Install a new Ambari-Server on existing HDP stack without data loss

[#1]

Hello there,

We are facing a big problem in our company :

Most of the /var directory was accidentally dropped after a bad log clean in Ambari-Server host.

In the removed files : .map files used to map content in PGSQL. The consequence is that the Ambari-Server can't start anymore. The databases are here but we get "could not find relation mapping" error, so we can't acces it well.

The problem : No DB Backup. No Snaphots. Overall, no directory backup. (Yes i know, this is very bad for a Production cluster...)

The Ambari Cluster is just over since yesterday.

I saw that thread today, but i'm not sure it will be the best issue for us :

https://community.hortonworks.com/questions/6703/ambari-server-installation-after-cluster-setup.html

Infos :

HDP 2.6.1 / Ambari 2.5.1 / PGSQL 9.5

1 Gateway with Ambari-Server (the impacted server) / 2 Masters / 4 Slaves

Our goal is to save the data on the Datanodes and get an Ambari Cluster back.

Any ideas or similar past experiences ?

Thanks all

EDIT 1 : Impacted databases on the host are Ambari / Hive / Oozie / Hue

[#2]

Hi @Manfred PAUL

You are right and we are are currently in Ambari configuration. As the Ambari database was dropped, there is nothing left when you add the hosts.

But we can use XML files on the host to find most of the parameters, they have not been deleted.

We re-installed first, now we are looking for our past specific parameters. This is why backup is important !