PersistentVolumes

PersistentVolume is a piece of storage in a Kubernetes cluster that has been provisioned for use by pods. It represents an actual storage resource in the underlying infrastructure, such as a cloud disk, an NFS share, or a block device. PVs are cluster-scoped resources.

A PersistentVolumeClaim is a request for storage by a user or application. The control plane binds an appropriate PV to a PVC based on budgeted capacity and access modes. A pod accesses storage by mounting the claim through the PVC.

PVs can be statically provisioned by administrators or dynamically provisioned using StorageClasses. Dynamic provisioning uses a provisioner to create storage in the backend when a PVC is created, and then binds the resulting PV to the PVC.

The PV specification includes fields such as capacity (storage size), accessModes, persistentVolumeReclaimPolicy, storageClassName, and a source that identifies the underlying storage (for example CSI or an in-tree driver).

Access modes describe how the volume can be mounted: ReadWriteOnce, ReadOnlyMany, and ReadWriteMany. ReclaimPolicy determines what happens to the storage after a PVC is released, with Delete and Retain as common options.

PV resources are non-namespaced, whereas PVCs are namespaced. The typical lifecycle is Available, Bound, and Released. After release, the PV may be deleted or retained according to its reclaim policy and provisioning method.