libvirt<br>version: 3.4.0<br>architecture: x86_64 ubuntu16.04-server<br>hypervisor: kvm,qemu<br><br>when install libvirt from ubuntu distribution deb install libvirt, a virtual bridge virbr0 will be create . But when I build libvirt from souce code, how can I create a virbr0.<br>If I want create another virtual bridge ,How can I create and start the virtual bridge.<br>Thanks<br>