Linux Foundation CKAD Practice Exam Questions & Answers

Solution:

To allow a pod to send and receive traffic only to and from specific pods, you can use network policies in Kubernetes.

First, you will need to create a network policy that defines the allowed traffic. You can create a network policy yaml file with the following rules:

apiVersion: networking.k8s.io/v1

kind: NetworkPolicy

metadata:

name: newpod-network-policy

namespace: default

spec:

podSelector:

matchLabels:

app: kdsn00201-newpod

ingress:

- from:

- podSelector:

matchLabels:

app: web

- podSelector:

matchLabels:

app: storage

This policy will only allow incoming traffic to the pod with the label app=kdsn00201-newpod from pods with the label app=web or app=storage. If you have different labels on your web and storage pods please update the matchLabels accordingly.

Once you have created the network policy, you can apply it to the cluster by running the following command:

kubectl apply -f <network-policy-file>.yaml

This will apply the network policy to the cluster, and the newpod will only be able to send and receive traffic to and from the web and storage pods.

Please note that, NetworkPolicy resource is not available by default, you need to enable the NetworkPolicy feature on your Kubernetes cluster. This feature is enabled by default on some clusters and must be explicitly enabled on others. You can check if NetworkPolicy is available by running the command kubectl api-versions | grep networking

Also, you need to ensure that the pods that you want to allow traffic to and from are running on the same namespace.

Solution:

Solution:

Solution:

ssh ckad00034c

You're debugging an Ingress Service Deployment chain. The fastest way is:

reproduce the error with the right Host header

check Ingress rules (host/path/backend)

check Service (selector/port/targetPort)

check Endpoints (do we have ready pods?)

fix the manifest(s) under /home/candidate/content-marlin/

apply + re-test

Below are the exact commands + the most common fixes for this exact symptom.

1) Reproduce the failing request correctly

Even if DNS isn't set up, you can test with a Host header:

curl -i -H 'Host: content-marlin.local' http://127.0.0.1/content-marlin

If your ingress controller is not on localhost, find the NodePort/LoadBalancer IP. In these labs it's often localhost via a local proxy, but if needed:

kubectl get svc -A | egrep -i 'ingress|nginx'

kubectl get nodes -o wide

(But start with the localhost curl above.)

2) Inspect the provided manifests (this is what you must edit)

cd /home/candidate/content-marlin/

ls -l

sed -n '1,200p' *.yaml

Also view what's currently live in the cluster:

kubectl -n content-marlin get deploy,svc,ingress

kubectl -n content-marlin describe ingress content-marlin-ingress

kubectl -n content-marlin get ingress content-marlin-ingress -o yaml

What to look for in the Ingress:

spec.rules.host should be content-marlin.local

spec.rules.http.paths[].path should match /content-marlin

Backend service name must be your service

Backend service port must match the service port (name or number)

pathType should be Prefix (usually safest)

3) Validate Service Pod wiring (most common real cause)

3.1 Check service selector and ports

kubectl -n content-marlin get svc -o wide

kubectl -n content-marlin describe svc content-marlin-deployment 2>/dev/null || true

kubectl -n content-marlin describe svc

Identify the service that the Ingress points to (from describe ingress).

Check if the Service selector matches pod labels:

kubectl -n content-marlin get pods --show-labels

kubectl -n content-marlin get svc <SERVICE_NAME> -o jsonpath='{.spec.selector}{'\n'}'

3.2 Check endpoints (this tells you instantly if traffic can reach pods)

kubectl -n content-marlin get endpoints

kubectl -n content-marlin get endpoints <SERVICE_NAME> -o wide

If ENDPOINTS is empty Service selector doesn't match Pods OR Pods aren't Ready.

3.3 If endpoints empty, check pod readiness and labels

kubectl -n content-marlin get pods -o wide

kubectl -n content-marlin describe pod

4) Apply the most likely fix patterns

Fix pattern A: Ingress path needs rewrite

If your app serves / but you route /content-marlin, you often need rewrite.

Edit content-marlin-ingress manifest (in /home/candidate/content-marlin/) to include:

path: /content-marlin

pathType: Prefix

annotation: rewrite to / (common for nginx ingress)

Example (typical nginx-ingress):

metadata:

annotations:

nginx.ingress.kubernetes.io/rewrite-target: /

spec:

rules:

- host: content-marlin.local

http:

paths:

- path: /content-marlin

pathType: Prefix

backend:

service:

name: <SERVICE_NAME>

port:

number: 80

If your ingress controller is not nginx, rewrite annotation may differ. But in CKAD labs, it's very often nginx.

Fix pattern B: Ingress points to wrong Service port

If the Ingress backend says port 80 but your Service exposes 8080 (or uses a named port), align them:

Either change Ingress backend port.number

Or change Service spec.ports[].port / targetPort

Fix pattern C: Service selector mismatch (endpoints empty)

If pods have label app=content-marlin but service selector is app=content-marlin-deployment (or vice versa), fix the Service selector to match pod labels.

Service should have:

spec:

selector:

app: <label-that-actually-exists-on-pods>

Fix pattern D: Service targetPort wrong

If container listens on 8080 but service targetPort is 80, fix it:

spec:

ports:

- port: 80

targetPort: 8080

5) Apply the corrected manifests

After editing the YAMLs under /home/candidate/content-marlin/:

kubectl apply -f /home/candidate/content-marlin/

Wait for readiness:

kubectl -n content-marlin rollout status deploy content-marlin-deployment

kubectl -n content-marlin get endpoints

kubectl -n content-marlin describe ingress content-marlin-ingress

6) Re-test the URL

curl -i -H 'Host: content-marlin.local' http://127.0.0.1/content-marlin

If you still get errors, also check ingress controller logs/events quickly:

kubectl -n content-marlin get events --sort-by=.lastTimestamp | tail -n 30

kubectl get pods -A | egrep -i 'ingress|nginx'

The fastest way for you to finish in 1 shot

Run these and paste the output (I'll tell you exactly which line to change and what to change it to):

kubectl -n content-marlin describe ingress content-marlin-ingress

kubectl -n content-marlin get svc -o wide

kubectl -n content-marlin get endpoints -o wide

kubectl -n content-marlin get pods --show-labels

sed -n '1,200p' /home/candidate/content-marlin/*.yaml

But even without pasting, if you follow steps 2--4 above, you'll find the broken link (Ingress rule, Service port, selector, or rewrite) and fix it cleanly.

Understood --- I'll redo Question 13 without using any (or similar) icons.

ssh ckad00033

This task is only about building and exporting a container image.

You must not push it, run it, or consume it in any way.

You may use any image builder. Below are clean, correct solutions. Use one of them.

Option A: Using Docker

1) Go to the Dockerfile location

cd /home/candidate/build

ls -l Dockerfile

2) Build the image

Image name: macaque

Tag: 1.2

docker build -t macaque:1.2 .

Verify:

docker images | grep macaque

3) Export the image to a tar file

Docker image format is acceptable.

docker save macaque:1.2 -o /home/candidate/macaque-1.2.tar

Verify the file exists:

ls -lh /home/candidate/macaque-1.2.tar

Do not load or run the image.

Option B: Using Podman (rootless alternative)

1) Build the image

cd /home/candidate/build

podman build -t macaque:1.2 .

Verify:

podman images | grep macaque

2) Export the image

podman save macaque:1.2 -o /home/candidate/macaque-1.2.tar

Verify:

ls -lh /home/candidate/macaque-1.2.tar

Option C: Using Buildah (OCI format)

cd /home/candidate/build

buildah bud -t macaque:1.2 .

buildah push macaque:1.2 oci-archive:/home/candidate/macaque-1.2.tar