Major Description
If you download a distribution of bookkeeper-4.2.1 and try to start the bookie before initializing zookeeper, then the bookie will fail to start, but write the local cookie files with a null instance id. If you then initialize zookeeper with the "bin/bookkeeper shell metaformat", you will not be able to start the bookie as instance id of in zk will not match the null instance id in the bookie files.