block the creation of a pod that requires a user namespace, unless the
runtime handler has support for it.
If the pod requested for a user namespace, and the handler does not
support it then return an error regardless of the feature gate.
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
This commit adds a new volume manager in kubelet that synchronizes
volume mount/unmount (and attach/detach, if attach/detach controller
is not enabled).
This eliminates the race conditions between the pod creation loop
and the orphaned volumes loops. It also removes the unmount/detach
from the `syncPod()` path so volume clean up never blocks the
`syncPod` loop.
