Comment 7 for bug 1764314

Networks are configured through net-* commands (and respective APIs) and they all work.
This is what is commonly used by libvirt users and solutions depending on libvirt.

The scope of iface-* commands is to manage the Host network interfaces.
This is not really what we'd want libvirt to do.
You can use networkd/NetworkManager directly and if you want a great one for all solution use https://netplan.io/ - but we don't really want libvirt "for that task".

I see that the virt-manager tab "Connection Details" -> "Network Interfaces" would become a read-only pane then. But considering how long it had partial content and set up things not 100% as they should be set up maybe it is even a fix to stop it from doing so.

I'll investigate the feasibility of the udev backend and if we can set that as the default.
With some luck we can keep netcf around for those who want to opt into the former behavior, but that has to be checked - and actually I'd vote for getting rid of it if that finds approval.

@Nicolas - did you have a specific use case in mind that fully relies on those things, because in discussion we cna't find one. Or did you just find it by checking out virt-manager in 18.04 but are not relying on it to be able to write interface configurations?