Hadoop provides the decommission feature to retire a set of existing slave nodes (DataNodes, TaskTrackers, or HBase RegionServers) in order to prevent data loss.
Slaves nodes are frequently decommissioned for maintainance. As a Hadoop administrator, you will decommission the slave nodes periodically in order to either reduce the cluster size or to gracefully remove dying nodes.
Use the following sections to decommission slave nodes in your cluster:
