CKAD Application Design and Build Practice Test 9 — 15 Questions

Question 1

You are designing a Pod that must run a diagnostic tool to collect network logs before the main application starts. The diagnostic tool should run to completion, then the main application starts. Which approach should you use?

Accepted Answer

Add the diagnostic tool as an init container in the Pod. Option B is correct. Init containers run sequentially to completion before app containers start. Option A is incorrect because sidecars run concurrently with the main container. Option C is incorrect because a Job is a separate resource, not part of the same Pod. Option D is incorrect because the diagnostic tool is not a sidecar.

Answer

Add the diagnostic tool as a sidecar container in the same Pod

Answer

Add the diagnostic tool as a sidecar container with a postStart hook

Answer

Create a separate Job that runs before the Pod

Question 2

Which YAML snippet correctly defines a CronJob that runs a task every 5 minutes?

Accepted Answer

schedule: "*/5 * * * *". Option D is correct. The schedule syntax for every 5 minutes is '*/5 * * * *'. Option A is every minute. Option B is every 5 hours. Option C is not valid.

Answer

schedule: "*/5 * * *"

Answer

schedule: "0 */5 * * *"

Answer

schedule: "* * * * *"

Question 3

You have a CronJob that runs a backup every hour. Due to a network issue, some backups take longer than an hour, causing overlapping executions. You want to ensure that if a new job is scheduled while the previous one is still running, the new job is skipped. Which concurrencyPolicy should you set?

Accepted Answer

ConcurrencyPolicy: Forbid. Option B is correct. Forbid prevents new jobs from starting if the previous job is still running. Option A allows concurrent runs. Option C replaces the running job with the new one. Option D is invalid.

Answer

ConcurrencyPolicy: Skip

Answer

ConcurrencyPolicy: Allow

Answer

ConcurrencyPolicy: Replace

Question 4

A developer wants to debug a running container in a Pod named 'web-app' in namespace 'dev'. Which command attaches an ephemeral container with the 'nicolaka/netshoot' image for network debugging?

Accepted Answer

kubectl debug web-app -n dev --image=nicolaka/netshoot -c debugger. Option C is correct. kubectl debug with --image and -c creates an ephemeral container. Option A uses attach which is for existing containers. Option B uses exec into a new container but ephemeral is the correct approach. Option D uses run but does not target the pod.

Answer

kubectl run debugger -n dev --image=nicolaka/netshoot --restart=Never

Answer

kubectl attach web-app -n dev -c debugger --image=nicolaka/netshoot

Answer

kubectl exec -n dev web-app --image=nicolaka/netshoot -- /bin/bash

Question 5

What is the purpose of a .dockerignore file in a Docker build context?

Accepted Answer

It excludes files and directories from being sent to the Docker daemon during the build. Option C is correct. .dockerignore excludes files and directories from the build context, making builds faster and more secure. Option A is about ordering layers. Option B is about security scanning. Option D is not a standard behavior.

Answer

It limits the number of layers in the final image

Answer

It defines environment variables for the container

Answer

It specifies the order of layers in the Docker image

Question 6

You are deploying a Pod that contains two containers: a web server and a file sync agent. The file sync agent needs to run as long as the web server is running and should share the same network namespace. Which design pattern does this represent?

Accepted Answer

Sidecar pattern. Option A is correct. A sidecar container runs alongside the main container, sharing the same Pod lifecycle and network namespace. Option B is an adapter pattern for normalizing output. Option C is an ambassador pattern for proxying. Option D is not a standard pattern.

Answer

Adapter pattern

Answer

Ambassador pattern

Answer

Init container pattern

Question 7

You need to run a batch job that processes 10 items in parallel across 10 Pods, but the job should be considered complete only when all 10 Pods have succeeded. Which Job configuration is correct?

Accepted Answer

spec: completions: 10; parallelism: 10. Option B is correct. completions: 10 and parallelism: 10 will run 10 Pods in parallel and require all 10 to succeed. Option A has completions: 10 but parallelism: 1, so Pods run sequentially. Option C has completions: 1, so only one Pod needs to succeed. Option D has parallelism: 10 but completions: 1, so only one Pod needs to succeed.

Answer

spec: completions: 10; parallelism: 1

Answer

spec: completions: 1; parallelism: 10

Answer

spec: completions: 10; parallelism: 0

Question 8

You are writing a Dockerfile and want to ensure that the CMD instruction is overridable when running the container, but the ENTRYPOINT should not be easily overridden. Which combination should you use?

Accepted Answer

ENTRYPOINT ["myapp"]. Option D is correct. ENTRYPOINT sets the executable that cannot be overridden (unless --entrypoint flag is used). CMD provides default arguments that can be overridden by command line arguments. Option A uses ENTRYPOINT with exec form which is overridable via --entrypoint. Option B uses both as CMD, which is fully overridable. Option C uses ENTRYPOINT with shell form, which is also overridable.

Answer

ENTRYPOINT ["myapp"]; CMD ["--help"]

Answer

CMD ["myapp", "--help"]

Answer

ENTRYPOINT myapp; CMD --help

Question 9

You have a Deployment with 3 replicas. You need to perform a rolling update with a 10-second delay between each Pod replacement to ensure stability. Which kubectl command is correct?

Accepted Answer

kubectl set image deployment/myapp myapp=myapp:v2 --record. Option A is correct. kubectl set image updates the image, and the --record flag is outdated but acceptable. Option B uses edit which is not needed. Option C uses rollout restart which does not change the image. Option D applies a patch but is more complex.

Answer

kubectl rollout restart deployment/myapp

Answer

kubectl edit deployment/myapp and change the image manually

Answer

kubectl patch deployment/myapp -p '{"spec":{"template":{"spec":{"containers":[{"name":"myapp","image":"myapp:v2"}]}}}}'

Question 10

Which TWO statements about init containers are true?

Accepted Answer

Init containers can have resource limits different from app containers.. Options A and D are correct. Init containers must run to completion before app containers start (A). They can have different resource limits than app containers (D) and can use different container images. Option B is false because init containers run sequentially, not in parallel. Option C is false because init containers can have their own images. Option E is false because init containers run before all app containers.

Answer

Init containers can run in parallel with each other.

Answer

Init containers are restarted if they fail, using the same restart policy as the app containers.

Answer

Init containers must use the same container image as the app containers.

Question 11

Which TWO options are valid ways to tag an image when building with Docker?

Accepted Answer

docker tag myapp:1.0 myrepo/myapp:1.0. Options A and B are correct. docker build -t myapp:1.0 . tags the image during build. docker tag myapp:1.0 myrepo/myapp:1.0 adds an additional tag. Option C is invalid because --tag is the correct flag, not --name. Option D is invalid because docker commit requires a container ID, not an image name. Option E is invalid because docker run does not tag.

Answer

docker build --name myapp:1.0 .

Answer

docker commit myapp:1.0 myrepo/myapp:1.0

Answer

docker run -t myapp:1.0 myrepo/myapp:1.0

Question 12

Which THREE are valid patterns for multi-container Pods?

Accepted Answer

Ambassador. Options A, B, and C are correct: sidecar (adds helper container), adapter (normalizes output), and ambassador (proxies external access). Option D (replicator) is not a standard pattern. Option E (init) is a special container type, not a pattern for multi-container design.

Answer

Init

Answer

Replicator

Question 13

Which Dockerfile instruction sets a command that can be overridden when running the container?

Accepted Answer

CMD. The CMD instruction provides defaults for executing the container; it can be overridden by command-line arguments. ENTRYPOINT, on the other hand, defines the executable that will always run.

Answer

RUN

Answer

EXPOSE

Answer

ENTRYPOINT

Question 14

What is the primary purpose of an init container in a pod?

Accepted Answer

To perform initialization tasks such as waiting for a database to be ready. Init containers run to completion before the main containers start, typically used for setup tasks like waiting for a service or preparing data.

Answer

To provide a debugging shell into the pod

Answer

To handle traffic routing between services

Answer

To run a long-running process alongside the main container

Question 15

A developer runs 'kubectl run mypod --image=nginx --restart=Never' and the pod is created. However, when the container exits, the pod terminates. Which restart policy ensures the pod does NOT restart after completion?

Accepted Answer

Never. The '--restart=Never' flag sets the restart policy to 'Never', meaning the pod will not be restarted after the container exits.

Answer

Always

Answer

OnFailure

Answer

AlwaysFail