https://github.com/openshift/ose/pull/751
Tested on OCP build v3.5.5.21 with openshift-on-openstack env, Issue has been fixed, the node host IP will not flip flop during the master and node restart.
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-2017:1425