On 07/25/2017 04:36 AM, 露露 wrote: 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. You need to define another network. http://libvirt.org/formatnetwork.html Michal