CKAD: Second Mock Challenge

October 9, 2026 - 3 mins read

What is CKAD for?

A certified Kubernetes Application Developer (CKAD) can design, build and deploy cloud-native applications for Kubernetes. He can define application resources and use Kubernetes core primitives to create/migrate, configure, expose and observe scalable applications. CKAD certificate is valid for two years.

Any successful candidate will be comfortable:

working with (OCI-compliant) container images
applying Cloud Native application concepts and architectures – working with and validating Kubernetes resource definitions

I’m currently preparing for my Certified Kubernetes Application Developer (CKAD). This free challenge is from the kodecloud.com.

file-server

Change coredns image

kubectl set image deployment/coredns \
  coredns=registry.k8s.io/coredns/coredns:v1.8.6 -n kube-system

Troubleshoot controlplane

Find the process ID of the kube-apiserver

➜ crictl ps -a | grep kube-apiserver
a0fecb3b907b7       c42f13656d0b2       About a minute ago   Exited              kube-apiserver            8                   f26f52bcb6f08       kube-apiserver-controlplane

➜ crictl logs a0fecb3b907b7
I1009 20:45:09.828623       1 options.go:221] external host was not specified, using 10.244.30.163
I1009 20:45:09.829302       1 server.go:148] Version: v1.30.0
I1009 20:45:09.829338       1 server.go:150] "Golang settings" GOGC="" GOMAXPROCS="" GOTRACEBACK=""
E1009 20:45:10.079433       1 run.go:74] "command failed" err="open /etc/kubernetes/pki/ca-authority.crt: no such file or directory"

The issue here is that ca-authority.crt doesn’t exist. If you check /etc/kubernetes/pki, you should find ca.crt as the correct certificate.

Edit kube-apiserver.yaml

Please backup kube-apiserver.yaml first before modifying the file. kube-apiserver will not start if you made a mistake and your backup is your way to recover.

apiVersion: v1
kind: Pod
metadata:
  annotations:
    kubeadm.kubernetes.io/kube-apiserver.advertise-address.endpoint: 10.244.30.163:6443
  creationTimestamp: null
  labels:
    component: kube-apiserver
    tier: control-plane
  name: kube-apiserver
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-apiserver
    - --advertise-address=10.244.30.163
    - --allow-privileged=true
    - --authorization-mode=Node,RBAC
    - --client-ca-file=/etc/kubernetes/pki/ca.crt

Copy media files

From controlplane, copy files to node01.

➜ scp /media/*.png node01:/web
kodekloud-ckad.png                  100%   58KB  22.9MB/s   00:00    
kodekloud-cka.png                   100%   57KB  41.0MB/s   00:00    
kodekloud-cks.png                   100%   61KB  40.3MB/s   00:00

To check, ssh to node01, then view the files.

➜ ssh node01
Last login: Fri Oct  9 20:51:12 2026 from 10.244.30.163

➜ ls -l /web
total 184
-rw-r--r-- 1 root root 58450 Oct  9 20:53 kodekloud-cka.png
-rw-r--r-- 1 root root 59809 Oct  9 20:53 kodekloud-ckad.png
-rw-r--r-- 1 root root 62223 Oct  9 20:53 kodekloud-cks.png

Persistent volume

apiVersion: v1
kind: PersistentVolume
metadata:
  name: data-pv
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteMany
  hostPath:
    path: /web

Persistent volume claim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: data-pvc
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi
  volumeName: data-pv

Pod with toleration

apiVersion: v1
kind: Pod
metadata:
  name: gop-file-server
  labels:
    app: file-server
spec:
  volumes:
  - name: data-store
    persistentVolumeClaim:
      claimName: data-pvc
  containers:
  - name: gop-file-server 
    image: kodekloud/fileserver
    volumeMounts:
    - name: data-store
      mountPath: /web
  tolerations:
  - key: node-role.kubernetes.io/control-plane
    operator: Exists
    effect: NoSchedule

Service

apiVersion: v1
kind: Service
metadata:
  labels:
    app: file-server
  name: gop-fs-service
spec:
  ports:
  - port: 8080
    protocol: TCP
    targetPort: 8080
  selector:
    app: file-server