CKA - kodekloud Practice Test - Lightning Lab

1번

• 현재 1.32 버전으로 업데이트 불가

2번

Print the names of all deployments in the admin2406 namespace in the following format:

DEPLOYMENT   CONTAINER_IMAGE   READY_REPLICAS   NAMESPACE

<deployment name>   <container image used>   <ready replica count>   <Namespace>
. The data should be sorted by the increasing order of the deployment name.


Example:

DEPLOYMENT   CONTAINER_IMAGE   READY_REPLICAS   NAMESPACE
deploy0   nginx:alpine   1   admin2406
Write the result to the file /opt/admin2406_data.

• 정답 : kubectl get deploy -n admin2406 -o custom-columns=DEPLOYMENT:.metadata.name,CONTAINER_IMAGE:.spec.template.spec.containers[0].image,READY_REPLICAS:.status.readyReplicas,NAMESPACE:.metadata.namespace --sort-by=.metadata.name > /opt/admin2406_data
  • 확인 : cat /opt/admin2406_data
  • 참고 docs : https://kubernetes.io/docs/reference/kubectl/

 

3번

A kubeconfig file called admin.kubeconfig has been created in /root/CKA. 
There is something wrong with the configuration. Troubleshoot and fix it.

• 정답
  • vi /root/CKA/admin.kubeconfig
  • controlplane:4380 -> controlplane:6443
  • 참고 docs : https://kubernetes.io/docs/reference/networking/ports-and-protocols/

 

4번

Create a new deployment called nginx-deploy, with image nginx:1.16 and 1 replica.
Next, upgrade the deployment to version 1.17 using rolling update and add the annotation message
Updated nginx image to 1.17

• deploy 생성
  • kubectl create deploy nginx-deploy --image=nginx:1.16 --replicas=1
• upgrade
  • kubectl set image deployment/nginx-deploy nginx=nginx:1.17
  • https://kubernetes.io/docs/reference/kubectl/generated/kubectl_set/kubectl_set_image/
• annotation
  • kubectl annotate deployment nginx-deploy message="Updated nginx image to 1.17"
  • https://kubernetes.io/docs/reference/kubectl/generated/kubectl_annotate/

 

5번

A new deployment called alpha-mysql has been deployed in the alpha namespace.
However, the pods are not running. Troubleshoot and fix the issue.
The deployment should make use of the persistent volume alpha-pv 
to be mounted at /var/lib/mysql and should use the environment 
variable MYSQL_ALLOW_EMPTY_PASSWORD=1 to make use of an empty root password.


Important: Do not alter the persistent volume.

• k get pvc -n alpha로 pvc가 있는지 확인
• k describe pod alpha-mysql-b4fbd744d-zrsk8 -n alpha 후 env, mounts 경로 확인(없다면 pvc 생성 후 작성)
• describe 후, ClaimName과 pvc에서 사용할 metadata.name이 일치해야 하기에 확인

• vi alpha-pvc.yaml
  • metadata.name : deploy에서 확인 후 작성
  • namespace 추가
  • spec.volumeName : alpha-pv 명시
  • 처음엔 spec.resources.requests.storage: 8Gi가 default였고, 이대로 하니

    Cannot bind to requested volume "alpha-pv": requested PV is too small

    와 같은 에러가 발생함.
    • k get pv alpha-pv -o yaml로 확인해 보니 storage가 1Gi 였기에 pvc에서도 1Gi로 변경함
• apiVersion: v1 kind: PersistentVolumeClaim metadata: name: mysql-alpha-pvc namespace: alpha spec: volumeName: alpha-pv accessModes: - ReadWriteOnce volumeMode: Filesystem resources: requests: storage: 1Gi storageClassName: slow selector: matchLabels: release: "stable" matchExpressions: - {key: environment, operator: In, values: [dev]}
• k apply -f alpha-pvc.yaml
• k get pods -n alpha로 제대로 적용 되었는지 확인
• 참고 docs : https://kubernetes.io/docs/concepts/storage/persistent-volumes/

6번

Take the backup of ETCD at the location /opt/etcd-backup.db on the controlplane node.

• cat /etc/kubernetes/manifests/etcd.yaml로 확인(기억 안나면 static pod docs에 경로 있음)
• ETCDCTL_API=3 etcdctl --endpoints=https://127.0.0.1:2379 \
  --cacert=/etc/kubernetes/pki/etcd/ca.crt \
  --cert=/etc/kubernetes/pki/etcd/server.crt \
  --key=/etc/kubernetes/pki/etcd/server.key \
  snapshot save /opt/etcd-backup.db
• 참고 docs
  • https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/
  • https://kubernetes.io/docs/tasks/configure-pod-container/static-pod/

 

7번

Create a pod called secret-1401 in the admin1401 namespace using the busybox image.
The container within the pod should be called secret-admin and should sleep for 4800 seconds.

The container should mount a read-only secret volume called secret-volume at the path /etc/secret-volume. 
The secret being mounted has already been created for you and is called dotfile-secret.

• k run secret-1401 --image=busybox -n admin1401 --dry-run=client -o yaml > secret.yaml
• vi secret.yaml

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: secret-1401
  name: secret-1401
  namespace: admin1401
spec:
  volumes:
  - name: secret-volume
    secret:
      secretName: dotfile-secret
  containers:
  - image: busybox
    volumeMounts:
    - mountPath: /etc/secret-volume
      name: secret-volume
      readOnly: true
    name: secret-admin
    resources: {}
    command: [ "sh", "-c", "sleep 4800" ]
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

• spec.volumes 추가
• spec.containers.volumeMounts 추가(spec.volumes의 name과 volumeMounts의 name은 같아야함)
• spec.containers.command 추가
• 참고 docs
  • https://kubernetes.io/docs/tasks/configure-pod-container/security-context/