Persistent Volume Claim Guide

PersistentVolumeClaim (PVC)¶

A PersistentVolumeClaim (PVC) is a request for storage by a user. It specifies size, access modes, and storage class. The developer or app owner, usually within a namespace, creates a PVC.

Key Characteristics:¶

• Namespace-scoped object.
• Describes how much space is needed and how it should be accessed (ReadWriteOnce, ReadOnlyMany, etc).
• Kubernetes will bind a matching PV with the PVC.

Key Fields in PVC YAML¶

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-manual
spec:
  accessModes:
    - ReadWriteOnce  # Can be mounted on one node # Matches the PV
  resources:
    requests:
      storage: 10Gi  # Requested size # Must be <= available PV
  storageClassName: manual  # Matches the PV or StorageClass
# storageClassName: aws-ebs
# storageClassName: nfs
# storageClassName: csi-sc

• The value of storageClassName is not fixed; it can be any name, but it must match the name of the StorageClass or the value in the PV and PVC manifest for proper binding.
• This PVC will only bind to a PV that also has storageClassName: manual.

📌 PVC binds to a suitable PV if accessModes, storageClassName, and requests.storage match.

⚙️ Using PVC in a Pod (Claims As Volumes)¶

apiVersion: v1
kind: Pod
metadata:
  name: app-using-pvc
spec:
  containers:
    - name: myapp
      image: nginx
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"  # Where the data will appear in container
          name: html-volume
  volumes:
    - name: html-volume
      persistentVolumeClaim:
        claimName: pvc-manual # The PVC we created earlier # This PVC must already exist

🧠 Breakdown:¶

This ensures data persists even if the Pod is restarted or rescheduled on a different node.