KubeVirt with libvirt 9.0.0: Requested operation is not valid: The tap0 interface already exists

[Vasily Ulyanov]

Hi All,

I am now trying to run our downstream KubeVirt build with a recent libvirt 9.0.0
and I see a problem that libvirt refuses to start a VM if it is configured to
use a pre-created tap device:

  virError(Code=55, Domain=0, Message='Requested operation is not valid: The
tap0 interface already exists')

After looking at the git history I found the bellow commit [1] which explicitly
forbids such a usecase. This basically breaks KubeVirt since libvirt there runs
unprivileged and can only use the existing tap's.

I haven't yet look deeper into the original issue linked to the commit. Just
wanted to raise this here first. Perhaps someone can provide feedback on that.
What about some alternative approach instead? Or maybe it was discussed already...

BTW, I tested with the reverted commit and it was successful.

[1]
https://gitlab.com/libvirt/libvirt/-/commit/a2ae3d299cf9c5ada8aa42ec4271748eb479dc27

-- 
Vasily Ulyanov <vulyanov at suse.de>
Software Engineer, SUSE Labs Core