ZOOKEEPER-1333 is the most serious of the issues addressed, it could cause a server to fail to rejoin the quorum on restart:
- ZOOKEEPER-1333 NPE in FileTxnSnapLog when restarting a cluster
If you are running 3.4.1 or earlier be sure to upgrade immediately. See my earlier post for details on what’s new in 3.4.
Stability, Compatibility and Testing
It is important to note that 3.4.2 is not yet ready for production. It is an early release that users can start testing so that we can stabilize later 3.4.x releases. We expect a dot release to be production-ready soon, and to be incorporated into CDH4.
The Apache ZooKeeper project is working on a number of new features. Our How To Contribute page is a great place to start if you’re interested in getting involved as a developer. You can also follow me on twitter.
A special thanks to everyone who contributed to the release (reporting issues, fixing bugs, reviewing changes, writing documentation, etc).