Pass the Linux Foundation Kubernetes Administrator CKA Questions and answers with ValidTests

solution

Persistent Volume

A persistent volume is a piece of storage in a Kubernetes cluster. PersistentVolumes are a cluster-level resource like nodes, which don’t belong to any namespace. It is provisioned by the administrator and has a particular file size. This way, a developer deploying their app on Kubernetes need not know the underlying infrastructure. When the developer needs a certain amount of persistent storage for their application, the system administrator configures the cluster so that they consume the PersistentVolume provisioned in an easy way.

Creating Persistent Volume

kind: PersistentVolume

apiVersion: v1

metadata:

name:app-data

spec:

capacity: # defines the capacity of PV we are creating

storage: 2Gi #the amount of storage we are tying to claim

accessModes: # defines the rights of the volume we are creating

- ReadWriteMany

hostPath:

path: "/srv/app-data" # path to which we are creating the volume

Challenge

Create a Persistent Volume named app-data, with access mode ReadWriteMany, storage classname shared, 2Gi of storage capacity and the host path /srv/app-data.

2. Save the file and create the persistent volume.

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3. View the persistent volume.

Our persistent volume status is available meaning it is available and it has not been mounted yet. This status will change when we mount the persistentVolume to a persistentVolumeClaim.

PersistentVolumeClaim

In a real ecosystem, a system admin will create the PersistentVolume then a developer will create a PersistentVolumeClaim which will be referenced in a pod. A PersistentVolumeClaim is created by specifying the minimum size and the access mode they require from the persistentVolume.

Challenge

Create a Persistent Volume Claim that requests the Persistent Volume we had created above. The claim should request 2Gi. Ensure that the Persistent Volume Claim has the same storageClassName as the persistentVolume you had previously created.

kind: PersistentVolume

apiVersion: v1

metadata:

name:app-data

spec:

accessModes:

- ReadWriteMany

resources:

requests:

storage: 2Gi

storageClassName: shared

2. Save and create the pvc

njerry191@cloudshell:~ (extreme-clone-2654111)$ kubect1 create -f app-data.yaml

persistentvolumeclaim/app-data created

3. View the pvc

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4. Let’s see what has changed in the pv we had initially created.

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Our status has now changed from available to bound.

5. Create a new pod named myapp with image nginx that will be used to Mount the Persistent Volume Claim with the path /var/app/config.

Mounting a Claim

apiVersion: v1

kind: Pod

metadata:

creationTimestamp: null

name: app-data

spec:

volumes:

- name:congigpvc

persistenVolumeClaim:

claimName: app-data

containers:

- image: nginx

name: app

volumeMounts:

- mountPath: "/srv/app-data "

name: configpvc

Solution:

kubectl get deployment

kubectl scale deployment.apps/presentation --replicas=6

Task Summary

SSH into cka000060

Add the Argo CD Helm repo named argo

Generate a manifest (~/argo-helm.yaml) for Argo CD version 7.7.3

Target namespace: argocd

Do not install CRDs

Just generate, don’t install

✅ Step-by-Step Solution

1️⃣ SSH into the correct host

ssh cka000060

⚠️ Required — skipping this = zero score

2️⃣ Add the Argo CD Helm repository

helm repo add argo https://argoproj.github.io/argo-helm

helm repo update

✅ This adds the official Argo Helm chart source.

3️⃣ Generate Argo CD Helm chart template (version 7.7.3)

Use the helm template command to generate a manifest and write it to ~/argo-helm.yaml.

helm template argocd argo/argo-cd \

--version 7.7.3 \

--namespace argocd \

--set crds.install=false \

> ~/argo-helm.yaml

argocd → Release name (can be anything; here it's same as the namespace)

--set crds.install=false → Disables CRD installation

> ~/argo-helm.yaml → Save to required file

✅ 4️⃣ Verify the generated file (optional but smart)

head ~/argo-helm.yaml

Check that it contains valid Kubernetes YAML and does not include CRDs.

???? Final Command Summary

ssh cka000060

helm repo add argo https://argoproj.github.io/argo-helm

helm repo update

helm template argocd argo/argo-cd \

--version 7.7.3 \

--namespace argocd \

--set crds.install=false \

> ~/argo-helm.yaml

head ~/argo-helm.yaml # Optional verification

Task Summary

SSH into the correct node: cka000037

Modify existing deployment synergy-leverager

Add a sidecar container:

Name: sidecar

Image: busybox:stable

Command:

/bin/sh -c "tail -n+1 -f /var/log/synergy-leverager.log"

Use a shared volume mounted at /var/log

Don't touch existing container config except adding volume mount

Step-by-Step Solution

1️⃣ SSH into the correct node

ssh cka000037

⚠️ Skipping this will result in a zero score.

2️⃣ Edit the deployment

kubectl edit deployment synergy-leverager

This opens the deployment YAML in your default editor (vi or similar).

3️⃣ Modify the spec as follows

???? Inside the spec.template.spec, do these 3 things:

✅ A. Define a shared volume

Add under volumes: (at the same level as containers):

volumes:

- name: log-volume

emptyDir: {}

✅ B. Add volume mount to the existing container

Locate the existing container under containers: and add this:

volumeMounts:

- name: log-volume

mountPath: /var/log

???? Do not change any other configuration for this container.

✅ C. Add the sidecar container

Still inside containers:, add the new container definition after the first one:

- name: sidecar

image: busybox:stable

command:

- /bin/sh

- -c

- "tail -n+1 -f /var/log/synergy-leverager.log"

volumeMounts:

- name: log-volume

mountPath: /var/log

spec:

containers:

- name: main-container

image: your-existing-image

volumeMounts:

- name: log-volume

mountPath: /var/log

- name: sidecar

image: busybox:stable

command:

- /bin/sh

- -c

- "tail -n+1 -f /var/log/synergy-leverager.log"

volumeMounts:

- name: log-volume

mountPath: /var/log

volumes:

- name: log-volume

emptyDir: {}

Save and exit

If using vi or vim, type:

bash

CopyEdit

wq

5️⃣ Verify

Check the updated pods:

kubectl get pods -l app=synergy-leverager

Pick a pod name and describe it:

kubectl describe pod

Confirm:

2 containers running (main-container + sidecar)

Volume mounted at /var/log

ssh cka000037

kubectl edit deployment synergy-leverager

# Modify as explained above

kubectl get pods -l app=synergy-leverager

kubectl describe pod

Solution:

sudo -i

systemctl status kubelet

systemctl start kubelet

systemctl enable kubelet

kubect1 get po nginx-dev -o

jsonpath='{.spec.containers[].image}{"\n"}'

Task Summary

SSH into cka000022 ✅

Modify an existing Deployment:

Namespace: spline-reticulator

Deployment: front-end

Container: nginx

Expose: port 80/tcp

Create a Service:

Name: front-end-svc

Type: NodePort

Port: 80 → container port 80

✅ Step-by-Step Solution

1️⃣ SSH into the correct node

ssh cka000022

⚠️ Skipping this = zero score

2️⃣ Edit the Deployment to expose port 80

kubectl edit deployment front-end -n spline-reticulator

Under containers: → nginx, add this if not present:

ports:

- containerPort: 80

protocol: TCP

✅ This enables the container to accept traffic on port 80.

3️⃣ Create a NodePort Service

Create a file named front-end-svc.yaml:

cat < front-end-svc.yaml

apiVersion: v1

kind: Service

metadata:

name: front-end-svc

namespace: spline-reticulator

spec:

type: NodePort

selector:

app: front-end

ports:

- port: 80

targetPort: 80

protocol: TCP

EOF

⚠️ Make sure the Deployment has a matching label selector like app: front-end. You can verify with:

kubectl get deployment front-end -n spline-reticulator -o yaml | grep labels -A 2

4️⃣ Apply the service

kubectl apply -f front-end-svc.yaml

5️⃣ Verify

Check if the service is created and has a NodePort assigned:

kubectl get svc front-end-svc -n spline-reticulator

✅ You should see something like:

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

front-end-svc NodePort 10.96.0.123 80:3XXXX/TCP 10s

Where 3XXXX is your automatically assigned NodePort (between 30000–32767).

Final Command Summary

ssh cka000022

kubectl edit deployment front-end -n spline-reticulator

# Add:

# ports:

# - containerPort: 80

cat < front-end-svc.yaml

apiVersion: v1

kind: Service

metadata:

name: front-end-svc

namespace: spline-reticulator

spec:

type: NodePort

selector:

app: front-end

ports:

- port: 80

targetPort: 80

protocol: TCP

EOF

kubectl apply -f front-end-svc.yaml

kubectl get svc front-end-svc -n spline-reticulator

kubectl get po -o=custom-columns="POD_NAME:.metadata.name,

POD_STATUS:.status.containerStatuses[].state"

kubectl get pods -o=jsonpath="{.items[*]['metadata.name',

'metadata.namespace']}"

kubectl get po –all-namespaces > /opt/pods-list.yaml