[Pkg-libvirt-maintainers] Bug#565767: Bug#565767: libvirt-bin: VM doesn't work after upgrade: qemu: Could not initialize device 'tap'

[Guido Günther]

Hi Tino,
On Thu, Jan 28, 2010 at 07:15:13PM +0100, Tino Keitel wrote:
> On Thu, Jan 28, 2010 at 18:53:48 +0100, Guido Günther wrote:
> 
> [...]
> 
> > This won't help since this is being created from libvirtd which runs as
> > root anyway (assuming you're using qemu:///system). We'd need:
> > 
> > * the libvirtd log, please run libvirtd in debug mode e.g. as root:
> > 
> > LIBVIRT_DEBUG=1 /usr/sbin/libvirtd
> 
> Attached, see libvirtd.out.
> 
> 
> > 
> > * The command you use to start the vm
> 
> sudo /usr/bin/kvm -m 128 -name mguard1 -uuid 996e70dd-e5df-41e8-827f-34da1ee95f24 -monitor unix:/var/lib/libvirt/qemu/mguard1.monitor,server,nowait -boot c -drive file=/var/lib/libvirt/images/kvm-mguard1,if=ide,index=0,boot=on,format=raw -net nic,macaddr=52:54:00:13:a3:04,vlan=0,model=e1000,name=e1000.0 -net tap,ifname=m1d0,vlan=0,name=tap.0 -net nic,macaddr=52:54:00:3e:f8:a6,vlan=1,model=e1000,name=e1000.1 -net tap,ifname=m1d1,vlan=1,name=tap.1 -net nic,macaddr=52:54:00:77:bb:e7,vlan=2,model=e1000,name=e1000.2 -net tap,ifname=m1d2,vlan=2,name=tap.2 -net nic,macaddr=52:54:00:58:bd:c9,vlan=3,model=e1000,name=e1000.3 -net tap,ifname=m1d3,vlan=3,name=tap.3

I do see the problem now. You're not letting libvirtd setup your tap
devices but do this yourself using interface type ethernet instead of
network (which is totally valid of course). Could you try to rebuild
libvirt without --without-libcapng and see if this helps? You can
additionally drop the --with-qemu-user and --with-qemu-group options. 

I'll try to reproduce this with interface type=ethernet but this will
take some time.
Cheers,
 -- GUido