C.4. Installing Debian GNU/Linux from a Unix/Linux System

This section explains how to install Debian GNU/Linux from an existing Unix or Linux system, without using the menu-driven installer as explained in the rest of the manual. This “cross-install” HOWTO has been adapted from the Debian Installer guide for debonaras.org .This guide is for NSLU2 with OpenSlug, you can't run it on UcSlugC. In this section some familiarity with entering *nix commands and navigating the file system is assumed.

Once you've got the new Debian system configured to your preference, you can migrate your existing user data (if any) to it, and keep on rolling. This is therefore a “zero downtime” Debian GNU/Linux install. It's also a clever way for dealing with hardware that otherwise doesn't play friendly with various boot or installation media.

C.4.1. Getting Started

With your current *nix partitioning tools, repartition the hard drive as needed, creating at least one filesystem plus swap. You need at least 128mb for the base debootstrap. That includes 42mb of packages you can clean out when you get into the chroot. More space is prefered if you want to install any software at all.

To create file systems on your partitions. For example, to create an ext3 file system on partition /dev/sda1 (that's our example root partition):

# mke2fs -j /dev/sda1

To create an ext2 file system instead, omit -j.

Initialize and activate swap (substitute the partition number for your intended Debian swap partition):

# mkswap /dev/sda2
# sync; sync; sync
# swapon /dev/sda2

Mount one partition as /mnt/debinst (the installation point, to be the root (/) filesystem on your new system). The mount point name is strictly arbitrary, it is referenced later below.

# mkdir /mnt/debinst
# mount /dev/sda1 /mnt/debinst

Note

If you want to have parts of the filesystem (e.g. /usr) mounted on separate partitions, you will need to create and mount these directories manually before proceding with the next stage.

C.4.2. Install debootstrap

The tool that the Debian installer uses, which is recognized as the official way to install a Debian base system, is debootstrap. It uses wget and ar, but otherwise depends only on /bin/sh. Install wget and ar if they aren't already on your current system, then download and install debootstrap.

Or, you can use the following procedure to install it manually. Make a work folder for extracting the .deb into:

# cd /mnt/debinst
# mkdir work
# cd work

The debootstrap binary is located in the Debonaras archive.. Download the debootstrap .deb from the pool, copy the package to the work folder, and extract the binary files from it. You will need to have root privileges to install the binaries.

# ar -x debootstrap_0.X.X_arch.deb
# zcat data.tar.gz | tar xv

Please edit the usr/sbin/debootstrap script and change DEBOOTSTRAP_DIR= to point at the location of your debootstrap file.

# vi ./usr/sbin/debootstrap

( /mnt/debinst/work/usr/lib/debootstrap )

Note that running debootstrap may require you to have a minimal version of glibc installed (currently GLIBC_2.3). debootstrap itself is a shell script, but it calls various utilities that require glibc. (i.e. you can't run it on UcSlugC)

C.4.3. Run debootstrap

Substitute one of the following for ARCH in the debootstrap command: alpha, arm, armeb, hppa, i386, ia64, m68k, mips, mipsel, powerpc, s390, or sparc.

# ./usr/sbin/debootstrap --arch ARCH sarge /mnt/debinst http://ftp.debonaras.org/sarge/debian

( For nslu2 that is armeb )

C.4.4. Configure The Base System

Copy over working interfaces file, later we will add more to it.

#  cp /etc/network/interfaces /mnt/debinst/etc/network/interfaces

Now you've got a real Debian system, though rather lean, on disk. Chroot into it:

# LANG= chroot /mnt/debinst /bin/bash

C.4.4.1. Mount Partitions

You need to create /etc/fstab.

# editor /etc/fstab

Here is a sample you can modify to suit:

#################START#####################################
# /etc/fstab: static file system information.
#
# file system    mount point   type    options                 
/dev/sda1       /               ext3    defaults        1  1
/dev/sda2       swap            swap    defaults        0  0
proc            /proc           proc    defaults        0  0
usbfs           /proc/bus/usb   usbfs   defaults        0  0
####################END#####################################

Use mount -a to mount all the file systems you have specified in your /etc/fstab, or to mount file systems individually use:

# mount /path   # e.g.: mount /usr

You can mount the proc file system multiple times and to arbitrary locations, though /proc is customary. If you didn't use mount -a, be sure to mount proc before continuing:

# mount -t proc proc /proc

The command ls /proc should now show a non-empty directory. Should this fail, you may be able to mount proc from outside the chroot:

# mount -t proc proc /mnt/debinst/proc

C.4.4.2. Configure Keyboard

To configure your keyboard:

# dpkg-reconfigure console-data

Note that the keyboard cannot be set while in the chroot, but will be configured for the next reboot.

C.4.4.3. Configure Networking

To configure networking, edit /etc/network/interfaces, /etc/resolv.conf, and /etc/hostname.

# editor /etc/network/interfaces

Here are some simple examples merged from nslu2 and debonaras wiki , plus some irc logs:

##########################START########################################
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# See the interfaces(5) manpage for information on what options are
# available.
######################################################################
# We always want the loopback interface.
#
auto lo
iface lo inet loopback
#
# The NSLU2 built-in ethernet
auto eth0
# The pre-up option must always be supplied, regardless
# of configuration, to set the hardware correctly.
# Severe network problems may result if this option is
# removed.
iface eth0 inet dhcp
pre-up modprobe -f ixp425_eth
        pre-up modprobe -f ixp400
        pre-up ifconfig eth0 hw ether 00:04:5A:XX:YY:ZZ 
# make sure you copy in your own ethernet MAC address from the sticker on the bottom of your slug, replace XX:YY:ZZ

# set static fallback address ...
# It would be a good idea to set this, really.
#address give.me.an.ip
#netmask give.me.a.netmask
#gateway give.me.a.gw
#
#######################END##################################################

Edit your nameserver(s) and search directives in /etc/resolv.conf:

# editor /etc/resolv.conf

A simple /etc/resolv.conf:

##########START##################
search hqdom.local\000
nameserver 10.1.1.36
nameserver 192.168.9.100
##################END#############

Enter your system's host name (2 to 63 characters):

# echo DebianHostName > /etc/hostname

If you have multiple network cards, you should arrange the names of driver modules in the /etc/modules file into the desired order. Then during boot, each card will be associated with the interface name (eth0, eth1, etc.) that you expect.

C.4.4.4. Configure Timezone, Users, and APT

Set your timezone, add a normal user, and choose your apt sources by running

# /usr/sbin/base-config new

For now choose apt-sources by hand and edit your /etc/apt/sources.list , add this:

#########START#######################
# Use this /etc/apt/sources.list for now please
deb http://ftp.debonaras.org/sarge/debian sarge main
deb http://ftp.debonaras.org/sarge/debonaras sarge main
###########END######################## 

C.4.4.4.4. NSLU2 related.

Update you package lists:

# apt-get update
Update from modutils to module-init-tools:
# apt-get remove modutils  
# apt-get install module-init-tools  
# rm /etc/rcS.d/S20modutils
Update to udev:
# apt-get install udev

We want to be popular so please install the popcon package.

# apt-get install anacron popularity-contest

We need ssh to be able to connect to the slug after boot.

# apt-get install ssh
(Note that this will generate new ssh host keys, replacing the ones that OpenSlug's ssh was using, which will make your ssh client complain when you reconnect later.)

Edit /etc/inittab to disable the tty[1-6] entries and add the following serial console entry:

S0:2345:respawn:/sbin/getty 115200 ttyS0

Edit /etc/init.d/checkroot.sh to remove /.recovery rm -f /.recovery

C.4.4.5. Configure Locales

To configure your locale settings to use a language other than English, install the locales support package and configure it:

# apt-get install locales
# dpkg-reconfigure locales

NOTE: Apt must be configured before, ie. during the base-config phase. Before using locales with character sets other than ASCII or latin1, please consult the appropriate localization HOWTO.

C.4.5. Install a Kernel

If you intend to boot this system, you probably want a Linux kernel and a boot loader. Identify available pre-packaged kernels with

# apt-cache search kernel-image

Then install your choice using its package name. For now that is the nslu2 kernels in the debonaras feed.

# apt-get install kernel-image-2.X.X-arch-nslu2

Kernel does NOT include the IXP modules, as they are not DFSG-compliant!

So we either symlink the OpenSlug modules since you already have them installed on the flash and you have accepted the license by installing OpenSlug already (1). Or we copy the modules over from the openslug rootfs (2).

(1) # rm -rf /lib/modules ; ln -s /initrd/lib/modules /lib/modules
(2) Be outside the chroot # cp -R /lib/modules/2.6.12.2/* /mnt/debinst/lib/modules/2.6.12.2/

Please make sure kernel versions match.

We need to prepare for umounting the Debian rootfs.

# /etc/init.d/anacron stop
# /etc/init.d/exim4 stop
# /etc/init.d/syslogd stop
# umount /proc/bus/usb/
# umount /proc/
# swapoff -a

You may need to kill syslogd the hard way, with 'kill -9 syslogd.pid'

C.4.6. Set up the Boot Loader

To make your Debian GNU/Linux system bootable, we rely on the OpenSlug in flash to load the installed kernel with your new root partition. Note that debootstrap does not install a boot loader, we need to get out of the Debian chroot to set this up. OpenSlug is used both as a boot loader and as a recovery root filesystem.

Exit the Debian chroot for the next steps.

# exit

Reflash the new Debian kernel.

# reflash -k  /mnt/debinst/vmlinuz

Unmount the Debian rootfs

# cd /
# umount /mnt/debinst

Turnup disk get you new root fs to load

# turnup disk -s7 /dev/sda1 -t ext3
You should read turnup help if you have memorysticks or nfs as your / .