[solved]kvm on virtual server without vmx/svm @/proc/cpuinfo

Elleni · Veteran Joined: 23 May 2006 Posts: 1270

I want to run a VM on my hosted virtual server, and cat /proc/cpuinfo reads:

NeddySeagoon · Posted: Mon Nov 13, 2017 8:09 pm Post subject:

Elleni,

You want to run a Virtual Machine inside another virtual machine?

Yes its possible. I ran Virtualbox inside Virtualbox. It was a bit of an accident.
I used Virtualbox on my work laptop, which I used to image from time to time as a backup.

I also used to boot the image in Virtualbox on Gentoo. It was better than runnig the laptop itself.
One day I tried Virtualbox inside Virtualbox. It operated but performance was terrible.

Their is nothing special about virtualisation and Virtualbox, so I would expect other hypervisors to work too.
Working and working fast enough to be useful is two different things.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Elleni · Veteran Joined: 23 May 2006 Posts: 1270

Hello Neddy

Yes, the reason is just for testing purposes. I thought, as the virtual server is quite powerfull (it compiles much faster, than my old baremetal gentoo box with its core2duo processors), I thought it is worth a try to run kvm host on the vps. So I could try to do migration of a running vm from libvirt of my local box up to libvirt on host on the vps.

First I thought, it would not be possible at all, then read about nested vm, then read that kvm will need hardware virtualization (vmx or svm) support, and then finally found out, that vps is configured without those two flags needed to do kvm virtualization. :sad:

I opened a ticket and asked my hoster, if it would be possible to get vmx or svm support on that vps. I am also curious to see, how a vm in a vm would perform, as I read with vmx or svm it could be rather good.

NeddySeagoon · Posted: Mon Nov 13, 2017 9:34 pm Post subject:

Elleni,

Do you need full virtualisatien or will a chroot be good enough?
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Elleni · Veteran Joined: 23 May 2006 Posts: 1270

Well vps is X less, and I d like to have a vm with X inside it, which I can remotely access. Maybe paravirtualisation is the only other possibility to try as I imagine full virtualization without hardware virtualization extensions may be rather slow. Hm, a chroot ?

ct85711 · Veteran Joined: 27 Sep 2005 Posts: 1791

Having X is separate from a vm, in that the virtualization extensions have no effect on running X11. If you are wanting a GUI, you are dealing more on the graphics. As neddy mentioned, it is not generally recommended on running a VM inside a VM, but is possible (though some VM software can have issues with doing this). The biggest factor doing is, that on the host VM image, you need to be sure the virtualization extensions are also exposed (often the vm, is only sees a simulated cpu, not the actual one). Note, the virtualization extensions are not always required (depending on the vm software), but is helpful.

I am not familiar enough on qemu to know how that handles and what it needs. Though docker and lxc/lxd I don't think cares much if it is run inside a vm to matter much.

Elleni · Veteran Joined: 23 May 2006 Posts: 1270

Thanks for your informations guys

I will play around a bit, esp. with the idea of chrooting and thus eliminating the overhead of virtualization altogether as server is already a vm. So I will try to install another instance of Gentoo within the chroot jail - this time with X and some DE.

I will then access my vm as usual with ssh and then chroot to the jailed instance. I am courious to see, how then things like ip connectivity, X and so on will do within chrooted environment.

So I put this thread solved, not without thanking you again for your posts