In some intstances (e.g. while resolving an error) it's possible for a
hung process to hang the entire cluster as they wait for its response.
The cluster can handle terminated processes but hung processes present
a problem.
If the watchdog plugin is loaded and --watchdog-interval is set then
the broker forks a child process that runs a very simple watchdog
program, and starts a timer in the broker process to signal the watchdog
every interval/2 seconds. The watchdog kills its parent if it does not
receive a signal for interval seconds. This allows a stuck broker to be
removed from the cluster so other cluster members can continue.
git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@802927 13f79535-47bb-0310-9956-ffa450edef68