Persistent Volume Claims (PVC) represent a request to use a persistent volume (PV) with a pod. When creating a pod  definition (or replication controller or deployment config) a developer may specify the amount of storage they need via a persistent volume reference. If an administrator has enabled and configured persistent volumes for use, they will be allocated on demand to pods that have similar requirements. Since volumes are created lazily, some pods  may be scheduled to a node before their volume is assigned. The node will detect this situation and wait to start the pod until the volume is bound. Events will be generated (visible by using the `describe` command on the pod) that indicate the pod is waiting for volumes.