Today I dug up some old software, where I want to re-use a certain part, shamefully it uses a library that is 32bit. (But is the only library I know off that can do this things, this nicely (shamefully not free)).

But I did not want to setup a 32bit virtual machine and be forced to copy files from one point to the other and back all the time. So I setup a a chroot.

I will now quickly describe the steps I took. I post them here, because many manuals I found on the internet had errors in them (I probly will have to) or used old config formats.

Installing the required software

The software I am going to use is: *schroot. *I use debootstrap to install the 32bit linux environment.

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sudo apt-get install schroot debootstrap

Installing 32bit ubuntu using debootstrap

First create a directory to store the distro in, preferable outside your home directory. I used /Storage/chroot/

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mkdir -p /Storage/chroot/natty32/

Now debootstrap natty in here:

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sudo debootstrap --arch i386 natty /Storage/chroot/natty32/ http://ftp.tudelft.nl/archive.ubuntu.com/

This will take 2 minutes or so. (depending on internet and hard-disk speed).

Configuring SCHROOT

Now this is going to be the ‘hardest’ part. Edit /etc/schroot/schroot.conf and add the following section.

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[natty32]
description=Ubuntu natty
directory=/Storage/chroot/natty32/
users=qball
groups=users
root-groups=root
personality=linux32
script-config=desktop/config
type=directory

• users: your username.
• directory: location of your chroot
• type: the type of chroot, we use the ‘directory’ type. (see man page for all the possibilities).
• personality: linux32. This makes sure your target is 32bit. (so you do not need to type linux32 in front of everything).
• script-config: This does most of the voodoo, see man page and  */etc/schroot/desktop/** to see what it does.
• etc.

Switching to 32 bit

To switch to the 32bit environtment, just type the following command:

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schroot -c natty32

You see that your promt says (natty32)username@host:~$, this means your now in your 32bit environment. (type uname -a to verify).

But you are still in your own home-directory, with access to all your files!

Installing software, to make it usefull

Warning, the debootstrapped linux is very very basic, so you need to install a lot of extra tools (like vim, build-esssentials, sudo)

First we install sudo:

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sudo schroot -c natty32
 
(natty32)root@host:~qball$ apt-get update; apt-get install sudo vim
 
(natty32)root@host:~qball$ exit

With sudo installed you can just do (as normal user) sudo apt-get install  inside the 32bit environment.

You might also want to enable multiverse, universe and restricted repository in /Storage/chroot/natty32/etc/apt/sources.list.

deb http://ftp.tudelft.nl/archive.ubuntu.com natty main restricted universe multiverse
deb-src http://ftp.tudelft.nl/archive.ubuntu.com natty main restricted universe multiverse

 
And that is all there is to it. This way you can very easily switch between 64/32bit, if you want even different versions of ubuntu. (but you will still use the same kernel and drivers!!)