Major Description
TestZooKeeper#testRegionAssignmentAfterMasterRecoveryDueToZKExpiry always failed at the following verification for me in my dev env(you have to run the single test not the whole TestZooKeeper suite to reproduce)
assertEquals("Number of rows should be equal to number of puts.", numberOfPuts, numberOfRows);
We missed two ZK listeners after master recovery MasterAddressTracker & ZKNamespaceManager.
My current patch is to fix the JIRA issue while I'm wondering if we should totally remove the master failover implementation when ZK session expired because this causes reinitialize HMaster partially which is error prone and not a clean state to start from.