Arch Linux

bionor

Member

Registered: 2020-08-23

Posts: 15

os-prober not detecting encrypted LUKS installation

Hello.

I'm having an issue as described above. At first I didn't mind because I hadn't unlocked that partition when I first installed grub on my new Arch installation as I figured I can just do that later, but even now when I have unlocked and mounted the partition it still doesn't seem to find it. I've searched around the webs for a while, but what I found either didn't apply to me, or it didn't work.

I'm not familiar with os-prober or how/where it looks for other installs, but my best guess so far is that it could perhaps be because the unlocked partition is mounted inside the root of my Arch and perhaps os-prober just doesn't look there beyond certain directories such as /boot etc, which makes sense to me.

The partition is mounted with

cryptsetup open /dev/nvme0n1p8 nvme0n1p8_crypto
mount /dev/mapper/nvme0n1p8_crypto /mnt

Another possibility is that my setup is potentially a bit messy at this point. This machine have gone through some changes over time where I've cloned the original SSD which contained a Windows installation and an Ubuntu installation and copied it over to an NVME disk when I upgraded it. I later on added a Kali installation to the NVME disk, so at that point I had a total of three OS's on the machine (Win @ nvme0n1p2, kali @ nvme0n1p8 and Ubuntu @ sdc). I then had to convert the old MBR-BIOS regime to the GTP/UEFI system for some reasons which then of course affected the /boot directories somewhat. Everything was still working at this point, for the most part, with the exception that when I for instance upgraded the kernel at my Ubuntu install, I noticed that nothing happened until I updated grub from the Kali installation which is the one I installed last and hence is the one that has the /boot which grub actually boots from. So then I realized that the multiboot environment isn't exactly set up perfectly.

I have now added Arch to the whole setup as well (@ nvme0n1p9). This time I made sure that the EFI partition (nvme0n1p1) is the one Arch mounts as it's boot partition.

The messy setup aside, I still believe it should be able to work. As a last resort, perhaps I could just add an entry for the missing Kali installation manually, but I'd prefer if I could fix it so it does it autonomously.

Is there a particular way I should mount the encrypted partition in order for os-prober to see it, or is it more likely that it has to with the way all the /boot directories are set up atm? I'm happy to provide any printouts of my setup should that help.

Last edited by bionor (2020-08-25 13:10:25)

bionor

Member

Registered: 2020-08-23

Posts: 15

Re: os-prober not detecting encrypted LUKS installation

I found the grub.cfg for the missing OS and managed to fix it by manually adding the menu entry to the current grub.cfg

Not the prettiest solution, but it works. That's how it is when one has such a messy setup I guess.

For future reference, what is the best practice regarding /boot and multiple operating systems? Is it better to have each OS have each their own /boot inside their own root?

GaKu999

Member

From: US/Eastern

Registered: 2020-06-21

Posts: 696

Re: os-prober not detecting encrypted LUKS installation

The best practice is the one you are comfortable with, and works of course...

My setup with GRUB2, a lone 64MB FAT12 ESP and each distro (Arch only for now...) living inside a LVM is quite weird and uncommon...
And I’m not using a /boot partition, each distro haves /boot as part of the / filesystem.

There’s a reason for /boot placement/existence related to 2TiB limitation for bootloading if I remember properly...probably will bite me later...maybe.

Since I handwrite my grub.cfg, you’ll need to use something confortable for you, if you rely on grub-mkconfig...

Best place for such knowledge is the wiki of course. They’ll probably covered that already.

Last edited by GaKu999 (2020-08-25 14:23:25)

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