CKAD Application Design and Build Practice Test 7 — 15 Questions

Question 1

Which of the following Dockerfile instructions is used to set a command that runs when the container starts and can be overridden by command-line arguments?

Accepted Answer

CMD. The CMD instruction in a Dockerfile provides default command(s) for the executing container. When a user runs `docker run image [COMMAND]`, the provided COMMAND overrides the CMD value, making it the correct choice for a command that can be overridden by command-line arguments.

Answer

EXPOSE

Answer

COPY

Answer

RUN

Question 2

Which TWO of the following are valid fields in a Job spec? (Select TWO.)

Accepted Answer

backoffLimit. Options B (backoffLimit) and E (parallelism) are correct fields in a Job spec. 'backoffLimit' controls the number of retries before marking the Job as failed, and 'parallelism' specifies the maximum number of Pods running in parallel. Option A (replicas) is a field for Deployments, not Jobs. Option C (schedule) is used in CronJobs. Option D (restartPolicy) is a Pod-level field; in Jobs, the restartPolicy is defaulted to OnFailure or Never but is not a top-level Job spec field.

Answer

replicas

Answer

schedule

Answer

restartPolicy

Question 3

Which THREE of the following are correct about init containers? (Select THREE.)

Accepted Answer

They run to completion before the main application containers start. Init containers are designed to run sequentially to completion before any of the pod's regular application containers start. This ensures that prerequisites, such as database schema migrations or configuration file generation, are completed before the main application begins execution.

Answer

They cannot have resource limits set

Answer

They run after the main application containers have started

Question 4

Which of the following are valid concurrencyPolicy values for a CronJob? (Select all that apply.)

Accepted Answer

Replace. Within a Kubernetes CronJob, the concurrencyPolicy field accepts three valid values: Allow, Forbid, and Replace. Allow permits multiple concurrent executions of the same job. Forbid prevents new executions while a previous one is still running. Replace cancels the currently running job and starts a new one in its place. Options C (Parallel) and E (Serial) are not valid values. Therefore, the correct answers are Replace, Allow, and Forbid.

Answer

Parallel

Answer

Serial

Question 5

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

Accepted Answer

FROM. The FROM instruction initializes a new build stage and sets the base image for subsequent instructions. In Docker, every Dockerfile must start with a FROM (or ARG before FROM) to specify an existing image, such as `FROM ubuntu:22.04` or `FROM alpine:3.18`, from which the new image is built. Without FROM, the build has no foundation and will fail.

Answer

COPY

Answer

RUN

Answer

CMD

Question 6

You run the following command: 'kubectl run nginx --image=nginx --restart=Never'. What Kubernetes resource is created?

Accepted Answer

Pod. The `kubectl run nginx --image=nginx --restart=Never` command creates a Pod directly, because the `--restart=Never` flag sets the restart policy to Never, which instructs Kubernetes to run the container as a standalone Pod rather than wrapping it in a higher-level controller like a Deployment or Job. The `kubectl run` command, when used without a controller flag, defaults to creating a Pod when `--restart=Never` is specified, as per the Kubernetes API behavior.

Answer

CronJob

Answer

Deployment

Answer

Job

Question 7

You have a multi-stage Dockerfile with two stages: 'builder' and 'runtime'. You want to copy artifacts from the builder stage to the runtime stage. Which Dockerfile instruction achieves this?

Accepted Answer

COPY --from=builder /app/artifact /app/. The COPY instruction with --from=stage-name copies files from a previous build stage.

Answer

EXPORT builder /app/artifact /app/

Answer

ADD --from=builder /app/artifact /app/

Answer

COPY ../builder/artifact /app/

Question 8

A pod has two containers: a web server and a sidecar that scrapes logs. The sidecar container needs to read log files written by the web server. How should the logs be shared between the containers?

Accepted Answer

Use a shared emptyDir volume mounted into both containers at the same path. An emptyDir volume is a shared, ephemeral volume that is created when a Pod is assigned to a node and exists as long as that Pod is running. Both containers in the same Pod can mount the same emptyDir volume at the same or different paths, allowing the sidecar to read log files written by the web server without any external storage dependency. This is the standard Kubernetes pattern for inter-container log sharing within a Pod.

Answer

Use a ConfigMap to store logs

Answer

Use a hostPath volume mounted in both containers

Answer

Use a PersistentVolumeClaim

Question 9

You need to run a one-time batch job that processes 10 work items in parallel, with a maximum of 3 pods running at the same time. Which Job YAML fields should you set?

Accepted Answer

spec.parallelism: 3 and spec.completions: 10. `spec.parallelism: 3` limits the maximum number of pods running concurrently, and `spec.completions: 10` ensures the Job runs 10 work items to completion. This combination processes all 10 items in parallel batches of 3, meeting the requirement of a one-time batch job with a maximum of 3 pods at a time.

Answer

spec.template.spec.containers and spec.completions

Answer

spec.parallelism: 10 and spec.completions: 3

Answer

spec.backoffLimit: 3 and spec.completions: 10

Question 10

You have a CronJob that runs every 5 minutes. The job sometimes takes longer than 5 minutes to complete. You want to ensure that while a job is running, the next scheduled job is skipped (not started). Which concurrencyPolicy should you use?

Accepted Answer

Forbid. The `Forbid` concurrencyPolicy ensures that if a previous job instance is still running when the next scheduled time arrives, the new job is simply skipped (not created). This prevents overlapping executions, which is exactly what you need when a CronJob's duration can exceed its schedule interval.

Answer

Skip

Answer

Allow

Answer

Replace

Question 11

Which of the following best describes the purpose of an init container?

Accepted Answer

Init containers run to completion before the main containers start, and are used for setup tasks. Init containers are specialized containers that run and complete to exit before any pod's main containers start. They are ideal for performing setup tasks such as waiting for a service to be ready, populating configuration files, or running database migrations. This ensures the main application containers start in a fully prepared environment.

Answer

Init containers run in parallel with the main containers to provide auxiliary functionality

Answer

Init containers share the same lifecycle as the main containers

Answer

Init containers are restarted if they exit with a non-zero exit code

Question 12

You want to create a Deployment that runs 5 replicas of a web application. Which kubectl command should you use?

Accepted Answer

kubectl create deployment webapp --image=nginx --replicas=5. To create a Deployment with 5 replicas using a single imperative command, use `kubectl create deployment webapp --image=nginx --replicas=5`. This command directly creates a Deployment and sets the desired replicas. Option A (`kubectl run`) no longer creates a Deployment by default in current Kubernetes versions (1.18+); it creates a single Pod and does not support the `--replicas` flag. Option B (`kubectl create pod`) does not exist and is incorrect. Option C (`kubectl apply -f deployment.yaml`) would also create a Deployment but requires an existing YAML file and is not a single imperative command.

Answer

kubectl run webapp --image=nginx --replicas=5

Answer

kubectl create pod webapp --image=nginx --replicas=5

Answer

kubectl apply -f deployment.yaml

Question 13

You have a Job that should retry up to 3 times if it fails, and should be considered failed after 4 failures total (including retries). Which YAML fields should you set?

Accepted Answer

spec.backoffLimit: 3. The `spec.backoffLimit` field in a Kubernetes Job defines the number of retries before considering the Job as failed. Setting it to 3 means the Job will retry up to 3 times after the initial failure, resulting in a total of 4 failures (1 initial + 3 retries), which matches the requirement.

Answer

spec.activeDeadlineSeconds: 4

Answer

spec.backoffLimit: 4

Answer

spec.restartPolicy: OnFailure and spec.backoffLimit: 3

Question 14

Which of the following is true about the CMD instruction in a Dockerfile?

Accepted Answer

CMD provides a default command that can be overridden at runtime. The CMD instruction in a Dockerfile provides default arguments for the container's main process, which can be overridden when the container is started with a command-line argument (e.g., `docker run `). It is not executed during the image build (that's RUN), it does not expose ports (that's EXPOSE), and it can be used with ENTRYPOINT to supply default parameters that are overridable.

Answer

CMD is always executed during the image build process

Answer

CMD is used to expose ports

Answer

CMD cannot be used in conjunction with ENTRYPOINT

Question 15

You want to debug a running pod by starting a temporary container that has network access to the pod's containers. Which kubectl command should you use?

Accepted Answer

kubectl debug -it --image=debian --target=. `kubectl debug` creates an ephemeral container in the same pod, sharing the pod's network namespace (including localhost and the same IP address) with the target container. The `--target` flag specifies which existing container's namespaces (network, PID, etc.) the ephemeral container should join, enabling direct network debugging of that container without modifying its process.

Answer

kubectl attach <pod>

Answer

kubectl run debug --image=debian --restart=Never

Answer

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