Monitoring Varnish with Heartbeat and Pacemaker

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http://serverfault.com – I have a pair of servers setup as high availability load balancers/reverse proxies. Each runs Ubuntu 12.04 x64 Server, Varnish, Heartbeat and Pacemaker, with Varnish load balancing traffic to back-end servers. If either of the load balancers falls over, Heartbeat/Pacemaker transfers a group of virtual IPs over to the other server, and traffic flow resumes. This bit works fine. What I haven't accounted for is if Varnish isn't running on either server. It's currently possible to stop Varnish without triggering any sort of action from Heartbeat/Pacemaker. I'd like the absense of an operational (HowTos)