virtualbox.org

I've heard (but not verified) that it's possible to run VMWare ESXi *inside* of a VM. Is this possible with Microsoft's Hyper-V? Or will I tear a rift in the space-time continuum if I try this?

Background: I'm trying to learn Windows Server 2012 & R2 running on a virtual network with VirtualBox. Hyper-V is a technology that MS is pushing pretty hard, so it would be useful to learn how to configure and administer it, even if performance is abysmal.

EDIT: I did some additional research, and found that this feature is called "Nested virtualization" and it was *NOT* supported with 64-bit guests, at least as of Aug. 2014. Has anything changed? What's the difference between "nested virtualization" and "paravirtualization"?

Nested virtualization is not supported with Virtualbox.
Paravirtualization is something completely different.

Martin wrote:Nested virtualization is not supported with Virtualbox.
Paravirtualization is something completely different.

Yep, I got all excited when I saw "Hyper-V" in the paravirtualization option. Apparently that's something completely different.

Reading through the VirtualBox documentation it seems like paravirtualization is basically a way to let the guest OS know it's running in a virtual environment. I'm not sure what benefit that endows to the guest OS though.

imrazor wrote:it seems like paravirtualization is basically a way to let the guest OS know it's running in a virtual environment. I'm not sure what benefit that endows to the guest OS though.

Paravirtualization is much more efficient than simulating hardware. Essentially the VM can access host hardware without the normal VM performance penalty. The downside is that the guest OS needs drivers for a specific VM API (or in the VBox case, a compatible API).

You would not cause any damage if you tried to enable the Hyper-V feature in a server VM. Hyper-V requires hardware virtualization, and that is not passed through to the guest. It might even tell you that it installed because it can install the management tools even if it cannot run vms. That is what it does on a physical machine which does not have hardware virtualization enabled.