I've used ZooKeeper not only as a service registry but also as a fairly small message queue - I wanted to be sure that my message will be delivered at least onc

I've used ZooKeeper not only as a service registry but also as a fairly small message queue - I wanted to be sure that my message will be delivered at least once, and thanks to Kazoo's (Python ZK library) LockingQueue recipe I was able to get what I want really easily with all the benefits from ZK's clustering nature.