I am trying to track down the reason my Ubuntu server is going into sleep suddenly.
This is always happening a few minutes after a reboot. My problem is I don't have a clue about where to look to understand the reasons for this. This is an 18.04 machine running Ubuntu server.
I rarely have to restart and when I do, things work fine, I can ssh into the machine again, start using it and after some time (probably less than 15 minutes), my ssh session freezes. I end up having to call the data centre for someone to restart my server and I'm being told that they found the server in a suspended state. Once someone physically restarts the server, all is well until I have to perform a reboot again.
Which logs or configuration settings I should check to find the reason behind this behaviour? I've seen this happen to my 16.04 and 18.04 servers both.