I have decommissioned one node from my cluster.I included that host name in dfs.exclude, and yarn.exclude. Still ambari is showing as dead node. How to make ambari forget about the decommissioned host from cluster?
Please see the official doc on decommission process http://docs.hortonworks.com/HDPDocuments/Ambari-188.8.131.52/bk_Ambari_Users_Guide/content/_how_to_decomm...
If you are using Ambari to manage the cluster then Don't decomsission manually.
I face the same problem, the alert with dead nodes doesn't clear.
The nodes were decommissioned and removed from the cluster, ambari agent is not running and i also ran the refreshnodes command.
Which services may require restart?
I got the solution for this. After decommissioning the node, first you need to check /etc/hosts file whether decommissioned host is present or not on Name node host. I am sure, it will be there, try to delete that decommissioned host name and restart Namenodes, later check /etc/hosts file. You need to restart the HDFS and Mapreduce i believe, anyway it will show you on ambari dash board which services need to be restarted. Thank you and let me know it is worked for you or not. It worked for me.