CKAD Practice Test 2 — 10 Questions

Question 1

You have a Pod with two containers: a main application and a sidecar that handles logging. The sidecar needs access to the same log files as the main application. Which volume type allows both containers to share files?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

emptyDir. An `emptyDir` volume is created when a Pod is assigned to a node and exists as long as the Pod runs, allowing both containers in the same Pod to mount and share the same directory. This is the simplest and most appropriate volume type for sharing ephemeral data, such as log files, between a main application and a sidecar container within the same Pod.

Answer

persistentVolumeClaim

Answer

hostPath

Answer

configMap

Question 2

A Pod spec includes 'securityContext' with 'runAsUser: 1000' and 'runAsGroup: 3000'. The container process inside the pod is expected to write to a mounted volume. Which securityContext field should be set to ensure the volume's group ownership is 3000?

Accepted Answer

fsGroup: 3000. The `fsGroup` field in the Pod's `securityContext` specifies the group ID (GID) that Kubernetes should assign to any volume mounted into the Pod. When `fsGroup: 3000` is set, Kubernetes recursively changes the ownership of the volume's files and directories to group ID 3000, and any new files created by the container process will inherit that group ownership. This ensures the container process, which runs with `runAsGroup: 3000`, can write to the volume without permission errors.

Answer

supplementalGroups: [3000]

Answer

fsGroup: 1000

Answer

runAsGroup: 3000

Question 3

A pod in the 'production' namespace is in a CrashLoopBackOff state. The pod has been running successfully for several days. You run 'kubectl describe pod app-pod -n production' and see the message: 'OOMKilled'. What is the MOST appropriate action to resolve this issue?

Accepted Answer

Increase the memory limit in the pod's container resource specification. The 'OOMKilled' message indicates the container was terminated because it exceeded its memory limit. Increasing the memory limit in the pod's container resource specification allows the container to use more memory, resolving the out-of-memory condition and preventing future crashes.

Answer

Delete and recreate the pod to clear the crash loop

Answer

Increase the CPU request for the container

Answer

Delete the namespace and redeploy all workloads

Question 4

You have a ConfigMap named 'app-config' with key 'database.url'. Which environment variable definition correctly injects this value into a pod using a configMapKeyRef?

Accepted Answer

- name: DATABASE_URL
  valueFrom:
    configMapKeyRef:
      name: app-config
      key: database.url. It properly defines an environment variable with a name and uses `valueFrom.configMapKeyRef` to reference the specific key 'database.url' from the ConfigMap 'app-config'. The `name` field is required in the env entry to specify the environment variable name. Option D is incorrect because it omits the `name` field, making the definition incomplete.

Answer

envFrom:
- configMapRef:
    name: app-config

Answer

- name: DATABASE_URL
  valueFrom:
    secretKeyRef:
      name: app-config
      key: database.url

Answer

- valueFrom:
    configMapKeyRef:
      name: app-config
      key: database.url

Question 5

You have a Deployment with a liveness probe that fails intermittently, causing the pod to restart. You want to reduce the sensitivity of the probe so that it only restarts after 3 consecutive failures. Which probe parameter should you adjust?

Accepted Answer

failureThreshold. The `failureThreshold` parameter defines the number of consecutive probe failures required before Kubernetes considers the probe to have failed and triggers the configured action (e.g., restarting the container). By default, this value is 3, but if it is set lower (e.g., 1), a single failure causes a restart. Increasing `failureThreshold` to 3 (or higher) ensures that the liveness probe only restarts the pod after three consecutive failures, thereby reducing sensitivity to transient issues.

Answer

initialDelaySeconds

Answer

periodSeconds

Answer

successThreshold

Question 6

You have a pod with two containers: one runs a web server, and the other is a sidecar that logs the web server's output to a central logging system. Which pattern does this represent?

Accepted Answer

Sidecar pattern. The sidecar pattern involves deploying a helper container alongside the main application container within the same pod. In this scenario, the sidecar container consumes the web server's logs (e.g., by tailing a shared volume or reading stdout/stderr) and forwards them to a central logging system, such as Elasticsearch or Fluentd. This pattern is a core Kubernetes design principle for extending or enhancing the main container without modifying its code.

Answer

Decorator pattern

Answer

Ambassador pattern

Answer

Adapter pattern

Question 7

You need to debug a pod that is running but not serving traffic. You want to add a temporary container with networking tools to the pod. Which command should you use?

Accepted Answer

kubectl debug mypod --image=busybox -it. `kubectl debug` allows you to add an ephemeral container (a temporary container with networking tools) to an existing running pod without restarting it. This is the only command that directly injects a new container into the pod's network namespace, enabling debugging of network issues while the original container continues running.

Answer

kubectl run debug --image=busybox -it --restart=Never -- /bin/sh

Answer

kubectl attach mypod

Answer

kubectl exec -it mypod -- /bin/sh

Question 8

You are tasked with running a batch job that processes 100 items in parallel, using a Kubernetes Job. The Job should ensure that all items are processed even if some pods fail, and the total number of pod failures should be limited to 3. Which Job configuration is correct?

Accepted Answer

Set spec.parallelism: 100, spec.completions: 100, spec.backoffLimit: 3. Setting `spec.parallelism: 100` allows 100 pods to run concurrently, `spec.completions: 100` ensures all 100 items are processed (each pod handles one item), and `spec.backoffLimit: 3` limits the total number of pod failures to 3 before the Job is marked as failed. This configuration guarantees that even if some pods fail, the Job will retry them up to the specified backoff limit, ensuring all items are processed.

Answer

Set spec.parallelism: 1, spec.completions: 100, spec.backoffLimit: 3

Answer

Set spec.parallelism: 100, spec.completions: 1, spec.backoffLimit: 3

Answer

Set spec.parallelism: 100, spec.completions: 100, spec.activeDeadlineSeconds: 300

Question 9

You need to debug a pod that has no running containers because it is in a CrashLoopBackOff state. You want to start an ephemeral container with debugging tools in the same namespace. Which command accomplishes this?

Accepted Answer

kubectl debug -it pod-name --image=busybox --target=container-name. `kubectl debug` allows you to start an ephemeral container in an existing pod that is in a CrashLoopBackOff state. The `--target` flag attaches the ephemeral container to the same Linux namespace as the specified container, enabling debugging without restarting the pod. This is the only command that works when the pod has no running containers and `kubectl exec` fails.

Answer

kubectl run debug --image=busybox -it --restart=Never

Answer

kubectl attach pod-name

Answer

kubectl exec -it pod-name -- /bin/sh

Question 10

A pod in the 'production' namespace is in a CrashLoopBackOff state. The pod has been running successfully for several days. You run 'kubectl describe pod app-pod -n production' and see the message: 'OOMKilled'. What is the MOST appropriate action to resolve this issue?

Accepted Answer

Increase the memory limit in the pod's container resource specification. The pod is in CrashLoopBackOff with an OOMKilled message, which means the container's memory usage exceeded its configured memory limit. The most appropriate action is to increase the memory limit in the pod's container resource specification so the container has enough memory to run without being terminated by the Out-Of-Memory (OOM) killer.

Answer

Delete and recreate the pod to clear the crash loop

Answer

Increase the CPU request for the container

Answer

Delete the namespace and redeploy all workloads