Kestrel is a port of Blaine Cook’s “starling” message queue system from ruby to scala: http://rubyforge.org/projects/starling/
Starling is a powerful but simple messaging server that enables reliable distributed queuing with an absolutely minimal overhead. It speaks the MemCache protocol for maximum cross-platform compatibility. Any language that speaks MemCache can take advantage of Starling’s queue facilities.
In many situations, loose ordering is sufficient. Dropping the requirement on cross communication makes it horizontally scale to infinity and beyond: no multicast, no clustering, no “elections”, no coordination at all. No talking! Shhh!
Kestrel adds several additional features, like ginormous queues, reliable fetch, and blocking/timeout fetch — as well as the scalability offered by actors and the JVM.