Persistent Volume Management Operator
Learn about the PVMO in CKS
Persistent Volume Management Operator
CKS features a Persistent Volume Management Operator (PVMO). PVMO is a Kubernetes controller manager that runs periodically to clean up orphaned volumes.
PVMO tracks PVC delete events through admission webhooks. If it finds a delete event, it adds the label pv-failsafe.coreweave.cloud/<deletion-timestamp> - where deletion-timestamp is the current time - to the Persistent Volume to which the PVC was attached.
The PVMO also adds a watcher service that periodically lists all Persistent Volumes in the cluster.
By default, the watcher lists all PVs in the cluster once per hour.
The watcher service checks for any "orphaned" PVs. A PV is considered "orphaned" if it has been released from its PVC and does not have the soft delete label described above. If the watcher finds an orphaned PV, it adds the soft delete label to it.
The watcher service also checks Persistent Volumes to see if they are eligible for deletion. To be eligible, a PV must feature the soft delete label, and must have exceeded the soft delete window.
The default soft delete window for PVs is 24 hours.
If both of these conditions are met, the PVMO updates the reclaim policy on the PV from Retain to Delete. This update means that the PV gets reclaimed by CKS and all of its underlying volumes are deleted.
To learn more about creating a Distributed File Storage volume, see: How To: Create a Distributed File Storage Volume.