StorageClass definition under the ephemeralTemplate field.

Answer

As a standalone PVC that is automatically annotated by the scheduler.