[libvirt-users] Using Openvswitch and qemu:///session

[Predrag Ivanovic]

On Wed, 23 Mar 2016 13:07:12 -0400
Laine Stump wrote:

>What you're trying to do isn't supported and won't work. the 
>qemu:///session libvirtd runs as a normal user, and doesn't have the 
>necessary permissions to create tap devices or connect them to either 
>Linux host bridges or OVS bridges. qemu added the "qemu-bridge-helper" 
>which is a suid binary that will create a tap device and connect it to 
>the named Linux host bridge, and the person who wrote that helper also 
>made a patch to libvirt to automatically call the qemu-bridge-helper 
>when a request is made in a qemu:///session guest to connect to a 
>bridge. Unfortunately, qemu-bridge-helper only knows how to connect to 
>standard Linux host bridges, it knows nothing about OVS.

Thank you, that answers my questions pretty thoroughly :)

>I believe there is an OVS compatibility module that makes the ioctl used 
>to connect a tap device to a host bridge also work for OVS bridges. You 
>may want to look into that.
<snip>

Br-compat module was removed from OVS few releases ago, IIRC, since 
libvirt and KVM/QEMU can use Openvswitch bridges natively now.
And it works just fine, just not for my use case :)

Thanks again for the information on inner workings of user session, now I know what I have to do.
Luckily, I don't have that much domains to migrate.

Pedja