virtualbox.org

I'm trying to setup a solution running both my Host and Guest OS in parallel - with the latter operating in the background. I've been able to achieve this on other machines, but for this particular deployment I need both to operate concurrently (in previous deployments one is a virtual mail server and so SSH and VNC access suffice) - for this one I'm wanting both to operate in the foreground such that at the login screen the user can press a given key combination and switch to/ from the guest/ host OS. I've seen this done before with Microsoft Virtualisation solutions, but not with VirtualBox - however being more familiar with the latter I was hoping this was possible and I had just overlooked something in the configuration and setup.

I'm grateful for any help/ guidance anyone can offer on whether or not this is possible, and if so how to achieve it.

Well, running host and guest in parallel is a given, since the VM can't run without the host. However, reading between the terminology issues I think what you're looking for is headless mode. VBox has supported headless VMs for a long time, but in fact VirtualBox v5 did recently make it easier to launch them from the GUI.

Thanks for your reply mpack - I'm new to Virtualisation and so I'm not great on the terminology, I can run VMs headless (it's how I'm running my mail server), but what I'm wanting to be able to do is access the headless VM on the host and interact with it - without logging on to the host. So for instance when my users see the Windows 10 login screen they could press a given key combination to switch the guest (virtual) Ubuntu machine into the foreground and login to it directly (so without needing to login to the host and then VNC into the VM).

Oh, ok. You're asking about running the VM as a service. That's a very platform specific feature, but there is unofficial support for it: see the VBoxVMService sticky topics at the top of this forum.

when my users see the Windows 10 login screen they could press a given key combination to switch the guest (virtual) Ubuntu machine into the foreground and login to it directly (so without needing to login to the host and then VNC into the VM).

The above quote, I think, is asking for something that doesn't exist yet in Virtualbox. The usual Windows OS's do not have any way to access the RD/VNC client while on the lock screen without having logged in first, unless something special is added to the host OS. Virtualbox does not provide anything to make the host OS allow doing anything else other than logging in while on the lock screen.