Installing Ubuntu 8.10 on a USB Drive with Debootstrap ¶

Contents

We will install Ubuntu on a USB drive without leaving our current Ubuntu installation.

My USB drive is /dev/sde and I create the chroot directory at /tmp/target. Have fun and good luck!

Your Skills ¶

You can partition a hard drive and
you can install packages and
you like the command line.

Prerequisites ¶

Get debootstrap (see Wajig (Package Management)):

wajig install debootstrap

Get admin rights to eliminate the need of typing sudo before every command:

sudo bash

Formatting ¶

Plain ext2 Boot Partition ¶

/boot should be a regular ext2 file system:

mke2fs -L boot /dev/sde1

Root, Swap, Home ¶

Any file system will do:

mkfs.ext3 -L root /dev/sde2
mkswap -L swap /dev/sde3
mkfs.ext3 -L home /dev/sde4

Tune2fs ¶

You could disable file system checks if you wanted to:

tune2fs -c 0 -i 0 /dev/sde1
tune2fs -c 0 -i 0 /dev/sde2
tune2fs -c 0 -i 0 /dev/sde4

Check Partitions ¶

fdisk -l /dev/sde

Mounting and Unmounting ¶

Create and run the Bash script mountall:

cat > mountall << EOF
mkdir -p /tmp/target/
mount /dev/sde2 /tmp/target/

mkdir -p /tmp/target/boot
mount /dev/sde1 /tmp/target/boot

mkdir -p /tmp/target/home
mount /dev/sde4 /tmp/target/home

mkdir /tmp/target/{proc,dev,sys}
mount -t proc proc /tmp/target/proc  # for bash completion
mount --bind /dev /tmp/target/dev
mount -t sysfs sysfs /tmp/target/sys
EOF

chmod +x mountall
./mountall

Create the Bash script umountall for later use:

cat > umountall << EOF
umount /tmp/target/proc  # for bash completion
umount /tmp/target/dev
umount /tmp/target/sys

umount /tmp/target/home
umount /tmp/target/boot
umount /tmp/target/
EOF

chmod +x umountall

Check that everything is mounted:

mount | grep /dev/sde

It is important to choose the right architecture in the next step. You probably want i386 or amd64. For a full list of supported architectures see http://archive.ubuntu.com/ubuntu/dists/jaunty/Release

New Hostname ¶

new_hostname=port
cat > /tmp/target/etc/hostname << EOF
$new_hostname
EOF
cat > /tmp/target/etc/hosts <<EOF
127.0.0.1       localhost
127.0.0.1       $new_hostname
EOF

Fstab ¶

Let’s get uuids and check them:

boot_uuid=$(vol_id /dev/sde1 | grep UUID= | cut -d= -f2)
root_uuid=$(vol_id /dev/sde2 | grep UUID= | cut -d= -f2)
home_uuid=$(vol_id /dev/sde4 | grep UUID= | cut -d= -f2)

echo $boot_uuid
echo $root_uuid
echo $home_uuid

fstab (the indentation will be proper after uuid substitution):

cat > /tmp/target/etc/fstab <<EOF
# device                                    mount   type options freq passno
UUID=$root_uuid   /       ext3 defaults,errors=remount-ro 0 1
UUID=$boot_uuid   /boot   ext2 defaults   0 1
UUID=$home_uuid   /home   ext3 defaults   0 0
EOF

Root UUID ¶

We’ll need root_uuid in the chroot environment:

mkdir -p /tmp/target/tmp
echo $root_uuid > /tmp/target/tmp/root_uuid

Chrooting ¶

chroot /tmp/target

Set the time zone and update the system (ignore the perl locale warnings):

cp /usr/share/zoneinfo/Europe/Berlin /etc/localtime

# add universe repository for wajig and python-optcomplete
echo `cat /etc/apt/sources.list` universe > /etc/apt/sources.list

apt-get update
apt-get dist-upgrade

Install the kernel, GRUB, completion tools and the terminal mouse server:

apt-get install -y\
    initramfs-tools\
    grub

apt-get install -y\
    linux-image-generic\
    vim bash-completion wajig python-optcomplete gpm

Enable root login:

passwd

Configuring the Boot Loader ¶

Remember the uuid of / (select with mouse). That’s why we copied it in Root UUID:

cat /tmp/root_uuid

Let update-grub create a menu.lst, then customize it:

mkdir /boot/grub  # else, update-grub won't create /boot/grub/menu.lst
update-grub
vim /boot/grub/menu.lst

Uncomment and edit:

timeout     9

Comment this line:

#hiddenmenu

Uncomment and edit:

color green/black black/green

Do not uncomment, but edit the following:

kopt=root=UUID=
alternative=false
defoptions=vga=791
updatedefaultentry=true

Exit the chroot:

exit

Making It Bootable ¶

MBR:

grub-install --root-directory=/tmp/target --no-floppy --recheck /dev/sde

You can remove all drives except (hd0) from /tmp/target/boot/grub/device.map.

Unmount:

./umountall

That’s it! Exit the “sudo bash”:

exit

Troubleshooting ¶

GRUB ¶

15 : File not found ¶

Check if vmlinuz-<kernel-version> exists in /boot
Check kernel line. Should be kernel /vmlinuz-<kernel-version> root=UUID=<root_uuid> vga=791, because /boot has it’s own partition. If it is just a directory under /, it should read kernel /boot/vmlinuz-<kernel-version> root=UUID=<root_uuid> vga=791.

17 : Cannot mount selected partition ¶

Play with root (hd<disk-number>,<partition-number>. GRUB will show you 21 : Selected disk does not exist or 22 : No such partition when you try a disk/partition that does not exist.

Ramdisk Image ¶

thanks, skrewz [3]:

kernel_version=2.6.28-11-generic
cd /tmp && rm -Rf w; mkdir w && cd w && cp /tmp/target/boot/initrd.img-$kernel_version i.cpio.gz && gunzip i.cpio.gz && cpio --extract --file=i.cpio && rm i.cpio
ls