So, I recently embarked on a virtualization adventure that quickly turned into a troubleshooting marathon. Let me preface this by saying I’m a fan of experimentation, but sometimes, that experimentation leads you down a rabbit hole filled with ACPI errors, Grub rescue prompts, and the distinct smell of burning silicon (okay, maybe not the last one, but it felt like it).

The Original (Failed) Plan: VirtualBox Inception

My goal was simple: to run multipass inside a virtual machine. Why? Let’s just say it was for science! My initial setup looked like this:

  • Host OS: Linux Mint (because I like it!)
  • Hypervisor: VirtualBox (because it’s convenient)
  • Guest OS: Lubuntu (lightweight, seemed perfect)
  • The Goal: Run multipass inside the Lubuntu VM, leveraging Nested VT-x (the ability to virtualize within a virtual machine).

Sounds straightforward, right? Wrong.

I installed VirtualBox on my Mint host, spun up a Lubuntu VM, and then tried to enable Nested VT-x. That’s where the trouble started. Almost immediately, I ran into a cascade of errors, culminating in a corrupted Grub bootloader on my host machine! Yes, you read that right. My host OS was refusing to boot. I was staring into the abyss of the dreaded Grub rescue prompt.

The culprit? I suspect a combination of factors. Enabling Nested VT-x in VirtualBox can be finicky. It might be due to a BIOS ACPI conflict, or some other gremlin in the communication between the hypervisor and the hardware. Whatever it was, it trashed my Grub configuration.

The (Successful) Redemption: KVM to the Rescue

After a frantic recovery involving a live USB and some Grub surgery, I decided to take a different approach. I realized I was trying to force something that wasn’t working well. It was time to ditch VirtualBox for this particular task and embrace a more native Linux solution: KVM.

Here’s the setup that actually worked:

  • Host OS: Linux Mint (still rocking it!)
  • Hypervisor: KVM (via qemu/libvirt)
  • Guest OS: Ubuntu Server (command line all the way!)
  • The Goal: Run multipass inside the Ubuntu Server VM, leveraging Nested VT-x.

This time, the installation was much smoother. I installed Ubuntu Server, enabled Nested VT-x for the VM in virt-manager, and then installed multipass. Everything worked!

The Performance Difference is Real

But the real surprise wasn’t just that it worked; it was the performance. The KVM-based setup absolutely crushed the VirtualBox attempt. Things felt significantly faster and more responsive. It makes sense in retrospect. KVM is a Type 1 hypervisor, meaning it runs directly on the hardware, giving it much better access to resources compared to VirtualBox, which is a Type 2 hypervisor running on top of the host OS.

Key Takeaways and Lessons Learned

  • Nested VT-x with VirtualBox can be problematic: Be prepared for potential headaches, especially with more complex configurations.
  • KVM is a performance powerhouse (especially on Linux): If you’re on Linux and need robust virtualization, KVM is often the superior choice.
  • Simplify Your Setup: Avoid unnecessary layers of virtualization whenever possible.
  • Check your BIOS: Ensure VT-x/AMD-V is enabled in your BIOS settings. Also, updating your BIOS can resolve ACPI related issues.
  • Use Virtualization Management Tools: Tools like virt-manager or virsh give you fine-grained control over your VMs.

Conclusion

This experience taught me a valuable lesson about the nuances of virtualization. While VirtualBox is a great tool, it’s not always the best choice for every task, especially when you’re pushing the boundaries with features like Nested VT-x. KVM provided a much more stable and performant platform for running multipass in a virtualized environment. Now, back to my experiments (hopefully with fewer Grub emergencies this time!). Happy virtualizing!