CKAD Application Design and Build Practice Test 2 — 15 Questions

Question 1

A developer wants to create a Job that runs exactly 3 pods in parallel. Which field should be set in the Job spec?

Accepted Answer

spec.parallelism: 3. `spec.parallelism` in a Kubernetes Job spec defines the desired number of Pods that should run concurrently. Setting `spec.parallelism: 3` tells the Job controller to run exactly 3 Pods in parallel, meeting the requirement of running 3 pods simultaneously.

Answer

spec.ttlSecondsAfterFinished: 3

Answer

spec.backoffLimit: 3

Answer

spec.completions: 3

Question 2

In a Dockerfile, what is the difference between CMD and ENTRYPOINT?

Accepted Answer

ENTRYPOINT defines the executable and CMD provides default arguments. C is correct because in a Dockerfile, ENTRYPOINT specifies the executable that will always run when the container starts, while CMD provides default arguments that can be overridden. When both are defined, CMD arguments are appended to the ENTRYPOINT command, allowing flexible default behavior that users can modify at runtime via the command line.

Answer

CMD always runs, ENTRYPOINT can be overridden

Answer

There is no difference; they are interchangeable

Answer

CMD is used for shell form, ENTRYPOINT for exec form

Question 3

A user runs: kubectl apply -f job.yaml. The Job spec has backoffLimit: 0. The pod fails immediately. What happens?

Accepted Answer

The Job enters a Failed state. When `backoffLimit: 0` is set in a Job spec and the pod fails immediately, the Job controller does not retry the pod because the backoff limit is zero. According to Kubernetes Job semantics, the Job is considered failed once the number of failures reaches the `backoffLimit` (0 in this case), so the Job transitions to a Failed state without any further pod creation or retries.

Answer

The Job is retried indefinitely

Answer

The pod is restarted until it succeeds

Answer

A new pod is created automatically

Question 4

An administrator creates a Pod with an ephemeral container using 'kubectl debug my-pod -it --image=busybox --target=my-container'. The ephemeral container shares the same process namespace as the target container. Which flag enables this?

Accepted Answer

--target. The `--target` flag in `kubectl debug` specifies the target container within the Pod for the ephemeral container. When used, the ephemeral container shares the same process namespace as the target container, allowing tools like `ps` to see processes from the target container. This is essential for debugging scenarios where you need to inspect or interact with the target container's processes.

Answer

--container

Answer

--namespace

Answer

--share-process-namespace

Question 5

Which Kubernetes API version is used for creating a CronJob?

Accepted Answer

batch/v1. CronJob is a Kubernetes resource that was promoted to a stable API version in Kubernetes 1.21. The correct API version for creating a CronJob is batch/v1, as it is the current stable version. The batch/v1beta1 version is deprecated and removed in Kubernetes 1.25, so batch/v1 is the correct choice for CKAD exam scenarios.

Answer

batch/v1beta1

Answer

cron/v1

Answer

apps/v1

Question 6

Which TWO statements about Init Containers are correct? (Select exactly 2.)

Accepted Answer

Init containers run to completion sequentially before any app containers start. Init containers run to completion sequentially before any app containers start (B). They can use a different container image than the app containers (C). Option D is incorrect: if the Pod's restartPolicy is Never, a failing init container causes the Pod to fail and the init container is not restarted; it does not always restart regardless of restartPolicy. Therefore, only options B and C are correct.

Answer

Init containers run in parallel to reduce startup time

Answer

If an init container fails, Kubernetes restarts it until it succeeds regardless of restartPolicy

Answer

Init containers can have liveness and readiness probes

Question 7

A team wants to deploy a multi-container Pod with a sidecar pattern. Which THREE statements are true about sidecar containers? (Select exactly 3.)

Accepted Answer

Sidecar containers are used for tasks like log collection, service mesh proxies, or data synchronization. Sidecar containers are auxiliary containers that enhance or extend the functionality of the main application container. Common use cases include log collection (e.g., Fluentd), service mesh proxies (e.g., Envoy), and data synchronization (e.g., rsync or a Git sync sidecar). These tasks support the primary workload without altering its code.

Answer

Sidecar containers are always started before the main container

Answer

Sidecar containers can be updated independently without restarting the main container

Question 8

A developer is creating a CronJob that should not start a new job if the previous one is still running. Which TWO configurations achieve this? (Select exactly 2.)

Accepted Answer

Set concurrencyPolicy: Forbid. Setting `concurrencyPolicy: Forbid` explicitly tells Kubernetes to skip creating a new job if the previous job from the CronJob is still running. This prevents overlapping executions, which is exactly the requirement. The `Forbid` policy is the standard Kubernetes mechanism for ensuring at-most-once execution per scheduled interval.

Answer

Set concurrencyPolicy: Allow

Answer

Set startingDeadlineSeconds to a low value

Answer

Set concurrencyPolicy: Replace

Question 9

Which Dockerfile instruction is used to specify the base image for a container image?

Accepted Answer

FROM. The FROM instruction initializes a new build stage and sets the base image for subsequent instructions. It must be the first non-comment instruction in a Dockerfile, pulling a specified image from a registry (e.g., Docker Hub) to provide the filesystem and runtime environment for the container.

Answer

COPY

Answer

CMD

Answer

RUN

Question 10

A developer is writing a Dockerfile and wants to ensure that the container runs a Python script named 'app.py' as its main process. Which instruction should be used?

Accepted Answer

ENTRYPOINT ["python", "app.py"]. ENTRYPOINT defines the executable that runs as the main process in the container. When combined with CMD (or used alone in exec form), it ensures that 'python app.py' is the primary process with PID 1, which is essential for proper signal handling and container lifecycle management.

Answer

EXPOSE 8080

Answer

CMD ["python", "app.py"]

Answer

RUN ["python", "app.py"]

Question 11

A Kubernetes pod has two containers: a main application container and a sidecar container running a logging agent. The sidecar container is expected to start before the main container because it needs to initialize a shared log directory. What Kubernetes feature ensures this ordering?

Accepted Answer

Init containers. Init containers run to completion before app containers start, ensuring order.

Answer

Lifecycle hooks

Answer

Readiness probe on the sidecar

Answer

Resource limits

Question 12

You have a multi-stage Docker build. The first stage compiles a binary, and the second stage copies the binary from the first stage. What is the correct COPY syntax to copy a file named 'app' from the first stage named 'builder'?

Accepted Answer

COPY --from=builder app /app/. The `--from=builder` flag in the COPY instruction allows you to copy files from a specific build stage (named 'builder') in a multi-stage Docker build. This syntax is essential for multi-stage builds, where the first stage compiles artifacts and the second stage copies only the necessary binaries, reducing final image size.

Answer

COPY app /app/

Answer

COPY --stage=builder app /app/

Answer

COPY source=builder app /app/

Question 13

What is the purpose of the '.dockerignore' file?

Accepted Answer

To exclude files from the build context. The `.dockerignore` file is used to exclude files and directories from the build context sent to the Docker daemon during a `docker build` operation. By specifying patterns in this file, you prevent unnecessary or sensitive files (like local development artifacts, `.git` directories, or node_modules) from being included, which speeds up the build and reduces the image size. Option C correctly identifies this purpose.

Answer

To specify which files to include in the image

Answer

To ignore files during docker push

Answer

To list environment variables to ignore

Question 14

A developer wants to tag a local image 'myapp:latest' with the tag 'v1.0.0' for pushing to a registry. Which command does this?

Accepted Answer

docker tag myapp:latest myapp:v1.0.0. The `docker tag` command is used to tag an existing local image with a new tag. After tagging, the image can be pushed to a registry using `docker push`. There is no `kubectl tag` command; Kubectl does not manage local image tagging. `kubectl set image` is used to update the image of a deployment, not to tag a local image.

Answer

docker push myapp:v1.0.0

Answer

kubectl tag myapp:latest myapp:v1.0.0

Answer

kubectl set image myapp:v1.0.0

Question 15

What is the correct apiVersion for a Kubernetes Job in v1.29?

Accepted Answer

batch/v1. Kubernetes Jobs are part of the batch API group, and starting from Kubernetes v1.21, the batch/v1 API version is stable and the only supported version for Jobs. In v1.29, batch/v1beta1 has been removed, so batch/v1 is the correct and required apiVersion.

Answer

batch/v1beta1

Answer

apps/v1

Answer

v1