how to remove old registered hosts from DB

[#1]

I am trying to remove old worker from the DB ( from ambari-server machine ) as the following

* reference - https://community.hortonworks.com/questions/52910/how-can-i-remove-registered-host-but-do-not-added....

psql -U ambari ambari

Password for user ambari:

ambari-> select host_id from hosts where host_name='worker05.sys59.com';

host_id 

---------

255 

(1 row)

so I delete the host:

ambari=> Delete from hoststate where host_id=255
ambari-> Delete from hosts where host_id=255

ambari=> select host_id from hosts where host_name='worker05.sys59.com';
host_id ---------
255 (1 row)

this worker still exists in DB , ( host_id=255 ) , even I restart the ambari-server !!

why?

and how to total remove this worker include all worker properties from postgreSQL ?

[#2]

@Michael Bronson,

Add a semicolon at the end of the statement

ambari=> Delete from hoststate where host_id=255;
ambari=> Delete from hosts where host_id=255;

Note: Do the above with caution. Before removing the node from cluster it is advised to move all the services to other nodes and make sure that the node is clean before deleting the node.

Below is the API to delete the node

curl -u {ambari-user}:{ambari-password} -H "X-Requested-By: ambari"-X DELETE  http://{ambari-host}:{ambari-port}/api/v1/clusters/{clustername}/hosts/{hostname}

Thanks,

Aditya

[#3]

I am usually remove it by the amabri GUI ( dlete node ) , but I guess the API do the same ? 

[#4]

@Michael Bronson,

Yes. Ambari calls the same API internally. If you want to run it from command line instead of Ambari GUI , you can use the API.

That should take care of clearing the entries from DB. You need not delete the entries from DB manually

[#5]

now after we delete the worler06 now we want to add it to the cluster but we get from the ambari GUI:

we waiting more then 20min - is it logical ?

Please wait while the hosts are being checked for potential problems...         

[#6]

@Michael Bronson,

It shouldn't take so long. Please check the ambari log to see what is going wrong.

Check this file /var/log/ambari-server/ambari-server.log in ambari server node

[#7]

the deleted host - worker 06 only deleted and we not removed the worker component , so now when we add this worker again mayby this is the conflict because worker is already installed ?|

[#8]

@Michael Bronson,

If the host deletion was not proper then there can be conflicts. The ambari log below doesn't show any errors. Try restarting ambari server and see if you can proceed further.

ambari-server restart

[#9]

from the ambari-server log we see that

 configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:37,189  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:37,189  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:38,222  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:38,222  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:38,222  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:39,247  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:39,247  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:39,247  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:40,272  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:40,273  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
05 Dec 2017 16:33:40,273  WARN [ambari-action-scheduler] ExecutionCommandWrapper:185 - Unable to lookup the cluster by ID; assuming that there is no cluster and therefore no configs for this execution command: Cluster not found, clusterName=clusterID=-1
^C

[#10]

another issue I have about :

ambari=> Delete from hosts where host_id=351;
ERROR:  update or delete on table "hosts" violates foreign key constraint "fk_host_role_command_host_id" on table "host_role_command"
DETAIL:  Key (host_id)=(351) is still referenced from table "host_role_command".