CKAD Application Design and Build Practice Test 5 — 15 Questions

Question 1

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 2

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

Question 3

A user runs 'kubectl run nginx --image=nginx --restart=Never' and the pod goes into 'Pending' state. What is a likely reason?

Accepted Answer

The node has insufficient resources to schedule the pod. Pending often indicates resource constraints like insufficient CPU or memory.

Answer

The image name is incorrect

Answer

The pod is missing a readiness probe

Answer

The pod's restart policy is set to Never

Question 4

A CronJob is configured with 'concurrencyPolicy: Forbid'. If a job from the previous schedule is still running when the next scheduled time arrives, what happens?

Accepted Answer

The new job is skipped until the old job completes. When `concurrencyPolicy: Forbid` is set on a CronJob, the CronJob controller will skip creating a new Job if the previous Job from the last schedule is still running. The new Job is effectively skipped (not queued) until the next scheduled time, preventing overlapping executions. This ensures that only one instance of the Job runs at a time.

Answer

The CronJob is suspended

Answer

The new job starts immediately, and the old job is terminated

Answer

Both jobs run concurrently

Question 5

A user creates a Job with '.spec.completions=5' and '.spec.parallelism=2'. How many pods will run at the same time?

Accepted Answer

2. `.spec.parallelism=2` directly specifies the maximum number of Pods that can run concurrently for the Job. The `.spec.completions=5` value only sets the total number of successful completions required, not the parallelism. Therefore, at any given time, only 2 Pods will run simultaneously.

Answer

5

Answer

10

Answer

7

Question 6

You need to debug a pod that has no running container because it crashed. The pod is in CrashLoopBackOff. Which command allows you to start a temporary container in the same pod for debugging?

Accepted Answer

kubectl debug <pod> -it --image=busybox. `kubectl debug` can create an ephemeral container in an existing pod for debugging purposes, even when the original container is in CrashLoopBackOff. The `-it` flag provides an interactive terminal, and `--image=busybox` supplies a lightweight debugging image. This allows you to inspect the pod's filesystem, network, or environment without restarting the failing container.

Answer

kubectl attach <pod>

Answer

kubectl run debug --image=busybox

Answer

kubectl exec -it <pod> -- /bin/bash

Question 7

What is the default restart policy for a pod created with 'kubectl run nginx --image=nginx'?

Accepted Answer

Always. The default restart policy for a Pod created with `kubectl run` is `Always`. This is because `kubectl run` generates a deployment-like controller (or a standalone Pod in older versions) that defaults to the `Always` policy, meaning the kubelet will automatically restart the container regardless of its exit code. This ensures the Pod maintains a running state unless explicitly deleted or scaled down.

Answer

OnFailure

Answer

Never

Answer

Restart

Question 8

Which THREE of the following are valid fields in the '.spec' of a Job manifest?

Accepted Answer

parallelism. 'parallelism' is a valid field in the '.spec' of a Job manifest. It controls the maximum number of Pods that can run concurrently for the Job, allowing you to manage parallel execution. This field is part of the Job specification in the Kubernetes API, distinct from Deployments or other controllers.

Answer

replicas

Answer

strategy

Question 9

A developer wants to containerize a Node.js application. The Dockerfile should first copy only package.json and package-lock.json, run npm install, then copy the rest of the source code. Which Dockerfile best achieves this?

Accepted Answer

COPY package*.json /app/
RUN npm install
COPY . /app/. It first copies only package.json and package-lock.json (using a wildcard pattern), runs `npm install` to leverage Docker's layer caching, and then copies the rest of the source code. This ensures that subsequent builds only re-run `npm install` when the dependency files change, not on every source code modification, which is a best practice for efficient Docker builds.

Answer

COPY . /app
RUN npm install

Answer

ADD package*.json /app/
RUN npm install
ADD . /app/

Answer

ADD . /app
RUN npm install

Question 10

You need to run a database migration as a container before the main application container starts. Which Kubernetes concept should you use?

Accepted Answer

Init container. Init containers run sequentially before the main application container starts and are designed for setup tasks like database migrations. They complete successfully before any regular containers in the Pod begin, ensuring the migration finishes before the main app starts.

Answer

Job

Answer

Sidecar container

Answer

Ephemeral container

Question 11

A pod has an init container that fails. The status shows 'Init:CrashLoopBackOff'. The pod's restartPolicy is 'Always'. What happens to the init container?

Accepted Answer

The init container will restart until it succeeds. Init containers always run to completion before any main containers start, and they are restarted until they succeed regardless of the pod's restartPolicy. The restartPolicy only applies to main containers, not init containers. When an init container fails, Kubernetes restarts it indefinitely until it exits with a zero status, which is why the status shows 'Init:CrashLoopBackOff'.

Answer

The pod will be deleted and recreated

Answer

The main containers will start anyway

Answer

The init container will not restart because the pod's restartPolicy is Always

Question 12

A Job must run 10 times in total, with up to 3 pods running simultaneously. Which fields should be set?

Accepted Answer

completions: 10, parallelism: 3. In a Kubernetes Job, `completions: 10` specifies the total number of successful Pod completions required, and `parallelism: 3` limits the number of Pods that can run concurrently. This ensures the Job runs exactly 10 times with up to 3 Pods in parallel, which matches the requirement.

Answer

completions: 10, successfulJobsHistoryLimit: 3

Answer

completions: 10, parallelism: 10

Answer

completions: 3, parallelism: 10

Question 13

A CronJob is configured with concurrencyPolicy: Forbid and schedule: '*/5 * * * *'. The first job takes 7 minutes. What happens when the next scheduled time arrives?

Accepted Answer

The new job is skipped. C is correct because when `concurrencyPolicy: Forbid` is set, the CronJob controller skips creating a new job if the previous job is still running at the next scheduled time. Since the first job takes 7 minutes and the schedule is every 5 minutes, the new job is skipped to prevent overlapping executions.

Answer

The previous job is terminated

Answer

The new job waits until the previous job completes

Answer

A new job is created immediately

Question 14

You want to expose a container's port 8080 in the Dockerfile. Which instruction should you use?

Accepted Answer

EXPOSE 8080. The `EXPOSE` instruction in a Dockerfile informs Docker that the container listens on the specified network port at runtime. It is a metadata declaration that does not actually publish the port; it serves documentation and inter-container communication purposes via Docker networks.

Answer

PORT 8080

Answer

LISTEN 8080

Answer

PUBLISH 8080

Question 15

Which instruction in a Dockerfile sets the default command to run when the container starts, but allows overriding?

Accepted Answer

CMD. The CMD instruction in a Dockerfile defines the default command to execute when a container starts from the image. It can be overridden by providing a command at the end of the `docker run` command, making it the correct choice for a default command that allows user override.

Answer

START

Answer

RUN

Answer

ENTRYPOINT