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CKA Practice Exam: Part 2

Managing storage is a challenge for most organizations. Kubernetes allows you to create persistent storage so the data is not lost when a pod is moved or deleted. In this portion of the practice exam, you will demonstrate your knowledge of `PersistentVolumes` and `PersistentVolumeClaims` in order to ensure data integrity. This will simulate a question you may see on the Certified Kubernetes Administrator (CKA) exam.

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Path Info

Level

Intermediate

Duration

1h 0m

Published

Mar 31, 2019

Challenge

Create the `PersistentVolumeClaim`.
1. Use the following command to check if there is already a 'web' namespace:
```
kubectl get ns
kubectl get pv
```
1. Use the following command to create a PersistentVolumeClaim work from scratch or use a Kubernetes template file. Search the documentation :
```
vi data-pvc.yaml #copy and paste from docs
```
1. Update the file data-pvc.yaml with the following details:
```
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: data-pvc
  namespace: web
spec:
  storageClassName: local-storage
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 256Mi
```
1. Use the following command to create the PVC:
```
kubectl apply -f data-pvc.yaml
```

Challenge

Create a pod mounting the volume and write data to the volume.

Use the following command to create the YAML for a busybox pod:

kubectl run data-pod --image=busybox:1.28 --restart=Never -o yaml --dry-run -- /bin/sh -c 'sleep 3600' > data-pod.yaml

Use the following command to edit the data-pod.yaml file:

vi data-pod.yaml

Update the data-pod.yaml file as below:

apiVersion: v1
kind: Pod
metadata:
  name: data-pod
  namespace: web
spec:
  containers:
  - args:
    - /bin/sh
    - -c
    - sleep 3600
    image: busybox:1.28
    name: data-pod
    resources: {}
    volumeMounts: 
    - name: temp-data
      mountPath: /tmp/data
  dnsPolicy: ClusterFirst
  restartPolicy: Never
  volumes: 
  - name: temp-data
    persistentVolumeClaim:
      claimName: data-pvc

Use the following command to create the pod:

kubectl apply -f data-pod.yaml

Use the following command to connect to the pod:

kubectl exec -it data-pod -n web -- sh

Use the following commands to confirm the environmant and to copy the contents of the etc/passwd file to /tmp/data:

# ls -la /etc/passwd
# ls -la /tmp/data/
# cp /etc/passwd /tmp/data/passwd

Use the following command to list the contents of /tmp/data:

# ls /tmp/data/

Challenge

Delete the pod and create a new pod and view volume data.
1. Use the following command to delete the pod:
```
kubectl delete po data-pod -n web
```
2. Use the following command to modify the pod YAML:
```
vi data-pod.yaml
```
3. Change the following line in the data-pod.yaml file:
```
name: data-pod2
```
4. Use the following command to create a new pod:
```
kubectl apply -f data-pod.yaml
```
5. Use the following command to connect to the pod and view the contents of the volume:
```
kubectl exec -it data-pod2 -n web -- sh

# ls /tmp/data
```

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

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