Linux – With Centos 7 as a Virtualbox guest on a Mac Host, how can I change the screen resolution of the console / command line

centosgrublinuxvirtualbox

I am using the minimum install of CentOS 7 with command line access only (no graphic support installed).

After spending hours reading online about editing grub files, installing guest additions, and setting VB options, absolutely nothing is working for me.

First, guest additions is installed. Secondly, the only grub file I have is /boot/grub2/grub.cfg, and it says not to edit it as it's dynamically generated. Finally, editing the Display under VB's > Machine > settings to automatic, none, or hint with the resolution I want does not make a difference.

Step by step, what exactly do I have to do in order to get my screen resolution to be larger than 640 x 400 as well as provide for a buffer (currently there is no buffer)?

Best Answer

CentOS 7 still uses the deprecated vga parameter. You wanted step-by-step, you get it:

Make yourself root: sudo su
vi /etc/default/grub
In Vi, press i or Insert-key on your keyboard to enter the edit mode.
Add vga=792 inside the "-quotes for GRUB_CMDLINE_LINUX, f.ex. GRUB_CMDLINE_LINUX="crashkernel=auto rhgb quiet vga=792"
Press Esc and type :wq and hit Enter to save and exit Vi.
grub2-mkconfig -o /boot/grub2/grub.cfg
reboot

This procedure applies not just Mac, but all host operating systems running Virtualbox: Windows, Linux.

@garethTheRed's answer might work in some versions of some Linux distros, but the trick is to find the correct parameters for your environment. At least with some Red Hat distros you need to fall back to old, deprecated habits.

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If you are accessing the Apache HTTP Server welcome page using localhost and not the IP address, then it is possible that dhcpcd is not running. Have you verified that sshd is running?

MacOS – Change Guest Screen Resolution in VirtualBox

I am using VirtualBox under Ubuntu Linux, and a Mac OSX (Mountain Lion) as guest OS.

For me, the full resolution started working when I did all of the following:

0) Install MultiBeast 4, making sure that the system boots from the virtual hard disk rather than from any booting CD. I followed the instructions here:

http://www.macbreaker.com/2012/07/mountain-lion-virtualbox.html

However, at the end of the procedure I did not have the full resolution, which for me must be 1920x1080x32.

1) In the virtual machine, edit these PLIST files,

sudo pico /Extra/com.apple.boot.plist/Library/Preferences/SystemConfiguration/com.apple.Boot.plist

In this file, inside <dict>...</dict>, insert:

<key>Graphics Mode</key>
<string>1920x1080x32</string>
<key>Kernel Flags</key>
<string>"Graphics Mode"="1920x1080x32"</string>

sudo pico /Extra/com.chameleon.Boot.plist

In this file, inside <dict>...</dict>, insert:

<key>GraphicsEnabler</key>
<string>y</string>
<key>Graphics Mode</key>
<string>1920x1080x32</string>
<key>Kernel Flags</key>
<string>npci=0x3000 darkwake=0 "Graphics Mode"="1920x1080x32"</string>

I noticed that I already had some "kernel flags", so I just added another one for "Graphics Mode". Also note that "Graphics Mode" has a space inside it.

2) Shutdown the virtual machine and do the commands

vboxmanage setextradata "MAC OS X" "CustomVideoMode1" "1360x768x32"
vboxmanage setextradata "MAC OS X" "GUI/CustomVideoMode1" "1360x768x32
VBoxManage setextradata MountLion VBoxInternal2/EfiGopMode 3

After this, the virtual machine boots with full resolution.

Now, this might be overkill, and the result could be achieved perhaps with fewer options, but I tried various things until it started working.

Best Answer

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