HowTo: VirtualBox on Debian Squeeze (Testing / Sid)

VirtualBox is the great, Free Software virtual machine software which compares to VMware and others. Unlike the closed-source competitors, VirtualBox has the needed source code 'kernel headers' which allow it to hook into your Linux kernel and do its networking setup, etc.

With a rolling-release distribution (which makes new software available as it gets released) such as Debian Testing or Debian Sid ('Unstable'), new kernels mean that the older apps and drivers which hook into the kernel no longer work. For example, if you have run a working VirtualBox virtual machine in the past but get errors like the following image, there is a good chance that the kernel has changed and you need to recompile the modules (drivers):

Debian has a great tool called "Module Assistant" which easily compiles needed modules (drivers) for various applications, including VirtualBox and some wireless network drivers.

To run VirutalBox successfully, make sure that you have 'module-assistant' and 'virtualbox-ose' installed, and optionally 'virtualbox-ose-qt' if you prefer a more KDE-like graphical interface.

Once those are installed you'll need to work at a command line. As root (or as a regular user with 'sudo' capabilities) run at the command prompt:

shell$ sudo m-a prepare

to get Module Assistant prepared with whatever it needs; likely it will download some kernel headers if you've not used Module Assistant before. Then we're going to 'auto install' (a-i) VirtualBox with Module Assistant:

shell$ sudo m-a a-i virtualbox-ose-source

You'll see some screens like this as Module Assistant is doing its work:

Once that is done, we'll need to load (modprobe) the kernel modules (drivers) that VirtualBox uses; you may want to add these modules to the file at /etc/modules so that they auto load at boot time. Note that because I had the older kernel modules loaded, I am going to remove (-r) them first, and then load in the newly built modules:

shell$ sudo modprobe -r vboxdrv
shell$ sudo modprobe -r vboxnetflt
shell$ sudo modprobe vboxdrv
shell$ sudo modprobe vboxnetflt

In this screenshot, we're getting warnings about an unrelated config file so we're going to ignore it as you may not have these issues on your own setup.

Now, VirtualBox is using the needed kernel modules for its current kernel and VirtualBox, and I am able to load my virtual machines again.

Happy VM'ing!