What are Persistent Volumes in k8s?

In Kubernetes, a Persistent Volume (PV) is a piece of storage in the cluster that has been provisioned by an administrator. A Persistent Volume Claim (PVC) is a request for storage by a user. The PVC references the PV, and the PV is bound to a specific node.

How to create a PV?

Add a Persistent Volume to your Deployment todo app.

• Create a Persistent Volume using a file on your node.

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv-todo-app
    spec:
      capacity:
        storage: 1Gi
      accessModes:
        - ReadWriteOnce
      persistentVolumeReclaimPolicy: Retain
      hostPath:
        path: "/tmp/data"
  

• Create a Persistent Volume Claim that references the Persistent Volume.

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      name: pvc-todo-app
    spec:
      accessModes:
        - ReadWriteOnce
      resources:
        requests:
          storage: 500Mi
  

• Update your deployment.yml file to include the Persistent Volume Claim. After Applying pv.yml pvc.yml deployment file look like this

  

    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: todo-app-deployment
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: todo-app
      template:
        metadata:
          labels:
            app: todo-app
        spec:
          containers:
            - name: todo-app
              image: sri766/django-app
              ports:
                - containerPort: 8000
              volumeMounts:
                - name: todo-app-data
                  mountPath: /app
          volumes:
            - name: todo-app-data
              persistentVolumeClaim:
                claimName: pvc-todo-app
  

• Apply the updated deployment using the command: kubectl apply -f deployment.yml

• Verify that the Persistent Volume has been added to your Deployment by checking the status of the Pods and Persistent Volumes in your cluster. Use this commands kubectl get pods ,

  kubectl get pv

  

Happy Learning!!