Volumes & persistent storage

0 / 15 lessons — 0%

Lesson 07 / 15

Pods are disposable by design — restart one and its local filesystem is wiped clean. For anything that needs to survive that (a database, uploaded files), Kubernetes separates what storage you want from where it physically lives, through three objects working together.

Object	Role
StorageClass	A "menu" of available storage types (fast SSD, slow HDD, cloud disk...)
PersistentVolume (PV)	An actual chunk of storage that's been provisioned
PersistentVolumeClaim (PVC)	A Pod's request — "I need 10GB, fast tier" — matched to a PV


# pvc.yaml — a pod-facing request for storage
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: db-storage
spec:
  accessModes: ["ReadWriteOnce"]
  storageClassName: standard
  resources:
    requests:
      storage: 10Gi


# mounting it into a pod
spec:
  containers:
    - name: postgres
      image: postgres:16
      volumeMounts:
        - mountPath: /var/lib/postgresql/data
          name: data
  volumes:
    - name: data
      persistentVolumeClaim:
        claimName: db-storage

Same idea as Docker volumes, one abstraction layer up: a PVC is basically "please give me a Docker-volume-like thing," and Kubernetes figures out which underlying disk actually satisfies it — often provisioning real cloud storage (an AWS EBS volume, an Azure Disk) on demand.

Try it yourselfAfter applying a PVC, run kubectl get pvc and check its STATUS column — Bound means Kubernetes found or created a matching PersistentVolume for it.

← Lesson 06 Next: Lesson 08 →