[libvirt-users] how libvirt create virbr0

[Michal Privoznik]

On 07/25/2017 04:36 AM, 露露 wrote:
> libvirt
> version: 3.4.0
> architecture: x86_64 ubuntu16.04-server
> hypervisor: kvm,qemu
> 
> 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.

This may be due to the libvirt built from source doesn't have the
correct prefix? I don't know how/whether ubuntu does it, but in many
distros I've seen that they install default libvirt network (virsh
net-dumpxml default) and also set it to autostart. Now, the configs for
libvirt networks, domains, etc. is stored under /etc/libvirt. But if you
build libvirt from sources and do not set --prefix, that libvirt will
look under /usr/local/etc/libvirt. And since there is no network config,
it doesn't start any. I should point out here that network should remain
running even if libvirtd is shut down. The reason for that is to
maintain connectivity for the domains.

> If I want create another virtual bridge ,How can I create and start the virtual bridge.

You need to define another network.

http://libvirt.org/formatnetwork.html

Michal