Grub as a stand alone
 

Hi

I would like to install grub2 as a standalone not connected to any OS.
Can I put it in an extended partition
It will have to boot multi distros with chainloading, I know this is setup in /etc/grub.d/40_custom so how would this work.
Finaly how would I update-grub when a distro updates or would that have to be done by hand?
Think I have covered everything

Unfortunately, you can't do that. For some strange reason I never could understand, Grub2 is an integrated part of the OS.
If you install Grub2 in one partition and then remove the distro, you have no control over your Grub2-installation.
This is why I'm still using old grub, I want one place to boot from. What I've done is install grub-legacy in one small partition, and use that for booting.

Probably because it was written by (predominantly) Debian/Ubuntu people that obviously have no concept of users doing what they want.
Placing files under /etc destroys plans like this.

I keep one installation (distro) per physical system so I have control of the boot environment whatever I do with the other distros. Can still be a challenge, but is manageable in my situation.

Edit: yes you can install to a logical partition (not the extended).

Hi syg00

That is how it is at the moment, I did mean logical I realised that after I posted.
Not sure I,m going to keep ubuntu tho.

Shouldn't matter. Any newer system can be the "control" system - simply allow it to install into the MBR.
The problem(s) come when other systems automatically over-write the MBR without you knowing - usually when they upgrade grub in their own environment. Generally pretty easy to fix.

The other OS are bsd,centos windows they dont use grub2 which I,m familer with and like the only reason I put ubuntu on was grub2 and I have used before.

As I said, no big deal if you replace Ubuntu with something else that uses grub2. These days they should all run os-prober - don't know if it'll find a BSD as I don't use it, but shouldn't be hard to fix - maybe keep your own .cfg on a USB key.