I think you're probably right about ensemble setup overhead not mattering very much if you are creating a cluster in your own datacenter for your own apps. In m

I think you're probably right about ensemble setup overhead not mattering very much if you are creating a cluster in your own datacenter for your own apps. In my case, I need to bootstrap an ensemble in someone else's datacenter without a priori knowledge of ip addresses. I don't mean to be totally negative. I really respect what the zk team has done and it's a fantastic tool that is often and unfortunately overshadowed by Hadoop. I think a small, reliable, coordination cluster providing atomic distributed primitives is an excellent distributed system architecture. Obviously Google and Yahoo have had success with it. I just recently learned that Ceph takes a similar approach.