K8s Storage class, PV, and PVC

Kubernetes provides several mechanisms for managing storage in a cluster, including volumes, persistent volumes (PVs), and storage classes.

• Persistent Volume: Kubernetes has storage devices used in the cluster — SSD, NVMe disks, NAS, NFS servers.
• Volume: At its core, a volume is a directory, possibly with some data in it, accessible to the containers in a pod. A process in a container sees a filesystem view composed from the initial contents of the container image, plus volumes (if defined) mounted inside the container.
• Storage Class: Dynamic provisioning of persistent volumes
• Projected Volumes: secret, downwardAPI, configMap, serviceAccountToken (multiple source of data into a single volume within a pod)
• Ephemeral Volumes: emptyDir, configMap, downwardAPI, secret, CSI ephemeral volumes, generic ephemeral volumes (This is typically non-persistent data like deleted when the pod is terminated or rescheduled)

Sample YAML files

(1) Persistent Volume

apiVersion: v1
kind: PersistentVolume
metadata:
  name: my-pv
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: my-storage-class
  hostPath:
    path: /data/my-pv

---
apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
    - name: my-container
      image: nginx
      volumeMounts:
        - name: my-volume
          mountPath…