It should be possible to make specific reservations for HA vms to make sure that we always have enough spare capacity to start the HA VMs if N hosts fail. This we can do in a basic way with the pluggable scheduler but it would be better if there was a dedicated feature in the engine.
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. http://rhn.redhat.com/errata/RHSA-2014-0506.html