UML equivalent for one of the BSDs?

Question

On Linux there exists a thing called a User Mode Linux kernel, which is a kernel built in such a way that it will run as an ordinary, unprivileged user process (not even needing root). It's a cheap and easy virtualisation method that'll even run on non-Linux platforms (e.g. CoPilot is based around UML built for Windows).

Does such a thing exist for the BSD world? I don't mind which OS.

I've had a look myself but 'user mode bsd' is a completely ungoogleable term. I've discovered NetBSD rump kernels, but they seem to be solving a different problem --- it looks like it's not possible to run arbitrary process trees on them.

Answer 1

On FreeBSD you have jails. They basically are a (almost) no-overhead virtual machine running on the same kernel as the host.

Answer 2

The best true virtualisation tool in the NetBSD world is Xen.

It's not all that difficult to set up any more either. Don't get put off by the length and volume of information in the "how-to" -- the basics boil down to a few simple steps.

NetBSD/xen HowTo

In the FreeBSD world I've heard good things about The BSD Hypervisor

DragonFly BSD's vkernel is indeed similar to User-Mode-Linux, but from what I've heard it wouldn't be very suitable as a "cheap and easy" virtualisation method. It is actually intended for the same types of uses as NetBSD's rump kernels, though it does seem to go so far as supporting a full virtual OS environment. The performance will likely be pitiful though.

It probably wouldn't hurt to pester the VirtualBox folks about supporting VBox as an application on the BSDs too, but don't hold your breath waiting for it to happen.

Answer 3

NetBSD has usermode too. I don't know how to configure/build it.

Look : http://mail-index.netbsd.org/current-users/2015/02/06/msg026632.html

Answer 4

I think DragonFly BSD's vkernel is what you are looking for.