The Apache BookKeeper subproject of ZooKeeper is made up of two major components:
- A distributed logging service called BookKeeper.
- A distributed topic based publish/subscribe service called HedWig.
We have implemented a JournalManager for Hadoop HDFS which allows you to run a high availability cluster using BookKeeper as shared storage. Details on this can be found in HDFS BookKeeperJournalManager.
Roadmap for work.