---
source: https://iinventedlight.com/library/notes/kubernetes-persistent-volumes.md
title: "Kubernetes PersistentVolumes and StorageClasses"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "CC BY 4.0 (kubernetes/website); prose restates cited source lines"
attribution: "Summary by iinventedlight (AI-assisted). Sources: Kubernetes Authors, Persistent Volumes, CC BY 4.0 (kubernetes/website); Kubernetes Authors, Storage Classes, CC BY 4.0 (kubernetes/website)."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-04
status: published
checked_on: 2026-11-04
as_of: 2026-11-04
confidence: medium
untested: "No code was run for this note; only the fetched documentation pages were read."
category: coding-references
topic_area: "code-ai-eng: Kubernetes"
tags: ['kubernetes', 'storage', 'persistent-volumes', 'pvc']
sources:
  - id: S1
    title: "Persistent Volumes"
    publisher: Kubernetes Authors
    url: https://kubernetes.io/docs/concepts/storage/persistent-volumes/
    accessed: 2026-11-04
    license: "CC BY 4.0 (kubernetes/website)"
  - id: S2
    title: "Storage Classes"
    publisher: Kubernetes Authors
    url: https://kubernetes.io/docs/concepts/storage/storage-classes/
    accessed: 2026-11-04
    license: "CC BY 4.0 (kubernetes/website)"
---
# Kubernetes PersistentVolumes and StorageClasses

**Answer:** A PersistentVolume (PV) is a piece of cluster storage; a PersistentVolumeClaim (PVC) is a user's request for storage. Pods mount PVCs, and Kubernetes binds each claim to a matching volume.

## Flow

1. Pod spec references a PVC.
2. PVC asks for size, access mode and StorageClass.
3. A matching PV is bound, or the StorageClass provisioner creates one.

```yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata: {name: data}
spec:
  accessModes: [ReadWriteOnce]
  storageClassName: standard
  resources: {requests: {storage: 10Gi}}
```

## Access modes

ReadWriteOnce, ReadOnlyMany, ReadWriteMany, and ReadWriteOncePod.

## StorageClass

Each StorageClass names a provisioner (often a CSI driver), parameters and a reclaim policy. `allowVolumeExpansion: true` lets claims grow. `volumeBindingMode: WaitForFirstConsumer` delays binding until a Pod is scheduled, so the volume lands in the right zone.

## Reclaim

When a claim is deleted, the volume is Retained or Deleted per its reclaim policy.

## Claims
- id: C1
  claim: PersistentVolume and PersistentVolumeClaim are two API resources.
  source: S1
  evidence: "To do this, we introduce two new API resources: PersistentVolume and PersistentVolumeClaim."
- id: C2
  claim: A PersistentVolume is a piece of storage in the cluster.
  source: S1
  evidence: "A PersistentVolume (PV) is a piece of storage in the cluster that has been"
- id: C3
  claim: A StorageClass describes classes of storage.
  source: S2
  evidence: "A StorageClass provides a way for administrators to describe the classes of"
- id: C4
  claim: WaitForFirstConsumer delays binding until a Pod using the claim is created.
  source: S2
  evidence: "will delay the binding and provisioning of a PersistentVolume until a Pod using the PersistentVolumeClaim"

## Sources
- [S1] Persistent Volumes. Kubernetes Authors. https://kubernetes.io/docs/concepts/storage/persistent-volumes/ . License: CC BY 4.0 (kubernetes/website). Accessed 2026-11-04.
- [S2] Storage Classes. Kubernetes Authors. https://kubernetes.io/docs/concepts/storage/storage-classes/ . License: CC BY 4.0 (kubernetes/website). Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).