Sunday, 21 September 2008

Installing GNU/Debian Sid in Ubuntu Hardy using debootstrap and chroot

This article explains how to install GNU/Debian Sid in a previously installed Ubuntu Hardy System. We will use debootstrap and chroot tools to accomplish that. This how-to is not focused on security, it does not tell how to create a restricted chroot environment to improve security.

Ubuntu is a GNU/Debian based distro. Every six months they take GNU/Debian Unstable packages and make a new Ubuntu distribution.
Debian Sid provides more and newer packages. Ubuntu is configured for easiness. Debian has less preconfiguration instead.

chroot runs a command with a special root directory.
chroot comes as part of coreutils package.
$ sudo aptitude install coreutils

debootstrap command bootstraps a basic Debian system (it can also bootstrap other systems).
$ sudo aptitude install debootstrap

$ ls /usr/share/debootstrap/scripts/ #shows which distros and versions you can install with debootstrap:

breezy  edgy  etch-m68k  gutsy  hoary  lenny  sarge  sarge.fakechroot  warty  woody 
dapper  etch  feisty  hardy  hoary.buildd  potato  sarge.buildd  sid warty.buildd  woody.buildd


INSTALLATION BEGINNING

First of all we create the directory where Debian Sid will be installed.
$ mkdir DebianSid


CREATING A LOOPBACK IMAGE TO STORE DEBIAN SID

This step is only necessary if you plan to boot your system from your Debian Sid chroot environment.

$ sudo dd if=/dev/zero of=DebianSidFile bs=1048576 count=10000 #We create DebianSidFile with 10 gigabyte capacity.

$ sudo mkfs.ext3 -b 4096 -L DSid DebianSidFile #Ext3 filesystem creation.

$ sudo mount DebianSidFile DebianSid -t ext3 -o loop #mounting it on DebianSid directory.


INSTALLING A MINIMAL SYSTEM

$ sudo debootstrap --variant=minbase --verbose sid DebianSid http://ftp.debian.org/debian

it downloads, unpacks and installs a minimal Debian base system.


MOUNTING IMPORTANT FILESYSTEMS

$ sudo mount --bind /proc DebianSid/proc

$ sudo mount --bind /sys DebianSid/sys

$ sudo mount --bind /tmp DebianSid/tmp

$ sudo mount --bind /dev DebianSid/dev

$ sudo mount --bind /dev/pts DebianSid/dev/pts


NOTE: if you wanna share your user application configurations between Ubuntu and Debian you can mount home directory.

$ sudo mount --bind /home DebianSid/home



Copying the static lookup table for host names:

$ sudo cp /etc/hosts DebianSid/etc/


To resolve dns:

$ sudo cp /etc/resolv.conf DebianSid/etc/


ENTERING INTO THE CHROOT ENVIRONMENT

$ sudo chroot DebianSid

If we execute: #cat /etc/issue it will show:

Debian GNU/Linux lenny/sid \n \l

so we are in Debian Sid!!


NOTE: Setting the hostname also changes the original system hostname, better not to change it: e.g: #hostname DebianChrootSid


ADDING SEVERAL TOOLS TO OUR SYSTEM

Updating the package system database:
# apt-get update

Dialog interface to show messages:
# apt-get install dialog

To obtaing ping utility: #apt-get install inetutils-ping
We can test the network: #ping www.google.com

Installing less:
# apt-get install less

Small vi editor:
# apt-get install vim-tiny

apt-file: #apt-get install apt-file #to search for files and packages.
apt-file configuration: # apt-file update #This will take some time.

Installing man to read man pages: # apt-get install man-db


ADDING NEW USERS

# apt-get install adduser

adding user foo: # adduser foo

becoming that user: # su foo



INSTALLING AND CONFIGURING LOCALE SUPPORT

installing locales: # apt-get install locales


The easier way to configure locales is, using dialog interface, executing:
# dpkg-reconfigure locales


The hard way to configure locales is editing some configuration files:

we edit locale.gen file: # vi /etc/locale.gen

and uncomment the locale we want to generate:
e.g: #es_ES.UTF-8 UTF-8 for Spain

generate locales with: #locale-gen


After locales have been configured we can execute:

show available locales: # locale -a

selecting a locale: e.g: spanish locale: # export LANG="es_ES.UTF-8"

showing current locale: # locale



WAYS OF LAUNCHING OUR CHROOT ENVIRONMENT

STANDARD WAY

$sudo chroot DebianSid /bin/bash

This method maintains a lot of variables from the original environment, I dont like it.


LOGGING IN WAY

NOTE: To use this method you need to previously create a new user (with adduser) and assign a password to root (with passwd) because is not possible to log in as root user. You will have to login as a standard user and then execute su command to become root.


tty command tells which terminal is standard output attached to: eg: /dev/pts/3

$ sudo chroot DebianSid /sbin/getty 38400 `tty`

after you type sudo password you are offered a login prompt to enter in the chroot environment.



INSTALLING X-WINDOWS

Installing x-windows: #apt-get install xorg

Copying xorg configuration file from Ubuntu:

$ sudo mv /etc/X11/xorg.conf DebianSid/etc/X11/


window manager: # apt-get install ion2

starting X: # startx /usr/bin/ion2 -- :1


NOTE: if you cannot start the X server as a normal user change in /etc/X11/Xwrapper.config

allowed_users=console to allowed_users=anybody



SHOWING X APPLICATIONS IN THE UBUNTU DISPLAY

On ubuntu to allow connections from anyone:

$ xhost +


Better open only local connections: (in Ubuntu)

$ hostname #shows the hostname

$ xhost +local:`hostname`


now in the chroot environtment:

$ export DISPLAY=:0.0 # X display in Ubuntu.

$ xclock # an x window clock will show on the Ubuntu desktop screen.

this will work because we have shared X11 socket through /tmp dir with Ubuntu.



INSTALLING MPLAYER TO TEST VIDEO AND SOUND

After installing mplayer, video and sound should work fine:

Installing mplayer: # apt-get install mplayer



INSTALLING GNOME

Installing gnome: # apt-get install gnome

Starting gdm: # /etc/init.d/gdm start

NOTE: There is a problem with some gnome-applets because their configuration are shared with Ubuntu.



BOOTING FROM YOUR CHROOT ENVIRONMENT USING GRUB

At booting time you will be able to choose between booting from Ubuntu or from your chrooted Debian Sid.


You will have to add some lines to /boot/grub/menu.lst file to boot from your chroot environment.
Best idea is copying the lines at /boot/grub/menu.lst which ubuntu uses to boot Ubuntu and adapt them.

These are from my system. You will have to change 2.6.24-21 to your linux kernel version, loop=/usr/local/DebianSidFile to your DebianSidFile location, and your root device identifier.

title           kernel 2.6.24-21-generic DebianSid Loop
root            (hd0,0)
kernel          /boot/vmlinuz-2.6.24-21-generic root=UUID=a31628c8-5402-4319-b9cd-6a6183d43bc5 loop=/usr/local/DebianSidFile ro 
initrd          /boot/initrd.img-2.6.24-21-generic
quiet


NOTE: You have to use an ubuntu initrd.img file in order to understand the loop option.

Copy the necessary kernel modules into our chroot environment:
$ sudo cp -a /lib/modules/2.6.24-21-generic DebianSid/lib/modules


And reinstall grub: $ sudo grub-install /dev/sda #supposing master boot record is in /dev/sda device.

Now you can reboot your system into your chroot environment.


REFERENCE: http://ubuntuforums.org/showthread.php?t=24575

5 comentarios:

matla said...

hello,

My DebianSid directory is not a file but a part (/dev/sda6), mounted without loop option (/dev/sda6 on /mnt/system2 type ext3 (rw)).

Howto write the kernel line in menu.lst ?

kernel /boot/vmlinuz-2.6.24-24-generic root=UUID=... loop=/dev/sda6 ro

is it true ?

VicenteHA said...

Hi Matla,

since your Debian Sid directory is in a partition you have to change menu.lst this way:

title kernel 2.6.24-21-generic DebianSid

root (hd0,0)
You have to change (hd0,0) to the one it represents /dev/sda6, may be (hd0,5)

kernel /boot/vmlinuz-2.6.24-21-generic root=/dev/sda6 ro
initrd /boot/initrd.img-2.6.24-21-generic

Hope it helps,
Vicente.

matla said...

hi,

Thanks for your tutorial, i followed it with success and i have my debian sid chroot in a term.

But i try to start X desktop in chrooted debian Sid, and it doesn't work.

I have nvidia drivers in Ubuntu, and can't use the same drivers to start X desktop in the chroot.

UBUNTU
dpkg -l | egrep '(nvidia|2.6.24-24)'
ii linux-image-2.6.24-24-generic 2.6.24-24.56
ii linux-restricted-modules-2.6.24-24-generic 2.6.24.18-24.1
ii linux-ubuntu-modules-2.6.24-24-generic 2.6.24-24.39
ii nvidia-glx-new 169.12+2.6.24.18-24.1
ii nvidia-kernel-common 20051028+1ubuntu8


CHROOT DEBIAN SID
uname -a
Linux elisaktor 2.6.24-24-generic #1 SMP Tue Jul 7 19:46:39 UTC 2009 i686 GNU/Linux
dpkg -l | grep nvidia
ii nvidia-kernel-common 20080825+1

in debian sid sources (apt-cache), nvidia-kernel is version 2.6.26, and linux-image is version 2.6.30

when i start X , i have this xorg error message :

startx /usr/bin/icewm -- :1
...
(EE) Failed to load module "nvidia" (module does not exist, 0)
(EE) No devices detected.
...

in fact, i don't know if it's possible, but i need direct rendering in the debian sid chroot.

thank you if you know a way that can help me ..

matla

VicenteHA said...

Hi Matla,

not what you asked for, but a quick workaround:


your nvidia driver works fine in ubuntu, so you could start the Xorg server in Ubuntu. e.g:

startx /usr/bin/icewm -- :1

then in your chroot environment

export DISPLAY=:1.0
xterm

The xterminal should appear in :1 display if you shared /tmp dir between chroot and host and followed
"SHOWING X APPLICATIONS IN THE UBUNTU DISPLAY" instructions.

matla said...

it works now. thank you for your help !