Ambari Server and Multiple Postgres versions?

[#1]

Hello,

I'm running into an issue related to a system that has two different versions of postgres installed. The system is running ambari 2.7.3.0 and my intention is for to run ambari server with postgres v10. However I recently noticed it was running with verision 9.2. I could tell b/c the postgres 9.2 service was active while the postgresql-10 service was inactive. Back when I upgraded the system to ambari 2.7.3.0 I confirmed it was up and running with postgres10 but after rebooting the machine I noticed it's now running with version 9.2. Is there an ambari configuration/setting that tells it which version of postgres to choose/run with? 

[#2]

@rwinters 

Simplest method is to edit /etc/postgresql/9.2/main/start.conf and replace auto with manual or disabled.

You can also resolve this by adding the following to the end of your shell's initialisation file (e.g. ~/.bashrc if you're using bash):

PATH=/usr/psql-10/bin:$PATH

reboot the server  now you should have the postgres 10 as the default

Hope that helps

[#3]

Thanks this is helpful, but I was curious. If there are versions of postgres installed on the system, how does ambari-server choose which one to run with? I actually have another system where I'm seeing the opposite. In this case postgresql-10 is running and postgresql (9.2) is not active after a restart. I'm just trying better understand how it choose which postgres service to start?