Your restart command for agents is correct.   Did your agents change host names / ip addresses as well? It sounds like your hosts page has two entries for each host, one with the new name, one with the old. In this case, you need to tell your agents to use the old host id. You don't want to use the new host id because you'll have to re-configure all of your role assignments. Edit /etc/default/cloudera-scm-agent and set CMF_AGENT_ARGS="--host_id xxx" where xxx is your old host id. You can find the old host id by clicking on your old host in the Hosts tab and looking at what is listed for Host ID.   Restart your agents after changing /etc/default/cloudera-scm-agent.   On the Hosts page, you should see all of your old hosts (the ones with roles assigned to them) have recent heartbeats and good health. You can delete the copies that have no heartbeats and no roles. If you don't see this, then let us know what you see so we can fix it.   Now Cloudera Manager is correctly in contact with all of your hosts again. You can run the restart command through the Cloudera Manager UI. You can restart an individual service or the whole cluster by clicking on the appropriate dropdown menu (small button with a triangle).   Thanks, Darren ... View more