One more reason to use keepalived instead of heartbeat for this specific purpose. It has the ability to check for the presence and responsiveness of the haproxy process and use that to weigh the priorities and choose which node to elect as the master. Also, the master-backup switching is seamless and extremely fast (only the IP address is enabled/disabled, no process is restarted). A failure is covered in just a few seconds. Heartbeat is for clusters, not for handling virtual addresses.