How to use ubuntu server full screen in virtualbox?

You can have the ubuntu server console in VirtualBox start at a resolution that your graphic card supports via the virtualbox environment.

Quick Steps

• Check the resolutions your graphic card supports via the VirtualBox Environment (VBE).You should be able to find that out by issuing the command 'vbeinfo' in the GRUB console (hit the C key when the GRUB boot menu shows up).

• Pick one resolution, then open '/etc/default/grub' (e.g. sudo vim /etc/default/grub) and change the line #GRUB_GFXMODE=640x480 to something like this GRUB_GFXMODE=1152x864 (where 1152x864 should be your custom resolution which is also supported by your graphic card).

• Now run these two commands one-by-one:

  sudo update-grub
  sudo reboot
  

You should now see your VM's console in the custom resolution that you just set.

(PS: As Javier Rivera said, full screen resolution may not be possible.)

As mentioned in Proper way to change terminal resolution in Ubuntu Server 13.04? you also need to set

GRUB_GFXPAYLOAD_LINUX=keep

in the /etc/default/grub file otherwise the resolution is only briefly used during boot

Other answers didn't work properly for me on Ubuntu 16.10 - e.g. resolution would be applied, but then reverted at various points later during boot. What did eventually work was the combination of the following three settings in /etc/default/grub:

GRUB_GFXMODE=1280x1024  # width x height required - see below
GRUB_CMDLINE_LINUX_DEFAULT="nomodeset"
GRUB_GFXPAYLOAD_LINUX=keep

Followed by running:

sudo update-grub
sudo reboot

NOTE 1: Supported resolutions can be identified from within grub. Hit C at the grub prompt, then type:

set pager=1    (To enable paging of long vbeinfo output)
vbeinfo
reboot         (When done)

When selecting a resolution, width x height is sufficient (unless you specifically care about setting colour depth too).

Note 2: If you don't see the GRUB menu, hold Shift while booting.