An HBase cluster can consist of one or more nodes with its components distributed across the cluster. The major components of HBase cluster are as follows:
Master
RegionServers
ZooKeeper
HBase runs in two modes: standalone and distributed. On a distributed cluster, the Master is typically on the same node as the HDFS NameNode, and the RegionServers are on the same node as a HDFS Datanode, with each RegionServer being collocated with a datanode. For a small cluster, a ZooKeeper may be collocated with the NameNode (not the datanode), but for a large cluster, the ZooKeeper should ...