State Persistence (8%)
Practice questions based on these concepts
- Understand PersistentVolumeClaims for Storage
Questions
List Persistent Volumes in the cluster
kubectl get pv
Create a hostPath PersistentVolume named task-pv-volume with storage 10Gi, access modes ReadWriteOnce, storageClassName manual, and volume at /mnt/data and verify
// task-pv-volume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: task-pv-volume
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 10Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
kubectl create -f task-pv-volume.yaml
kubectl get pv
Create a PersistentVolumeClaim of at least 3Gi storage and access mode ReadWriteOnce and verify status is Bound
// task-pv-claim.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: task-pv-claim
spec:
storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 3Gi
kubectl create -f task-pv-claim.yaml
kubectl get pvc
Delete persistent volume and PersistentVolumeClaim we just created
kubectl delete pvc task-pv-claim
kubectl delete pv task-pv-volume
Create a Pod with an image Redis and configure a volume that lasts for the lifetime of the Pod
// emptyDir is the volume that lasts for the life of the pod
apiVersion: v1
kind: Pod
metadata:
name: redis
spec:
containers:
- name: redis
image: redis
volumeMounts:
- name: redis-storage
mountPath: /data/redis
volumes:
- name: redis-storage
emptyDir: {}
kubectl create -f redis-storage.yaml
Exec into the above pod and create a file named file.txt with the text ‘This is called the file’ in the path /data/redis and open another tab and exec again with the same pod and verifies file exist in the same path.
// first terminal
kubectl exec -it redis-storage /bin/sh
cd /data/redis
echo 'This is called the file' > file.txt
//open another tab
kubectl exec -it redis-storage /bin/sh
cat /data/redis/file.txt
Delete the above pod and create again from the same yaml file and verifies there is no file.txt in the path /data/redis.
kubectl delete pod redis
kubectl create -f redis-storage.yaml
kubectl exec -it redis-storage /bin/sh
cat /data/redis/file.txt // file doesn't exist
Create PersistentVolume named task-pv-volume with storage 10Gi, access modes ReadWriteOnce, storageClassName manual, and volume at /mnt/data and Create a PersistentVolumeClaim of at least 3Gi storage and access mode ReadWriteOnce and verify status is Bound
kubectl create -f task-pv-volume.yaml
kubectl create -f task-pv-claim.yaml
kubectl get pv
kubectl get pvc
Create an nginx pod with containerPort 80 and with a PersistentVolumeClaim task-pv-claim and has a mouth path "/usr/share/nginx/html"
// task-pv-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: task-pv-pod
spec:
volumes:
- name: task-pv-storage
persistentVolumeClaim:
claimName: task-pv-claim
containers:
- name: task-pv-container
image: nginx
ports:
- containerPort: 80
name: "http-server"
volumeMounts:
- mountPath: "/usr/share/nginx/html"
name: task-pv-storage
kubectl create -f task-pv-pod.yaml
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