persistentvolumeclaims

In Kubernetes, a PersistentVolumeClaim (PVC) is a request for storage by a user. It abstracts the details of how storage is provided and consumes a PersistentVolume (PV) that satisfies the claim’s requirements. PVCs are namespace-scoped, while PVs are cluster-scoped.

A PVC specifies the requested resources, including the storage size, access mode (ReadWriteOnce, ReadOnlyMany, ReadWriteMany), and optionally a storageClassName. It may also specify the volumeMode (Filesystem or Block). When a PV that matches the claim’s requirements exists, the control plane binds the PVC to that PV, and the PV’s name is recorded in the PVC’s volumeName field.

Dynamic provisioning is possible when no suitable PV exists. A StorageClass can be configured to dynamically provision PVs, enabling automatic creation of storage that satisfies the PVC. The PVC remains in Pending status until a binding occurs, and the resulting PV must be compatible in size, access mode, and other properties.

Usage involves attaching the claimed storage to a pod by referencing the PVC in a volume definition and mounting it inside the container. The lifecycle begins with claim creation, followed by binding, volume usage by the pod, and eventual PVC deletion. When a PVC is deleted, the PV’s reclaimPolicy determines what happens to the underlying storage: Retain keeps the PV and its data, Delete removes the storage (and may delete the data), while Recycle is deprecated in favor of other options.

Resizing of a PVC is possible in some environments if the underlying storage supports it and the feature is enabled. PVCs provide a stable abstraction for persistent storage across pod lifecycles.