As discussed during the production readiness review, a metric for the
PVC create operations is useful. The "ephemeral_volume" workqueue
metrics were already added in the initial implementation.
The new code follows the example set by the endpoints controller.
The implementation consists of
- identifying all places where VolumeSource.PersistentVolumeClaim has
a special meaning and then ensuring that the same code path is taken
for an ephemeral volume, with the ownership check
- adding a controller that produces the PVCs for each embedded
VolumeSource.EphemeralVolume
- relaxing the PVC protection controller such that it removes
the finalizer already before the pod is deleted (only
if the GenericEphemeralVolume feature is enabled): this is
needed to break a cycle where foreground deletion of the pod
blocks on removing the PVC, which waits for deletion of the pod
The controller was derived from the endpointslices controller.
