Comment 4 for bug 2004131

Yes, I've put this into user.vendor-data.

Since that file successfully arrives in
/var/lib/cloud/instances/7dfe250e-91a6-4391-a3c6-ae2b4fc1ffee/vendor-cloud-config.txt

and other options in this file are successfully executed, I did not see a problem in putting it into user.vendor-data.

I currently don't know how to use cloud-init.network-config, since the link you've mentioned does not specify a syntax for a search path, and it does not look like netplan syntax.

But what if I use cloud-init with Ubuntu's cloud image or server installation, where there is no LXD around. Would it be impossible to set a search path with cloud-init then?