Using Grub For Several Distros

Ketje · 05-31-2005, 06:53 AM

I have 3 distros on 3 separate partitions and use Grub for them all. By modifying the Debian/Ubuntu menu.lst or Fedora grub.conf I can boot any distro I want. The problem comes when I update one distro with a new kernel (resulting in a new entry in the corresponding grub configuration file on its partition) that the new distro is not available in the grub menu from the other partitions. Is there any way (maybe using the chainloader) to select an load the grub boot-loader of one partition from the grub boot-loader of another partition such that I see all the possible kernel loads of each partition from their respective grubs?
I have tried laoding Stage1.5, Stage2 and grub itself but always get the error:
error 13: Invalid or unsupported executable format.

vharishankar · 05-31-2005, 06:58 AM

I don't understand why you need multiple grub config files.

Quote:

The problem comes when I update one distro with a new kernel (resulting in a new entry in the corresponding grub configuration file on its partition) that the new distro is not available in the grub menu from the other partitions.

Choose to install a single GRUB to MBR (from one distro) and then manually add the kernels to that distro's menu.lst file for other Linux partitions.

Easy as pie

Part of my manually edited menu.lst (Debian's grub)

Code:

title  Debian GNU/Linux, kernel 2.4.27-1-386 
root  (hd0,1)
kernel  /boot/vmlinuz-2.4.27-1-386 root=/dev/hda2 ro 
initrd  /boot/initrd.img-2.4.27-1-386
savedefault
boot

title  Debian GNU/Linux, kernel 2.4.27-1-386 (recovery mode)
root  (hd0,1)
kernel  /boot/vmlinuz-2.4.27-1-386 root=/dev/hda2 ro single
initrd  /boot/initrd.img-2.4.27-1-386
savedefault
boot

title Gentoo Linux, kernel 2.6.10
root (hd1,0)
kernel  /boot/kernel-2.6.10-gentoo-r6 root=/dev/hdb1 ro
savedefault
boot

title FreeBSD 5.3
root (hd1,2,a)
kernel /boot/loader

title  Windows 98
root  (hd0,0)
makeactive
chainloader +1

Ketje · 05-31-2005, 08:38 AM

When I update a distro to a new version it automatically updates the grub.conf or menu.lst on its own partition. That means the menu list on the other partition is out-of-date.

e.g. on Partition #1 (simplified):
root(hd0,0)
kenel a.1
initrd a.1

root (hd0,1)
kernel b.1
initrd b.1

root(hd0,2)
kernel c.1
initrd c.1

I select the latter (kernel c.1) and then decide to do an update of the kenel from c.1 to c.2.
This updates the grub.conf on the corresponding partition (#3), but my menu on partition #1 still has
the c.1 entry which I manually have to change to c.2 to load the new kenel.

vharishankar · 05-31-2005, 08:41 AM

How do you update a distro? Maybe there would be an option not to overwrite the grub in the MBR.

There can only be one grub in the MBR at any given time.

Ketje · 05-31-2005, 08:46 AM

Yes, I only load one grub and that is on a specific partition but if I get a kernel upate for another partition the new version is not in the menu list because it updates grub.conf (menu.lst) of its own partition.

oneandoneis2 · 05-31-2005, 08:52 AM

Create a 50MB partition, copy your kernels to it, and mount it as /boot on every one of your distros.

The problem will be gone forever, as there will only be one grub.conf file, instead of one per distro.