Scenario: You're running a simple WordPress website in a Kubernetes cluster. The website consists of a WordPress application and a MySQL database. You need to ensure that the MySQL database data is persistent, so even if the MySQL pod is rescheduled or replaced, the data remains intact.

1. Create a Storage Class:

   • Example: You create a StorageClass called standard-storage for your website's data.

   • YAML Definition:

       apiVersion: storage.k8s.io/v1
       kind: StorageClass
       metadata:
         name: standard-storage
       provisioner: example.com/standard-provisioner
     

   • Explanation: You define a StorageClass to specify the type of storage you want to use for your data.

2. Create Persistent Volume Claims:

   • Example: You create a PersistentVolumeClaim for MySQL to request storage from the standard-storage class.

   • YAML Definition:

       apiVersion: v1
       kind: PersistentVolumeClaim
       metadata:
         name: mysql-pvc
       spec:
         accessModes:
           - ReadWriteOnce
         storageClassName: standard-storage
         resources:
           requests:
             storage: 10Gi
     

   • Explanation: You create a claim to request 10GB of storage from the standard-storage class for the MySQL database.

3. Attach PVCs to Pods:

   • Example: In your MySQL Deployment, you attach the mysql-pvc to the MySQL pod as a volume.

   • YAML Definition (in Deployment):

       spec:
         volumes:
         - name: mysql-data
           persistentVolumeClaim:
             claimName: mysql-pvc
         containers:
         - name: mysql
           image: mysql:latest
           volumeMounts:
           - mountPath: /var/lib/mysql
             name: mysql-data
     

   • Explanation: You configure the MySQL pod to use the mysql-pvc for data storage.

4. Use the Storage:

   • Example: Your WordPress website writes and reads data to/from the mounted storage provided by the mysql-pvc.

   • Explanation: The WordPress application communicates with the MySQL database through the PVC, ensuring data persistence even if the MySQL pod is rescheduled.

This scenario illustrates how you can ensure that the data for your MySQL database remains persistent in a simple WordPress website deployment in a Kubernetes cluster. The PVC abstracts the storage details, allowing you to focus on your application's functionality while Kubernetes handles the storage management.