KVM VMs with virt-manager on openSUSE

I quite like virtual machines because I get to mess up with other systems without affecting my primary one. There are different virtualization technologies, I mostly used VirtualBox before, one of which is KVM.

KVM is basically a type of a hypervisor. It’s a different piece of technology than what VirtualBox provides. I won’t pretend to know many details, so if you need to know exactly how they differ, look it up.

virt-manager is a frontend for managing virtual machines via libvirt, and it mostly focuses on those KVM virtual machines. This is how the outcome looks with some running virtual machines:

virt-manager with Ubuntu and Debian running

I want to share a quick tutorial how to set this up on openSUSE (although it will likely be similar on other Linux distributions).

If I remember correctly, there are two packages that need to be installed (plus their dependencies, but zypper can take of it):

$ sudo zypper install libvirt virt-manager

You also need to have kvm kernel module (I think that’s already included in openSUSE):

$ lsmod | grep kvm
kvm_intel             385024  0
kvm                  1114112  1 kvm_intel
irqbypass              16384  1 kvm

If you want to use a non-root user, you need to add your unprivileged user to a libvirt group:

$ sudo usermod -aG libvirt pavel
$ grep libvirt /etc/group
libvirt:x:108:pavel

You also need to start libvirtd.service:

$ sudo systemctl start libvirtd.service

After that, you should be able to use virt-manager.

There’s, however, one caveat. Let’s say you have an iso file somewhere in your /home directory and you have 700 permissions on the home dir:

$ la
total 0
dr-xr-xr-x 1 root  root    10 Sep 10 22:35 .
drwxr-xr-x 1 root  root   166 Sep 22 20:36 ..
drwx------ 1 pavel pavel 1190 Oct  6 20:15 pavel

Then you will see the following error in virt-manager when setting up your VM:

Missing permissions

Clicking yes will pretty much solve it. The solution is to add ACL to the home directory for qemu user:

$ sudo setfacl -m u:qemu:x pavel/
$ getfacl pavel/
# file: pavel/
# owner: pavel
# group: pavel
user::rwx
user:qemu:--x
group::---
mask::--x
other::---

Execution permission on the home dir should be enough.

You can change the permissions in a different way (e.g. adding x to other) but that’s probably too much, ACL is probably a better solution here.

What also happens is that your iso file will change the owner when used for a VM in this way:

$ la
total 391184
drwxr-xr-x 1 pavel pavel       112 Oct  6 19:22 .
drwxr-xr-x 1 pavel pavel       222 Oct  6 19:20 ..
-rw-r--r-- 1 qemu  qemu  400556032 Oct  6 19:21 debian-11.5.0-amd64-netinst.iso

That should be all important that’s needed to set up this virtualization technology. Now you can install various OS and enjoy them as virtual machines.