Ambari server doesn't restart after removing node with cloudbreak - postgresql

Question

After adding a node to test scaling then removing that node with cloudbreak, the service ambari-server won't restart.
The error at launch is:
DB configs consistency check failed. Run "ambari-server start --skip-database-check" to skip. You may try --auto-fix-database flag to attempt to fix issues automatically. If you use this "--skip-database-check" option, do not make any changes to your cluster topology or perform a cluster upgrade until you correct the database consistency issues. See /var/log/ambari-server/ambari-server-check-database.log for more details on the consistency issues.
Looking the logs doesn't say much more. I tried restarting postgres, sometimes it works, like 1 on 10 times (HOW is it possible ?)

Answer 1

I went deeper in my reasonning rather than just restarting postgres.
I opened the ambari table to look in it:
sudo su - postgres
psql ambari -U ambari -W -p 5432
(password is bigdata)
and when I looked in tables topology_logical_request, topology_request and topology_hostgroup, I saw that the cluster register a remove request, only an adding request:
ambari=> select * from topology_logical_request;
id | request_id | description
----+------------+-----------------------------------------------------------
1 | 1 | Logical Request: Provision Cluster 'sentelab-perf'
62 | 51 | Logical Request: Scale Cluster 'sentelab-perf' (+1 hosts)
Check the ids to delete (track all requests with adding node operation) and begin to delete them (order matters):
delete from topology_hostgroup where id = 51;
delete from topology_logical_request where id = 62;
DELETE FROM topology_request WHERE id = 51;
close with \q, restart ambari-server, and it works !