PVC Storage Provisioning in Kubernetes

💡 Quick Answer: storage

The Problem

This is one of the most searched Kubernetes topics with thousands of monthly searches. A comprehensive, production-ready guide prevents hours of trial and error.

The Solution

Dynamic Provisioning (Recommended)

# StorageClass (usually pre-configured by cloud provider)
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-ssd
provisioner: ebs.csi.aws.com
parameters:
  type: gp3
  iops: "3000"
allowVolumeExpansion: true
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
---
# PVC — automatically creates PV
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-data
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: fast-ssd
  resources:
    requests:
      storage: 50Gi
---
# Use in Pod
apiVersion: v1
kind: Pod
metadata:
  name: postgres
spec:
  containers:
    - name: postgres
      image: postgres:16
      volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/data
  volumes:
    - name: data
      persistentVolumeClaim:
        claimName: postgres-data

Access Modes

Static Provisioning

# Pre-create PV (NFS, hostPath, existing disk)
apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-data
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteMany
  nfs:
    server: nfs.example.com
    path: /exports/data
  persistentVolumeReclaimPolicy: Retain
---
# PVC binds to matching PV
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: shared-data
spec:
  accessModes: [ReadWriteMany]
  resources:
    requests:
      storage: 100Gi
  storageClassName: ""   # Empty = static binding

Common Operations

# List PVCs and PVs
kubectl get pvc
kubectl get pv

# Expand PVC (StorageClass must have allowVolumeExpansion: true)
kubectl patch pvc postgres-data -p '{"spec":{"resources":{"requests":{"storage":"100Gi"}}}}'

# Check binding
kubectl describe pvc postgres-data

graph TD
    A[PVC: 50Gi RWO] -->|Dynamic| B[StorageClass creates PV]
    A -->|Static| C[Binds to matching PV]
    B --> D[Cloud disk provisioned]
    D --> E[PV Bound to PVC]
    E --> F[Pod mounts volume]
    G[PVC deleted] -->|Retain| H[PV remains - manual cleanup]
    G -->|Delete| I[PV + disk deleted]

Frequently Asked Questions

PV vs PVC?

PV is the actual storage resource (like a disk). PVC is a request for storage (like an order). Dynamic provisioning creates PVs automatically when you create PVCs.

PVC stuck in Pending?

Check: StorageClass exists? Cloud credentials? Available capacity? Node in same zone? Use kubectl describe pvc — the Events section tells you why.

Best Practices

• Start with the simplest configuration that solves your problem
• Test in staging before production
• Use kubectl describe and events for troubleshooting
• Document team conventions for consistency

Key Takeaways

• This is fundamental Kubernetes operational knowledge
• Follow established conventions and recommended labels
• Monitor and iterate based on real production behavior
• Automate repetitive tasks to reduce human error