Yeah our security people got a bit over zealous. That's being rectified.
>You really need to look at /var/log/libvirt/lxc/dwj-hfax-dev.log
> TL;DR: My container is configured to use "br0" for its networking. "br0"
> exists totally inside my linux server - it is NOT bound to any physical NIC.
> "br0" is used for most of my QEMU and LXC VMs. libvirt is reporting that it
> cannot find device "veth1". All of my Gentoo packages are up-to-date.
>
> Digging through my logs (/var/log/libvirt/libvirt.log), I see that I last
> successfully booted this LXC container on 2013-07-22, with libvirt reporting
> version "1.1.0".
>
> Thoughts?
A suggestion would be to make sure that you have all the necessary
kernel options enabled. You can check with: ebuild
/usr/portage/app-emulation/libvirt/libvirt-1.1.2-r1.ebuild setup clean