Wackamole is a tool that helps with making a
cluster highly available. It manages a bunch of
virtual IPs that should be available to the outside
world at all times, and ensures that exactly one
machine within the cluster is listening on each
virtual IP address that Wackamole manages. If it
discovers that particular machines within the
cluster are not alive, it will almost immediately
ensure that other machines acquire the virtual IP
addresses the down machines were managing. At
no time will more than one connected machine be
responsible for any virtual IP.