Introduction
As an SRE working with Kubernetes, you'll occasionally need to rename a PersistentVolumeClaim (PVC) without losing the PersistentVolume (PV) and the data behind it. It comes up when you rename a StatefulSet, or just rename a Helm release for cosmetic reasons, like changing myservice to my-service. Because the PVC name is derived from that name in both cases, a simple redeploy provisions a new PVC, and with it a new, empty PV. If your old PV's persistentVolumeReclaimPolicy is Retain, your data stays unreferenced on the old PV (if it's Delete, the volume is gone the moment you delete the PVC).
To keep the data, your first instinct might be a migration: taking a VolumeSnapshot, running rsync between two mounts, or copying the data out to your local machine and back into the PV. But, in this very specific case, there's an easier way: a PV rebind. Instead of moving any data, you keep the PV as is and just re-point it at the new PVC.
Worth getting the vocabulary straight: this is a rebind, not a migration. Not a single byte moves. For block storage the volume ID stays the same; for NFS the same access point remains.
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