Master [, Master ...]: with NameNodeHMaster monitors all RegionServer in the cluster. Only one HMaster is active at a time. If it fails, one of the remaining instances takes over.
RegionServer [, RegionServer ...]: with DataNode
Client: connects to a RegionServer identified from the list of RegionServer instances in ZooKeeper
Checklist
addonsdirectoryComponents
HMastermonitors allRegionServerin the cluster. Only oneHMasteris active at a time. If it fails, one of the remaining instances takes over.RegionServeridentified from the list ofRegionServerinstances in ZooKeeperOther Resources