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Persistent Volume Claims

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  • A Persistent Volume Claim is a request for storage by a user or an application.
  • Users don’t deal with how the storage is provisioned they just ask for how much they need
  • Kubernetes tries to match the claim with a suitable Persistent Volumes.
  • Once matched, the PV and PVC are bound one-to-one

How Binding Works

  • First it finds a PV that has equal or more capacity than requested.
  • If it matches Access Modes (Access Modes), and StorageClass it is automatically binded
  • But if multiple volumes are suitable, you can use Labels And Selectors to target a specific PV.
  • If no suitable volume is available then PVC remains in Pending state and once a matching PV is added, it binds automatically.

PVC Example Manifest

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: myclaim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Mi

One-to-One Binding

  • A PVC is bound to only one PV. Even if the PV has more capacity than requested, it can’t be split across multiple claims.

For example:

  • Claim requests 500Mi
  • PV has 1Gi
  • PVC is binded to that PV
  • The remaining 500Mi is unused and unavailable to other claims

When a PVC is Deleted?

The persistentVolumeReclaimPolicy of the PV determines the behavior:

1. Retain (default)

  • PV remains even if the PVC is deleted.
  • Admin must manually delete or reuse the volume.

2. Delete

  • Underlying storage is automatically deleted when the PVC is deleted.

3. Recycle (deprecated)

  • PV is scrubbed and reused for future claims.

Commands

  • Create PVC

kubectl create -f pvc.yaml

  • Get PVC

kubectl get pvc

⬅️ Persistent Volumes | StorageClass ➡️

References

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