CKA Practice Test 12 — 15 Questions

Question 1

Which resource type is used to define a template for dynamically provisioning PersistentVolumes?

Accepted Answer

StorageClass. StorageClass is the correct resource because it defines a 'class' of storage with a provisioner (e.g., kubernetes.io/aws-ebs) and parameters that Kubernetes uses to dynamically create PersistentVolumes when a PersistentVolumeClaim requests storage. Without a StorageClass, dynamic provisioning cannot occur, as the cluster needs a template to know which storage backend to use and how to configure it.

Answer

PersistentVolume

Answer

VolumeAttachment

Answer

PersistentVolumeClaim

Question 2

A Pod is configured with a volume that uses a ConfigMap. The ConfigMap is updated after the Pod is running. How can the Pod access the updated data without restarting?

Accepted Answer

The Pod will automatically see the updated data within minutes.. When a ConfigMap is mounted into a Pod as a volume (without using subPath), updates to the ConfigMap are automatically reflected in the Pod's filesystem after a short delay (typically within minutes, controlled by the kubelet's sync period). However, if the ConfigMap is consumed via environment variables or mounted using subPath, the Pod must be restarted to see the changes. In this question, the volume uses a ConfigMap (presumably without subPath), so the Pod will automatically see the updated data within minutes.

Answer

The ConfigMap must be deleted and recreated.

Answer

The Node must be rebooted.

Answer

The Pod must be deleted and recreated.

Question 3

Which of the following is a required field when defining a PersistentVolume?

Accepted Answer

capacity. In Kubernetes, a PersistentVolume (PV) must define its storage capacity using the `capacity` field, which specifies the amount of storage the PV provides (e.g., `storage: 10Gi`). This is a required field because the PV represents a piece of storage in the cluster, and the scheduler and PersistentVolumeClaim (PVC) binding logic need to know the available size to match claims. Without `capacity`, the PV definition is invalid and will be rejected by the API server.

Answer

storageClassName

Answer

nodeAffinity

Answer

persistentVolumeReclaimPolicy

Question 4

You have a PVC that is bound to a PV with a filesystem volume mode. You want to use the volume as a block device in a pod. What should you do?

Accepted Answer

Create a new PVC with volumeMode: Block and bind it to a new PV.. A PVC with `volumeMode: Block` must be created and bound to a PV that also has `volumeMode: Block` to use the volume as a block device in a pod. The existing PVC is bound to a PV with `volumeMode: Filesystem`, which cannot be used as a block device without recreating the underlying storage. You cannot change the volume mode of an existing PV or PVC; you must provision new resources with the correct mode.

Answer

Use a hostPath volume instead.

Answer

Set volumeDevices in the pod spec instead of volumeMounts.

Answer

Modify the PV's volumeMode to Block.

Question 5

A cluster has a CSI driver installed. A pod using a CSI volume is in CrashLoopBackOff. 'kubectl describe pod' shows: 'failed to mount volume: rpc error: code = DeadlineExceeded desc = context deadline exceeded'. What is the MOST likely cause?

Accepted Answer

The CSI driver is failing to respond in time.. The error 'context deadline exceeded' indicates that the CSI driver's gRPC call to mount the volume did not complete within the default timeout (typically 30 seconds). This is most commonly caused by the CSI driver being unresponsive due to resource starvation, network issues, or a bug in the driver itself. Since the CSI driver is installed and the pod is attempting to mount, the failure is in the driver's response time, not in the PVC binding or volume mode.

Answer

The PVC is not bound.

Answer

The CSI driver is not installed.

Answer

The volume mode is Block but the pod expects Filesystem.

Question 6

A developer creates a PVC with storageClassName: "" (empty string). What does this mean?

Accepted Answer

The PVC will only bind to PVs that also have storageClassName: "". When a PVC has `storageClassName: ""` (empty string), it explicitly disables dynamic provisioning and static binding to a PV that also has `storageClassName: ""`. This means the PVC will only bind to a pre-existing PV that has its `storageClassName` set to an empty string, bypassing any default StorageClass. It does not remain pending indefinitely, nor does it use or trigger the default StorageClass.

Answer

The PVC will remain pending indefinitely

Answer

The PVC will use the default StorageClass

Answer

The PVC will be dynamically provisioned using the cluster's default StorageClass

Question 7

What does the 'volumeMode: Block' setting in a PersistentVolume spec indicate?

Accepted Answer

The volume will be presented as a raw block device to the pod. Setting 'volumeMode: Block' in a PersistentVolume spec tells Kubernetes to present the volume as a raw block device (e.g., /dev/sdb) inside the pod, rather than mounting a filesystem. This is defined in the Kubernetes PersistentVolume API and is used for applications that need direct access to the underlying storage, such as databases or software that manage their own filesystems.

Answer

The volume will be formatted with a filesystem automatically

Answer

The volume will have encryption enabled by default

Answer

The volume will be mounted using NFS protocol

Question 8

A pod is using a PersistentVolumeClaim (PVC) named 'mypvc' which is bound to a PersistentVolume (PV) with reclaim policy 'Retain'. The pod is deleted and then the PVC is deleted. What happens to the PV?

Accepted Answer

The PV remains but is in 'Released' state.. When a PVC is deleted, the associated PV with a 'Retain' reclaim policy is not automatically deleted or recycled. Instead, the PV transitions to a 'Released' state, indicating that its data is preserved but it is no longer bound to a PVC. The PV remains in the cluster until an administrator manually reclaims it by removing the claimRef or deleting the PV.

Answer

The PV is automatically deleted.

Answer

The PV is immediately bound to another PVC.

Answer

The PV is recycled for reuse.

Question 9

A pod uses a PersistentVolumeClaim named 'claim-log'. The PVC is pending. You run 'kubectl describe pvc claim-log' and see the event: 'waiting for a volume to be created, either by external provisioner or manually'. The StorageClass 'standard' has provisioner: 'kubernetes.io/no-provisioner'. What is the most likely cause?

Accepted Answer

The StorageClass 'standard' does not have a dynamic provisioner configured. The StorageClass 'standard' has provisioner: 'kubernetes.io/no-provisioner', which is a static provisioner that does not automatically create volumes. Since the PVC is pending with the event 'waiting for a volume to be created, either by external provisioner or manually', it indicates that no dynamic provisioner is available to automatically provision a PersistentVolume (PV) for the PVC. The most likely cause is that the StorageClass lacks a dynamic provisioner, so a PV must be manually created or an external provisioner must be configured.

Answer

The StorageClass is missing the volumeBindingMode

Answer

The PVC's access mode is incompatible with the StorageClass

Answer

The PVC requires a larger storage size than any available PV

Question 10

A node in the cluster is showing NotReady status. Which steps should you take to diagnose the issue? (Select the BEST initial step.)

Accepted Answer

Run 'journalctl -u kubelet' on the node to check kubelet logs. When a node is NotReady, the kubelet is the primary agent responsible for reporting node status. The kubelet communicates node conditions to the control plane via periodic heartbeats. Checking the kubelet logs with 'journalctl -u kubelet' on the node itself is the most direct initial step to identify why the kubelet is failing to report readiness, such as network issues, resource exhaustion, or certificate problems.

Answer

Test DNS resolution from a pod on the node

Answer

Run 'kubectl describe pod' for pods on that node

Answer

Check the kube-apiserver logs on the master node

Question 11

A Pod is in 'CrashLoopBackOff' state. You run 'kubectl logs <pod> --previous' and see an error about a missing environment variable. The Pod spec defines the environment variable in a ConfigMap. What is the best next step to diagnose the issue?

Accepted Answer

Run 'kubectl get configmap <configmap-name>' to verify the ConfigMap exists and contains the expected key. The first step in diagnosing a missing environment variable that should come from a ConfigMap is to verify that the ConfigMap itself exists and contains the expected key. If the ConfigMap is missing or the key is absent, the Pod will fail to start or crash, leading to CrashLoopBackOff. Running 'kubectl get configmap' directly confirms whether the resource is present and correctly populated, which is the most efficient next step before deeper investigation.

Answer

Use 'kubectl exec -it <pod> -- env' to list environment variables

Answer

Increase the pod's memory limit to prevent OOM

Answer

Check the node's kubelet logs for errors

Question 12

A pod is in CrashLoopBackOff. You run 'kubectl logs mypod --previous' and see 'Error: unable to connect to database'. What is the MOST likely cause?

Accepted Answer

The database service endpoint is unreachable. The error 'unable to connect to database' indicates a network connectivity issue between the pod and the database service. Since the error is from the application itself (not a Kubernetes probe), the most likely cause is that the database service endpoint is unreachable, either due to a misconfigured service, incorrect DNS resolution, or network policy blocking traffic. The `--previous` flag shows logs from the previous container instance, confirming the application consistently fails to reach the database.

Answer

The pod's readiness probe is failing

Answer

The pod's liveness probe is misconfigured

Answer

The pod is out of memory

Question 13

An administrator needs to configure dynamic provisioning for persistent volumes using an external CSI driver. Which of the following is the correct approach?

Accepted Answer

Create a StorageClass with 'provisioner' set to the CSI driver name.. Dynamic provisioning in Kubernetes requires a StorageClass object that references the CSI driver as its provisioner. When a PVC requests a StorageClass with a CSI provisioner, the CSI external-provisioner sidecar automatically creates a PersistentVolume and binds it to the PVC. Without the StorageClass, Kubernetes has no way to know which CSI driver should handle the provisioning request.

Answer

Set the 'volumeBindingMode' to 'Immediate' in the PVC.

Answer

Install the CSI driver and then all PVCs will automatically be provisioned.

Answer

Create a PersistentVolume with the CSI driver name in the 'csi' section.

Question 14

After deploying a new Deployment, you run 'kubectl get events' and see 'FailedScheduling' events. What is a possible cause?

Accepted Answer

The pod has a node selector that matches no nodes. A FailedScheduling event indicates that the Kubernetes scheduler could not find a suitable node to place the pod. Option B is correct because if a pod has a node selector that does not match any node's labels, the scheduler will fail to schedule it, resulting in a FailedScheduling event. The scheduler evaluates node selectors against node labels, and if no node satisfies the selector, the pod remains unscheduled.

Answer

The container port is already in use on the node

Answer

The node has a taint that tolerates the pod

Answer

The pod's image pull secret is missing

Question 15

You run 'kubectl get pods' and see a pod in 'ImagePullBackOff' state. Which of the following is NOT a common cause?

Accepted Answer

The node has a taint that tolerates the pod. NOT a common cause of ImagePullBackOff because taints and tolerations affect pod scheduling, not image pulling. ImagePullBackOff occurs when the kubelet fails to pull the container image from the registry, which is a runtime issue unrelated to node scheduling constraints.

Answer

The image tag does not exist

Answer

The image registry requires authentication

Answer

The image name is misspelled