subiquity installer support for configs from dhcp vendor class option

[Bpkroth]

With the debian-installer it was possible to provide a tftp:// url for a basic preseed config to download via dhcp response options:

https://help.ubuntu.com/lts/installation-guide/amd64/apbs02.html#preseed-dhcp

This doesn't seem possible in subiquity at the moment.
If it is, and I missed it, can someone please point me at the docs?
If not, can this feature be added? It would be particularly useful in a cloud-init nocloud setup for as a preseeding replacement for local network auto-installers.

Thanks!

[Michael Hudson-Doyle (mwhudson)]

This is not possible today, afaik. TBH, I'm not entirely sure I see the advantage -- it means you don't have to run a http server as well as a tftp server I guess? If that's the case I suppose we could teach cloud-init to handle tftp seed URLs (I also don't see how passing the filename to download via DHCP is useful in a netboot when you control the kernel command line to the booting system anyway but perhaps I'm being dense)

[Bpkroth (bpkroth)]

TFTP was just an example. HTTP would be fine too. The point was just to allow the installer to request preseed information early in the process via DHCP.
This was for a poor-man's partially automated boot setup (not full PXE).
Think of using a USB drive (or .iso for a VM) to boot from the "standard installer", but then preseed most/all of the the usual installer questions questions that don't vary across versions or that may be specific to that network location (e.g. apt proxy info).
Yes, probably a limited use case, but still a nice time saver.
In the past this was easier than rerolling an installer image to have the files embedded.
Now I guess one can prep a separate USB drive with an appropriate label, which works well enough.