Grub and os-prober option (for dual boot)

[Saladin1812]

Currently this installer has systemd-boot. However grub has more options and also has support for os-prober (as an optional dependency) to detect other OS installed and dual boot which is a case for many users.

1. Adding option to use grub instead of systemd-boot will also help in solving Legacy support: MBR with Grub #42

2. Dual boot support in the grub menu (grub2-mkconfig will add entries for other operating systems it can find. That will be done based on the output of the os-prober tool. ) os-prober is an optional dependency for grub which fits in this case.

[Torxed]

Thank you for the suggestion, this is implemented in #113 and a duplicate of #42.
The current roadmap/plan is to implement this into v2.2.0 which is due in roughly a month.

The next release which should be coming in two weeks time will focus on bug fixes and some quality of life changes to the current code without adding to much new complexity. But it's coming, so hang tight! :)

[Saladin1812]

@Torxed there is nothing about os-prober. I opened the issue for dual boot support as well. It is an optional dependency for grub.

[Foxboron]

With the recent set of CVEs for grub os-prober is going to be disabled by default from 2.06 and on. It shouldn't be used with archinstall and people ought to figure out a better way to support dual boot sadly.

[Torxed]

I'm currently designing some new API calls that will allow us to detect other installations some what reliably.
This is done so that we can detect other installations across disks and not re-create the /boot partition if there's on available with enough space left over for our boot binaries.

Would this work as a workaround @jatin-cbs? It's not os-prober, but it's similar and will be an API call in this library.
Which the guided installer can use in-place of os-prober with either grub or systemd.

[Torxed]

I've done some extensive testing on the dual-boot support and mainly because #381.
As it stands currently, there's a regression bug that causes formatting to be executed twice for some reason (still investigating why) due to a regression bug #435, the first one behaves as expected, but the second formatting ignores any safety flags and safety checks - which means dual-boot is currently broken.

Unless you use "Use /mnt as is" option, all other options including "keep partitions layout" are currently broken in terms of dual-boot support. Hopefully fixed in #434!

[Torxed]

Would it be possible to install os-prober before we install grub via arch-chroot to detect other operating system and let grub-mkconfig detect it, and before we exit the installer/live ISO we uninstall it so that it doesn't remain and cause security issues?

If os-proper is required constantly, then we have an issue and I'll close this as wontfix

[Torxed]

Regarding the security concern, here's more information on it: https://lists.ubuntu.com/archives/ubuntu-devel/2021-December/041769.html (and a reddit conversation: https://www.reddit.com/r/linux/comments/rklytt/osprober_is_disabled_in_grub_206_and_where_to_go/)