PVC PersistentVolumeClaim
Kubernetes' way of asking for storage. A pod doesn't mount a disk directly; it claims "20 GB of this storage class", and the cluster binds it to a PersistentVolume.
The abstraction is the point: the application manifest never mentions EBS, Ceph or NFS, only a storage class. A CSI driver provisions the volume dynamically when the claim appears. The access mode determines usage — ReadWriteOnce (one node, what block-based cloud storage provides), ReadWriteMany (many nodes, requires file-based storage such as NFS or CephFS), ReadWriteOncePod. A StatefulSet creates its own PVC per replica through volumeClaimTemplates, and those survive pod restarts. Classic trap: a reclaim policy of Delete means the data disappears along with the claim.