CKAD Application Design and Build Practice Test 9 — 15 Questions

Question 1

Which TWO statements about the .dockerignore file are true?

Accepted Answer

It supports pattern matching similar to .gitignore. The .dockerignore file supports pattern matching using glob patterns, similar to .gitignore. This allows you to define patterns to exclude files and directories from the Docker build context, preventing them from being sent to the Docker daemon during a build.

Answer

It is automatically applied to all docker commands

Answer

It can be used to specify which Dockerfile to use

Answer

It can override the base image from the Dockerfile

Question 2

Which THREE of the following are valid patterns for multi-container pods?

Accepted Answer

Ambassador. The Ambassador pattern is a valid multi-container pod pattern where a proxy container handles network communication on behalf of the main application container, abstracting external service connectivity. This pattern is commonly implemented with tools like Envoy or a custom sidecar proxy that manages TLS termination, service discovery, or circuit breaking, allowing the main container to connect to localhost while the ambassador handles remote connections.

Answer

Init

Answer

Daemon

Question 3

You are given a pod YAML that uses an init container to wait for a database. The init container exits with code 0, but the main container crashes. Which TWO fields in the pod spec directly affect the behavior of the main container after it crashes?

Accepted Answer

spec.restartPolicy. `spec.restartPolicy` is the field that directly controls what happens after a container crashes; it determines whether the container is restarted (Always, OnFailure, or Never). `spec.containers[0].livenessProbe` does not affect behavior after a crash because liveness probes check the health of a running container, not the container's exit status. After a crash, the kubelet restarts the container based solely on restartPolicy.

Answer

spec.containers[0].readinessProbe

Answer

spec.initContainers[0].restartPolicy

Answer

spec.containers[0].command

Answer

spec.containers[0].livenessProbe

Question 4

Which of the following Dockerfile instructions sets the working directory for any subsequent RUN, CMD, ENTRYPOINT, COPY, and ADD instructions?

Accepted Answer

WORKDIR. The WORKDIR instruction sets the working directory for any subsequent RUN, CMD, ENTRYPOINT, COPY, and ADD instructions in the Dockerfile. If the directory does not exist, it will be created automatically, and it persists across all subsequent instructions until changed by another WORKDIR.

Answer

EXPOSE

Answer

COPY

Answer

USER

Question 5

Which of the following commands creates a deployment named 'webapp' that runs the image 'nginx:1.25' with 3 replicas?

Accepted Answer

kubectl create deployment webapp --image=nginx:1.25 --replicas=3. The correct command to create a Deployment named 'webapp' with the nginx:1.25 image and 3 replicas is 'kubectl create deployment webapp --image=nginx:1.25 --replicas=3'. Option B uses 'kubectl run', which creates a Pod, not a Deployment, and does not support the --replicas flag in modern Kubernetes. Option C is missing the --replicas flag, so it creates a Deployment with only the default of 1 replica. Option D uses 'kubectl expose', which creates a Service, not a Deployment.

Answer

kubectl run webapp --image=nginx:1.25 --replicas=3

Answer

kubectl create deployment webapp --image=nginx:1.25

Answer

kubectl expose deployment webapp --port=80

Question 6

You have a multi-container pod with a main container and a sidecar container that collects logs. The sidecar container should start before the main container and must complete initialization tasks before the main container starts. Which type of container should you use for this purpose?

Accepted Answer

Init container. Init containers run to completion before any regular containers in the pod start, making them ideal for prerequisites like initialization tasks or log setup. In this scenario, the sidecar must complete its initialization before the main container begins, which is exactly the behavior of an init container. Regular sidecar containers run concurrently with the main container, not before it.

Answer

Ephemeral container

Answer

Job

Answer

Regular sidecar container

Question 7

You have a pod that runs a single container with the following resource limits: memory: 256Mi, cpu: 500m. The container is consistently using 300Mi of memory and 300m of CPU. The pod is running but you want to avoid OOMKilled. Which change should you make?

Accepted Answer

Increase memory limit to 512Mi. The container is consistently using 300Mi of memory, which exceeds the current memory limit of 256Mi. When a container exceeds its memory limit, the kernel's OOM killer terminates the process (OOMKilled). Increasing the limit to 512Mi provides headroom above the actual usage, preventing OOM kills while allowing the container to continue running.

Answer

Set memory request to 128Mi and keep limit at 256Mi

Answer

Decrease memory limit to 128Mi

Answer

Increase CPU limit to 1000m

Question 8

Which of the following is the correct apiVersion for a Kubernetes Job in v1.29?

Accepted Answer

batch/v1. In Kubernetes v1.29, the correct apiVersion for a Job is `batch/v1`. The `batch/v1` API version has been stable since Kubernetes 1.21, and Jobs are part of the batch API group. Using `batch/v1` ensures compatibility with the current stable release and provides access to all Job features, including parallelism, completions, and backoff limits.

Answer

apps/v1

Answer

v1

Answer

batch/v1beta1

Question 9

You need to add a debugging container to a running pod named 'app-pod' in the 'dev' namespace. Which command achieves this?

Accepted Answer

kubectl debug pod/app-pod -n dev --image=busybox --ephemeral. `kubectl debug` with the `--ephemeral` flag creates an ephemeral container in the running pod, which is the standard Kubernetes mechanism for adding a debugging container to an existing pod without restarting it. The `--image=busybox` specifies the debugging image, and `-n dev` targets the correct namespace.

Answer

kubectl run debug-pod --image=busybox -n dev --rm -it

Answer

kubectl attach pod/app-pod -n dev

Answer

kubectl exec pod/app-pod -n dev -it -- /bin/sh

Question 10

In a Kubernetes pod definition, which field specifies the container image to use?

Accepted Answer

containers.image. In a Kubernetes pod definition, the container image is specified under the `containers` array within the pod spec. Each container in the array has an `image` field that defines the container image to use (e.g., `nginx:1.25`). Option A correctly uses the dot notation `containers.image` to reference this field, which is the standard way to access the image property of a container in a pod manifest.

Answer

spec.image

Answer

containers.name

Answer

spec.containers.image

Question 11

Which TWO statements about init containers are true?

Accepted Answer

Init containers run to completion before any regular containers start.. Init containers are designed to run to completion before any regular containers in the Pod start. This ensures that prerequisites (e.g., database schema migrations, configuration file generation, or waiting for a service to become available) are satisfied before the main application containers begin execution.

Answer

Init containers run in parallel with regular containers.

Answer

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

Answer

Init containers cannot access volumes shared with regular containers.

Question 12

Which TWO commands can be used to create a resource from a YAML file?

Accepted Answer

kubectl create -f pod.yaml. The `kubectl create -f pod.yaml` command is correct because it instructs Kubernetes to create a resource (in this case, a Pod) defined in the specified YAML file. This is a declarative command that submits the resource manifest to the API server, which validates and stores it in etcd, resulting in the resource being created in the cluster.

Answer

kubectl delete -f pod.yaml

Answer

kubectl get -f pod.yaml

Answer

kubectl run -f pod.yaml

Question 13

Which THREE statements about Dockerfile CMD and ENTRYPOINT are correct?

Accepted Answer

CMD can be overridden at container runtime by specifying a command after the image name.. Only three statements are correct. Option A is false because CMD is not ignored when ENTRYPOINT is defined; CMD provides default arguments to ENTRYPOINT. Option B is correct: specifying a command after the image name at runtime overrides CMD. Option C is correct: ENTRYPOINT can be overridden with `--entrypoint` flag. Option D is correct: CMD provides default arguments to ENTRYPOINT when both are present. Option E is incorrect because if neither CMD nor ENTRYPOINT is specified, the container inherits the base image's default command, which may keep it running (e.g., a shell) or cause it to exit; it does not always run and exit immediately.

Answer

CMD is always ignored if ENTRYPOINT is defined.

Answer

If neither CMD nor ENTRYPOINT is specified, the container will run but exit immediately.

Question 14

You are tasked with building a container image for a Node.js application. The Dockerfile must first install system dependencies, then copy application code, and finally run the app. Which of the following Dockerfiles is correct?

Accepted Answer

FROM node:14
RUN apt-get update && apt-get install -y build-essential
COPY . /app
CMD ["node","app.js"]. It follows the required order: first installs system dependencies using RUN (which executes at build time), then copies application code with COPY, and finally uses CMD to define the default command that runs the Node.js app at container runtime. CMD is the appropriate instruction for specifying the executable when the container starts, as opposed to RUN which would execute during image build and fail to run the app.

Answer

FROM node:14
CMD apt-get update && apt-get install -y build-essential
COPY . /app
CMD ["node","app.js"]

Answer

FROM node:14
RUN apt-get update && apt-get install -y build-essential
COPY . /app
RUN ["node","app.js"]

Answer

FROM node:14
RUN apt-get update && apt-get install -y build-essential
COPY . /app
ENTRYPOINT ["node","app.js"]

Question 15

Which command is used to create a CronJob in Kubernetes that runs a job every 5 minutes?

Accepted Answer

kubectl run cronjob --image=busybox --schedule="*/5 * * * *" -- /bin/sh -c 'date'. Both `kubectl run cronjob --image=busybox --schedule="*/5 * * * *" -- /bin/sh -c 'date'` and `kubectl create cronjob hello --image=busybox --schedule="*/5 * * * *" -- /bin/sh -c 'date'` create a CronJob that runs every 5 minutes. The question should accept both, or be rephrased to indicate the explicit imperative command.

Answer

kubectl apply -f cronjob.yaml

Answer

kubectl create job hello --image=busybox --schedule="*/5 * * * *" -- /bin/sh -c 'date'