Comment 14 for bug 1764314

We had a discussion on this:
I have to beg your pardon for all of the Ubuntu community, but we never intended to support write-managing through libvirt in Bionic. Libvirt iface-* never supported networkd or NetworkManager. To manage networks with different backends there is netplan.io.

Adding a dependency to ifupdown from netcf could hurt new installs of Bionic by pulling in ifupdown again - there are known issues and races around that that we want to avoid.
Upgraders have ifupdown around from their past anyway and new users “insisting” on the old use case can still install ifupdown on their own.

It is bad to not have the visibility of all devices in virsh iface-list and virt-manager and such, but since this is the case since at least Xenial and it never was an issue.

Compared to the alternatives - we didn’t come up with a way to fix it yet which would not carry a regression risk (or even regression fact) that would be too high. On balance it is not reasonable to be fixed at the moment. If that importance goes up what might come to my mind is a config option in libvirt where users can switch to udev - but that feature isn’t implemented in libvirt at all - so it would be a major effort not matching the severity of this IMHO.

Goin forward to Cosmic and beyond we will switch to the udev to fix the visibility

For all of the of the above I’ll have to set Bionic to Won’t Fix unless there is a change of severity due to for example more important use-cases we haven’t seen.

/me feels bad as Nicolas made a great and valid bug report, but for now this is the right choice