Comment 13 for bug 1737630

cloud-init supports rendering configuration for multiple different networking backends (netplan, ifupdown, sysconfig). Note that networkd is _not_ one of those backends (because it configures networkd via netplan), so cloud-init feels like the wrong place to be poking at networkd.

This feels like an image mastering issue to me. If you create an Ubuntu image that isn't configured to bring up networking, then it's not going to bring up networking. Perhaps I'm missing something here.