Getting ZooKeeper server version via Java API

Question

I'm finding that some Apache Curator recipes don't work with older versions of ZooKeeper. This isn't an issue except that I keep having developers in my company try to use some code I wrote and it fails without any errors or log messages due to them running an old version of their local machine. So I want to retrive the version of the ZooKeeper server to which I'm connected and die with an useful error message if the version is too old. However, I can't find any way to get the server's version number with either the Curator or ZooKeeper APIs. Anyone know how to do it?

Answer 1

The ZooKeeper "four letter words" can help. You can connect to the local ZK instance on port 2181 and execute a "srvr" four letter word. You'll get back lines of info one of which is the version.

Have a look at Exhibitor's FourLetterWord class for a sample of how to get this programmatically: https://github.com/Netflix/exhibitor/blob/40a02452dc3133fe37bf4ecf076bda99c29ab6ec/exhibitor-core/src/main/java/com/netflix/exhibitor/core/state/FourLetterWord.java