Nested VirtualBox virtual machine on a VirtualBox virtual machine

There can be reasons when we want to run a VirtualBox virtual machine on another VirtualBox virtual machine.

I am setting up a Windows virtual machine to interview job candidates and want to run a small Ubuntu virtual machine on the Windows virtual machine. It is not recommended for performance reasons, but I want to set up a base interview machine that I can wipe and recreate any time for the next candidate.

Besides the performance hit there is one more rule: the nested guest operating system needs to be 32 bit.

Even if you have a 64 bit workstation, and run a 64 bit guest operating system on it, the VirtualBox on the guest operating system can only host 32 bit guest-guest operating systems, because for a 64 bit operating system to run, the host machine needs to have the CPU Extension feature turned on. Currently only physical CPUs have the CPU Extension feature, so even a 64 bit guest virtual machine cannot provide it.

To set up the 32 bit nested virtual machine

1. Download ISO image of the 32 bit version of Ubuntu from http://releases.ubuntu.com/artful/
2. Start VirtualBox
3. Click the New icon to create a new virtual machine
4. Select Linux (32 bit)
5. Accept the default memory and hard drive settings

Start the virtual machine the first time

1. Select the new virtual machine
2. Click the Start button
3. Browse to the downloaded 32 bit Ubuntu ISO image
4. Follow the prompts to set up the operating system