@Michael Bronson You can try the following approach to completely remove the unwanted host from your ambari Database. 0. Stop ambari-server. # ambari-server stop 1. Please take a fresh ambari DB dump for safety and backup. 2. Now run the following SQL queries inside your ambari DB to delete the unwanted host. Please replace the "unwanted1.host.com" with your unwanted hostname and similarly the "351" with the "host_id" that you want to remove from your Database. delete from execution_command where task_id in (select task_id from host_role_command where host_id in (351)); delete from host_version where host_id in (351); delete from host_role_command where host_id in (351); delete from serviceconfighosts where host_id in (351); delete from hoststate where host_id in (351); delete from kerberos_principal_host WHERE host_id='unwanted1.host.com'; ----> For kerberized Env delete from hosts where host_name in ('unwanted1.host.com'); delete from alert_current where history_id in ( select alert_id from alert_history where host_name in ('unwanted1.host.com')); 3. Now restart ambari-server. # ambari-server start . ... View more

Is passwordless installed between the namenode and secondary namenode ( or standby if you are HA ) can you check in the namenode UI the checkpoints ? ... View more

@Michael Bronson, This is because of dependency between the services. These are defined in role_command_order.json. If there is no dependency for the component it can run in parallel between the nodes. However in a particular node the execution will be sequential. You can check the role_command_order.json for different services and their dependencies. Just run the command in ambari server to find all the json files. find /var/lib/ambari-server/ -iname role_command_order.json Thanks, Aditya ... View more