Enabling /dev/fb0 on a CentOS 7 virtual machines?

Question

Recently ran into a situation where I need to install headless TeamViewer on a CentOS 7 server on Linode. This requires /dev/fb0 in order to function.

So far it has not been clear on how to enable the framebuffer (/dev/fb0). What do we need to do to install kernel support for a virtual machine?

Answer 1

I know this is old question, but still valid. In order to have /dev/fb0 you need to have the frame-buffer enabled in your kernel.

To check you can grep it from kernel configuration (from currently running grep CONFIG_FB_ /boot/config-3.10.0-693.17.1.el7.x86_64

For virtual environment you probably need VESA enabled so you add grep VESA and you should get the following output:

CONFIG_FB_BOOT_VESA_SUPPORT=y
# CONFIG_FB_UVESA is not set
CONFIG_FB_VESA=y

If you have this configured you will see the device /dev/fb0

Note: For older kernels like 4.9 you may need to add vga=0x317 in the command-line.

Answer 2

This works for me.

Perform steps as root:

1. systemctl set-default multi-user.target

2. append vga=0x317 to GRUB_CMDLINE_LINUX line in /etc/default/grub.conf

3. grub2-mkconfig -o /boot/grub2/grub.cfg

4. add the user to the 'video' group in /etc/group

   video:x:39:mario
   

5. reboot

Perform as user:

6. id

   uid=1000(mario) gid=1000(mario) groups=1000(mario),39(video)
   

ensure in video group (if not yet rebooted, log out and back in)