Day - 36 : Managing Persistent Volumes in Your Deployment

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.

Task 1:

Add a Persistent Volume to your Deployment todo app.

Create a Persistent Volume using a file on your node.

This is a piece of storage in your cluster that can be dynamically provisioned and claimed by a Pod. To create a Persistent Volume, you can use a file on your node. You can create a YAML file, called pv.yml, that defines the Persistent Volume. This file should include the size of the storage, the access modes, and the path to the file on your node.

• Create a file pv.yaml and write the code for Persistent Volume.

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

kubectl apply -f pv.yaml

• Create a file pvc.yaml and write the code for Persistent Volume Claim.

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

• Create a file deploymentvolumes.yaml and write the code for Deployment.

kubectl apply -f deploymentvolumes.yaml

• Verify that the Persistent Volume has been added to your Deployment by checking the Pods and Persistent Volumes status in your cluster. Use these commands.

Task 2:

• Connect to a Pod in your Deployment using the command :

kubectl exec -it <pod-name> -- /bin/bash

• Here we can create a file in the pod and check the data in the Persistent Volume in the interactive shell.

cd /tmp/app

• At last exit from the pod.

• Verify that you can access the data stored in the Persistent Volume from within the Pod by checking the contents of the file you created in the Pod.