Debian – Unattended installation of Ubuntu from USB drive — Not mounted correctly

automated-installautomountdebianmountusb-boot

I'm doing an unattended installation of Ubuntu-14.04-server with a USB drive on different type of servers (HP Proliant ML110, ML310, ML350).

In some cases, the USB drive is incorrectly mounted on /media instead of /cdrom, making the installation process stop with the following message:

[ Detect and mount CD-ROM ]

Your installation CD-ROM couldn't be mounted. This probably means that the CD-ROM was not in the drive. If so you can insert it an try again.

I managed to identify some cases where this error occurs:

on the ML110 and ML310: when the hard drive is empty
on the ML350 Gen9: even if the hard drive is partitioned.

I think it comes from the debian-installer that, at an early stage of the installation, tries to mount a partition from the first drive on /media. And then mounts the USB drive in /cdrom.

In the above cases, the hard drive is detected later during the installation process, making the USB drive the first drive and therefore mounting it on /media and not on /cdrom.

For the persons for which a manual intervention is not a problem, I found a workaround that I will describe in an answer below. But for an unattended installation, this is not a solution.

Can we force the installer to mount the USB drive on a specific mont-point?

Best Answer

For the persons for which a manual intervention is not a problem, here is the simple procedure.

Open another terminal tty2 or tty3 by pressing alt+F2 or alt+F3 and press enter
Un-mount the USB drive from /media:

umount /media/
Identify the USB drive sdX in the device list (sda, sdb, sdc, …)

ls -l /sys/block/sd* | grep usb
Mount the USB drive to /cdrom

mount /dev/sdX /cdrom
Go back to the main terminal tty1 by pressing alt+F1 and press yes to retry mounting the "CD-ROM".

As mentioned in the question, this is a workaround which is not a solution for an unattended installation.

Related Solutions

Linux – Boot Debian Linux from image on external USB drive

Regarding the bootmanager: when using FAT as filesystem then syslinux would be one approach. Especially when booting from USB you might consider using grub for booting, as you'll be flexible with the grub shell (providing a nice tab-completion). To install grub you'd be running something like:

mount /dev/sdX /mnt/
grub-install --recheck --no-floppy --root-directory=/mnt /dev/sdX

and adjust /boot/grub/menu.lst accordingly.

Your bootloader has to load kernel and initrd. So those files have to be outside your debianroot.img (unless you're using the ISO approach and grub2 with its loopback option, see http://michael-prokop.at/blog/2009/05/25/boot-an-iso-via-grub2/) and need to be referenced/configured in your bootloader (being syslinux.cfg for syslinux, menu.lst for grub1 and grub.cfg for grub2). The following is an example menu.lst file used for the grml live system (http://grml.org/) generated by grml2usb (http://grml.org/grml2usb/):

# misc options:
timeout 30
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
foreground  = 000000
background  = FFCC33

title grml  - Default boot (using 1024x768 framebuffer)
kernel (hd0,0)/boot/release/grml/linux26 apm=power-off vga=791 quiet boot=live nomce live-media-path=/live/grml/ 
initrd (hd0,0)/boot/release/grml/initrd.gz

The initrd file has to locate the debianroot.img on your devices and loopback mount it then. Then it should change your root file system via e.g. pivot_root (see http://linux.die.net/man/8/pivot_root) to inside the mounted loopback file. You can find more details regarding the initrd process in Documentation/initrd.txt of the linux kernel sources: http://lxr.linux.no/linux/Documentation/initrd.txt

If you'd like to know how common live systems do this kind of stuff check out debian-live (http://debian-live.alioth.debian.org/) or grml-live (http://grml.org/grml-live/) in combination with live-initramfs (which does all the initrd/initramfs magic and is used in most Debian based live systems; http://packages.debian.org/sid/live-initramfs).

A different approach to your debianroot.img approach would be talking an existing Debian based Linux Live system providing so called "root persistency" (for example the official Debian-live project provides this as well as grml 2009.05 does).

Linux – CentOS Stop CD-ROM from mounting at boot

I was under the impression that was handled via hald.

Maybe not, but another option (presuming you don't need them), would be to just disable them via your server's BIOS. I've done that when I wanted to hold onto the drive, but not have it active in the system.

Best Answer

Related Solutions

Linux – Boot Debian Linux from image on external USB drive

Linux – CentOS Stop CD-ROM from mounting at boot

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