How to install a Linux distribution on an old android phone?

I have an old android phone that I would like to install a linux distrobution on. I see many tutorials that involve running a virtual machine on top of android, however this is not what I want. I want to install linux directly on the hardware. I want to run an apache server on it with a distribution like CentOS, so I do not want a fancy desktop environment, but I would like it to have a virtual keyboard to manage it. Otherwise, how would I connect to it using my USB keyboard? How would I install it onto my phone?