[clizzin]

Hey there, thanks for your interest!

Our service discovery system is indeed a layer that sits between ZooKeeper and the application. But it's also pluggable -- that means that you don't have to use ZooKeeper as the system that tracks which service nodes are available; you can use something else, and write a plugin for our service discovery system that will talk to that instead. So it's not necessarily a layer on top of ZooKeeper, although we certainly use it that way.

I don't want to say too much about the technical details yet since we're still rolling it out in production and may change some pieces before it's released. Also, I'm not one of the primary authors and don't want to steal their thunder. ;) But yes, we do plan to open source it once the code is fairly stable (and once we have some time to jump through all the usual hoops of open sourcing code), and then we'll do a detailed post about how it all works. It's really cool and stunningly simple.