Running Proxmox and VirtualBox side by side now possible ?

[Chentoa]

Just in case you missed it : a German company launched an open-source KVM-backend for VirtualBox

https://cyberus-technology.de/articles/vbox-kvm-public-release
https://github.com/cyberus-technology/virtualbox-kvm

So, it seems running Proxmox+VirtualBox at the same time should now be possible.
Didn't try it yet, though

 

[Kingneutron]

Virtualbox has some nice features (easy encryption of a VM, for one) but it's incapable of getting 10Gbit network speeds in a VM -- whereas Proxmox can do this.

PMVE is built on top of Debian so you could theoretically run both on the same host, but if you ran a GUI on the PM host it would take away resources for VMs / containers. VB headless is an option tho but in my experience you don't want to mix hypervisors on the same box.

I would advise installing a separate OS - dual boot with another Debian or Ubuntu, or test VB on another box with the same resources.

 

[LnxBil]

so you could theoretically run both on the same host

As far as I understand it, the OP wanted to state that it might now run side-by-side, whereas is was defenitely not possible to run the kvm and vbox kernel modules side-by-side before the german company switched the underlying hypervisor.