[CentOS] Installing from USB flash drive

[Todd Denniston]

Bowie Bailey wrote, On 05/26/2010 10:59 AM:
> I successfully created an install media on a USB flash drive, but now I
> have a minor problem installing from it.  Whenever I run the installer,
> it insists on installing grub on /dev/sdb (the flash drive) rather than
> /dev/sda (the hard drive where I'm installing everything).
> 
> Is there a way to convince the installer to put grub in the right
> place?  

If you are installing from a kickstart, or at least preparing the install using KS, yes.
In my case it was easy, target of install was an IDE and source usb drive was detected as SCSI, in
the kickstart file I was using I set:
bootloader --driveorder=hda,sda
granted I put that in a file that kickstart included, by building the file in the %pre section of
the kickstart, i.e., I ran some detection routines to be sure of what I was putting in there.


however for yours, because both show up as sd? you will need to be aware of BIOS/kernel detection
order.  The detection order may be different between booting the install media bootloader and
booting the final system grub.

Assuming you are using a kickstart file, you could probably program the %pre to figure out which is
which by looking for a known UUID of the USB flash or its file system label and tell grub use
anything else it finds first.


I believe the final file you would need to look at is /boot/grub/device.map
grub and grub-install take options for this file.

> Should I just tell it not to install grub and then do a
> grub-install from a rescue prompt afterwards?
> 

painful, but possible.

Hopefully enough clues to be helpful.
-- 
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter