There are hundred different ways of distributing search traffic over a farm of search engines. From hard-coded configuration to multi-casted message-bus. If not hard to implement, they are hard to understand for someone starting out with search-engines. But not so with bonjour, which is P2P service announcement of sorts. Assuming bonjour server/client you are using is avahi, just run avahi-browse to find what services are running in current network. Offcourse, not great if farm spans more than one network. But its so easy. I am surprised, its so easy to announce and discover.