reverse engineering things that predecessors left without any documentation and throwing them out the window because devops

This one bugged me for a while. Whenever I would reboot my CentOS 7 server with Xen kernel, my console/framebuffer resolution would be terribly low. Since we live in 2016 and have huge monitors, there is no reason to use 800×600 for your screen resolution. Yes, it’s nice to keep your text editing to 79 columns, but these days we just do more than edit text in terminals (see tmux).

Anyway, to set a new console resolution in CentOS 7 with Xen kernel (on a dom0 of course), head over to /etc/default/grub.

If you are using Xen kernel, your grub config will will look like this:

Edit the file so it looks like this:

In this case we added the following lines:

Generate the new grub config file in /boot:

You should see something like this:

Now what we’ve done is remove the console handling stuff (I don’t use a serial console on my home hypervisor, but in a datacenter? Yes please!) and added the GRUB_GFXMODE and GRUB_GFXPAYLOAD settings. After rebooting the machine, you should see everything in a higher, crisper resolution on your monitor.