I have Ambari and HDP installed on an AWS cluster of four nodes. One of my nodes died and is no longer accessible (can not talk to it and it does not talk to anyone else). I am okay with the data loss but don't know how to tell Ambari to let go of that particular host. What should I do?
If you did not have any masters on this host, you may want to follow this manual
I'd expect that HDFS supports the removal of an inaccessible datanode.
But if you had masters on this host, that is major trouble and I'd expect that removing the dead host is not supported by Ambari (without manual database edits)
You may also want to ask at https://community.hortonworks.com/, maybe somebody suggests a workaround (some kind of dirty hack)