https://github.com/openshift/origin/pull/20358
We have tested this in rpm install and system container install. Flexvolume works for containerized kubelet.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2018:2652