How to get remote access to a linux server if there is a problem when starting the OS?

Question

linux

Real life example: there is a regular computer with Ubuntu Server 12.04 open on the Internet. Once I decided to update it to 14.04 (well, he asked very insistently at every login). I updated it, and after the next reboot I lost access to it (the computer, as I was told, was physically working), but there was no access via ssh and none of the software that started automatically worked. How can I configure the PC / set up / install something in order to be able to solve the problem remotely in this case? Is there anything for remote access to grub?

Answer 1

IP-KVM is a must have. This is either a device that is plugged in instead of a monitor, mouse, keyboard (Keyboard, Video, Mouse, catch it?) Or a board inside the server, from which it can be controlled even through a browser. Different offices have different names (IPMI, iLO, and so on.)

Answer 2

1. if this is a colocation, then ask for ipkvm
2. either from the console, ask the person to come up to enter a number of commands (run the same sshd), but you will have to hand over the password
3. come up yourself
4. ask for a computer to be brought to you
otherwise nothing