Recent ubuntu desktop isos require extra boot args

[slowpeek]

Since 21.10 ubuntu live-server iso uses multi-layered squashes (compare contents of /casper/ before and after 21.10). It doesnt affect anything because the images can boot without any kernel args. Ubuntu desktop uses the same multi-layered scheme since 23.04 but without explicit layerfs-path=minimal.standard.live.squashfs kernel arg it does not boot as supposed.

Ubuntu flavours are likely to move towards the new installer as well, but not there yet (aside for Budgie) as of release 23.10.

Btw with 23.04 they've introduced desktop-legacy images which are based on the old installer.

[thias]

I'm super confused with all this :sweat_smile: Recent desktop? But live-server? Doesn't affect anything.... so nothing to do? What does "do not boot as supposed" actually mean... working partially?

I'm asking because I can boot both 22.04.3 and 23.10.1 desktop-amd64 just fine once shrunk to below 4GB. Am I missing something?

[slowpeek]

There are three kinds of ubuntu images able to boot from loop:

• live-server. New multi-layered installer since 21.10. It can boot without any kernel args, be it either the old installer or the new one.
• desktop. New multi-layered installer since 23.04. My bad, they've fixed it somewhere during the dev cycle of 23.10 (I tried last time on some daily), but 23.04 still cant boot without layerfs-path=minimal.standard.live.squashfs. Try booting 23.04 in a vm, press "e" on the boot line in grub and delete that piece. Press C-x to proceed. You'll see what I meant saying "it does not boot as supposed". It just stops at the blue screen [1].
• desktop-legacy. Since 23.04, uses the old installer. Nothing to say here

22.04.3 is out of question because it was 23.04 the turning point

[1]

[slowpeek]

Okay, I've found my discussion on the matter in the maillist: https://lists.ubuntu.com/archives/ubuntu-devel-discuss/2023-June/019562.html

Looking into initrd of 23.10 now I see they've added conf/conf.d/default-layer.conf with the same content as on live-server:

LAYERFS_PATH=minimal.standard.live.squashfs

That's why 23.10 desktop, as you see it now, can boot without layerfs-path=minimal.standard.live.squashfs. But 23.04 lacks that and it never gonna be fixed. So GLIM cant correctly boot 23.04 desktop.

[thias]

Well, since 23.04 isn't an LTS release and 23.10 is out... is this a problem that needs to be addressed? I see a few different solutions:

1. Do nothing (my personal choice :smile:)
2. Switch to using the loopback conf for all Ubuntu
3. Introduce some regexp conditional

[slowpeek]

I'm just "reporting a bug" here! It is up to you