Running Ubuntu full screen under Hyper V 2012

There is no way through the GUI to configure the screen resolution of an Ubuntu guest to run full screen when running under Hyper V 2012 (on Server 2012 / 2012 R2 or Windows 8 / 8.1).

One way to get Ubuntu running full screen is to hard-code the resolution of your monitor as a Linux kernel parameter. My monitor runs at 1680x1050, so I made the following changes to my Ubuntu 13.10 guest:

1. Edit the grub configuration file, for example:

   sudo vi /etc/default/grub

    
2. Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT, and add "video=hyperv_fb:1680x1050" (or your custom resolution) in between the quotes. For example: 

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=hyperv_fb:1680x1050"

3. Save and exit 
4. Run 

   sudo update-grub

5. Restart your computer

If you get an error dialog warning about not being able to apply the video mode when logging into the GUI, use the Ubuntu control panel to change the screen resolution to your chosen custom resolution.