4. Decommission NodeManagers

On the NameNode host machine, edit the <HADOOP_CONF_DIR>/yarn.exclude file and add the list of NodeManager hostnames (separated by a newline character).

where <HADOOP_CONF_DIR> is the directory for storing the Hadoop configuration files. For example, /etc/hadoop/conf.

If your cluster utilizes a yarn.include file, remove the decommissioned nodes from the <HADOOP_CONF_DIR>/yarn.include file on the ResourceManager host machine.

	Note
	If no yarn.include file is specified, all NodeManagers are considered to be included in the cluster (unless excluded in the yarn.exclude file). The yarn.resourcemanager.nodes.include-path and yarn.resourcemanager.nodes.exclude-path properties in yarn-site.xml are used to specify the yarn.include and yarn.exclude files.

Update the ResourceManager with the new set of NodeManagers. On the ResourceManager host machine, execute the following command:

su <YARN_USER>
yarn rmadmin -refreshNodes

where <YARN_USER> is the user who owns the YARN services, for example, yarn.