when the systemd cgroup manager is used, controllers not handled by
systemd are created manually afterwards.
libcontainer didn't correctly cleanup these cgroups that were leaked
on cgroup v1.
Closes: https://github.com/kubernetes/kubernetes/issues/92766
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
PR opencontainers/runc#1754 works around an issue in manager.Apply(-1) that
makes Kubelet startup hang when using systemd cgroup driver (by adding a
timeout) and further PR opencontainers/runc#1772 fixes that bug by
checking the proper error status before waiting on the channel.
PR opencontainers/runc#1776 checks whether Delegate works in slices,
which keeps libcontainer systemd cgroup driver working on systemd v237+.
PR opencontainers/runc#1781 makes the channel buffered, so if we time
out waiting on the channel, the updater will not block trying to it
since there are no longer any consumers.
