As documented in the linked kbase, the default setting for HandlePowerKey in /etc/systemd/logind.conf causes systemd to attempt a graceful shutdown when IPMI-based fence agents attempt to fence a system. https://access.redhat.com/solutions/1578823 This setting should be changed (either in the overcloud-full image or during deployment).
*** This bug has been marked as a duplicate of bug 1242422 ***