Arch Linux

KylieGS

Member

Registered: 2018-02-19

Posts: 53

Non-standard grub config

I'm trying to get my head around how grub sources configs and things. And my lack of knoege has become clear when I try and do something non-standard.

As it stands my /boot partition for my desktop sits on a usb stick. The main disk is encrypted as a block device but that's not an issue. So I installed grub onto the USB stick as I normally would. However instead of running grub-mkconfig I added a menu entry:

 menuentry "Boot desktop" {
	search --set=root --fs-uuid ********-****-****-****-************
	echo "Loading Kernel"
	linux /vmlinuz-linux root=/dev/mapper/desktopSSD-root rw  quiet
	echo "Loading Initial RAMDisk"
	initrd /initramfs-linux.img
} 

With the uuid pointing to the partition on the usb where the kernal and initram are. (But then why does it work to use the /dev/mapper root as an argument to the kernal? I'm pretty sure the kernal can't decrypt the disk anyway, that's all hooks for the initram (right?). )

Right, so all's well and good. The system seems to source this just fine. I then set my laptop up in the same way. and go to add the menuentry but obviuosly it's not there because this is a different /boot (I keep them seperate so I can just but the partition in my fstab and update linux without having to fuss over which kernal the system is allowed to edit).

The new menuentry is simlar but with a different root and uuid.

So tbh I wasn't sure what to do and just copied the lot over and kept a duplicate on each partition but that's obviuosly ridiculous right? However if I edit the menu entry on on machine it seems to only effect that one machine. I want to put a recovery system on a third partition now but honestly I'm lost.

So where does grub source configs? How do I set this up to work reliably?

Last edited by KylieGS (2018-07-10 20:12:07)