Comment 42 for bug 1271144

I've found a workaround for the issue to let me launch lxc containers via juju

After the first container fails to launch, ssh to the hypervisor
edit /var/lib/lxc/juju-trusty-lxc-template/config
change br0 -> lxcbr0

After editing the template config all subsequent lxc containers will launch via juju