A CounterVector with status as label may create unnecessary overhead
and using the success case with the empty label value wasn't
easy. It's better to have two seperate counters, one for total number
of calls and one for failed calls.
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.
