Kubernetes Persistent Volumes and PVCs Guide

💡 Quick Answer: Create and manage Persistent Volumes and PersistentVolumeClaims in Kubernetes. Covers StorageClasses, dynamic provisioning, access modes, and volume expansion.

The Problem

This is one of the most searched Kubernetes topics. Having a comprehensive, well-structured guide helps both beginners and experienced users quickly find what they need.

The Solution

PersistentVolumeClaim (Dynamic Provisioning)

# Most common — let StorageClass handle it
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-data
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: gp3          # Cloud provider StorageClass
  resources:
    requests:
      storage: 50Gi
---
# Use in a pod
apiVersion: v1
kind: Pod
spec:
  containers:
    - name: postgres
      image: postgres:16
      volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/data
  volumes:
    - name: data
      persistentVolumeClaim:
        claimName: postgres-data

StorageClass

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-ssd
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: ebs.csi.aws.com
parameters:
  type: gp3
  iops: "5000"
  throughput: "250"
  encrypted: "true"
reclaimPolicy: Delete      # or Retain
allowVolumeExpansion: true  # Allow PVC resize
volumeBindingMode: WaitForFirstConsumer  # Bind when pod is scheduled

Access Modes

Expand a PVC

# Edit the PVC size (StorageClass must allow expansion)
kubectl patch pvc postgres-data -p '{"spec":{"resources":{"requests":{"storage":"100Gi"}}}}'

# Check status
kubectl get pvc postgres-data
# Condition: FileSystemResizePending → resize happens on next pod mount

Static PersistentVolume

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-data
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteMany
  nfs:
    server: nfs.example.com
    path: /exports/data
  persistentVolumeReclaimPolicy: Retain

graph TD
    A[PVC Request: 50Gi RWO] --> B{StorageClass}
    B -->|Dynamic provisioning| C[Cloud creates disk]
    C --> D[PV auto-created]
    D --> E[PVC bound to PV]
    E --> F[Pod mounts volume]

Frequently Asked Questions

What happens when I delete a PVC?

Depends on reclaimPolicy: Delete removes the underlying storage. Retain keeps the data but the PV becomes Released and can’t be reused without manual cleanup.

PV vs PVC?

PV is the actual storage resource. PVC is a request for storage. PVCs bind to PVs. With dynamic provisioning, you only create PVCs and the PV is auto-created.

Best Practices

• Start simple — use the basic form first, add complexity as needed
• Be consistent — follow naming conventions across your cluster
• Document your choices — add annotations explaining why, not just what
• Monitor and iterate — review configurations regularly

Key Takeaways

• This is fundamental Kubernetes knowledge every engineer needs
• Start with the simplest approach that solves your problem
• Use kubectl explain and kubectl describe when unsure
• Practice in a test cluster before applying to production