Comment 1 for bug 2002160

This doesn't seem specific to minimal images, just related to old ubuntu versions.

cloud-init.user-data is a relatively recent config key. The version of LXD shipped with 18.04 (v3) didn't have it. Images of that release also don't have that config in their nocloud template.

However, older images support the "user.user-data", which still works with newer images (and will work as long as lxd supports it). So it's not a regression.

The question becomes if we should consider starting to add forward-compatible lxd config keys to old lxd images nocloud metadata templates. I anticipate regressions. And that's more of a feature request than a bug. Triaging as wishlist.

TLDR workaround, use "user.user-data"