GRUB2 multi-boot with one boot partition

Question

i'm trying to make a multi-boot disk (5 linux distros) with only one /boot partition. Problem is that the guy before me that made this disk didn't bother to create that separate boot partition, so i created one at the end of the disk, but now i cannot edit the grub menu from other distros except the last one i installed. I assume i need to point all the distros to that one /boot partition, but i have some questions; 1 - can/should I put all the kernels for the different distros in that one partition, can i separate them in folders? 2 - how do i point each distro to that /boot partition?

The distros i have installed are as follows sda1 RHEL 6.7 sda2 RHEL 7.0 sda3 RHEL 7.1 sda4 extended partition sda5 SUSE 12 sda6 Fedora 22 sda7 Swap sda8 /boot

Answer 1

You can go that hard route, or you can achieve multi-boot with one boot partition with the following simple steps,

1. Make each OS, your sda1 RHEL 6.7 sda2 RHEL 7.0 sda3 RHEL 7.1 sda5 SUSE 12 sda6 Fedora, etc, to boot on their own from their own partition
2. Use GRUB2 Chainloader to boot them individually. Ref: here, here and here.

Here is an example:

menuentry "Chainload to OS in /dev/sda9" {
        set root=(hd0,9)
        chainloader +1
}

OR

menuentry "Chainload to DOS in /dev/sda9" {
        set root='(hd0,msdos9)'
        chainloader +1  
}