Once a cluster is in operation, it may become necessary to change its size or add extra measures for failover scenarios, all while the cluster is in use. Data should be backed up and/or moved between distinct clusters. In this chapter, we will look how this can be done with minimal to no interruption.
This section introduces the various tasks necessary while operating a cluster, including adding and removing nodes.
You can stop an individual region server by running the following script in the HBase directory on the particular server:
./bin/hbase-daemon.sh stop regionserver
The region server will first close all regions and then shut itself down. On shutdown, its ephemeral node in ZooKeeper will expire. The master will notice that the region server is gone and will treat it as a crashed server: it will reassign the regions the server was carrying.
A downside to this method of stopping ...