Remastring Tutorial

1.     Start with VirtualBox. It’s a virtual machine tool for MacOS (and others). I’ve not worked much with virtual machines but this absolutely rocks. You just create a virtual machine, tell it how much RAM, HDD, etc you want. You can manipulate all the IO devices easily. Just download an .iso file or link the CDROM drive to the real drive in your computer and off you go.You can also make snapshots of the entire state machine and thus installation and configuration are way easier, if you’re ever unsure. And believe me I made a lot of mistakes along the way.So create a virtual box. Give it +500MB  RAM and 5GB HDD.

2.     Download mini.iso from Ubuntu. Link this file to your virtual CDROM drive and start the machine. Ubuntu will boot a minimal LiveCD system and allow you to install a Ubuntu system on your virtual Drive. Instead of selecting individual packages I chose the “Xubuntu” preconfig.

3.     Remove the virtual CD and reboot. Using Firefox download Chrome 16 (or later). You should download the .deb package since Ubuntu is derived from Debian. Set the user to “username” and give it a password. You’ll need this in the following setup process.

4.     Open a terminal. Navigate to where the .deb file got downloaded to and do:

 sudo dpkg –i google-chrome*.deb

This will likely throw some unsatisfied dependencies.
Resolve them by using

sudo apt-get install [package name ]

Then re-issue the dpkg command :

sudo dpkg –i google-chrome*.deb

Start chrome with

/opt/google/chrome/chrome

Set up chrome the way you like. In my case I had to install a plugin and configure it.

5.     Next install remastersys.
First you need to get a security key from remastersys and then register their site in /etc/apt/sources.list so that apt-get will know where to get it from. Simply do:
wget http://www.remastersys.com/ubuntu/remastersys.gpg.keysudo apt-key add remastersys.gpg.key Then, add the following line that corresponds to your version of Ubuntu to your /etc/apt/sources.list

#Remastersys Lucid

deb http://www.remastersys.com/ubuntu lucid main

#Remastersys Maverick

deb http://www.remastersys.com/ubuntu maverick main

#Remastersys Natty

deb http://www.remastersys.com/ubuntu natty main

#Remastersys Oneiric

deb http://www.remastersys.com/ubuntu oneiric main

In my case it was the last one.

Now you just need to do:

sudo apt-get update

sudo apt-get install remastersys

6.     Do a ‘df’, and you’ll see your system is currently about 2.2GB (at least it was in my case).  This, compressed, will make an .iso file that is about 750MB, which unfortunately doesn’t fit on a CD. So to get the final LiveCD ISO to be as small as possible we want to loose all the weight we don’t need. This was slightly tricky and required a few attempts to get right. It was important to preserve all Chrome functionality, auto Xstart capability and all sound playing ability. I definitely screwed up each of these at least once.

So therefore the next step is to

Make a snapshot of the Virtual Machine using VirtualBox

7.     Now, go and do

sudo apt-get install aptitude

sudo aptitude

I went in an removed a lot of stuff, all window managers, firefox, editors, graphics programs, documentation, etc etc. All sorts of crap you don’t need.

You need to make sure to not remove anything that what you need is dependent on though! I did this largely by trial and error. I’d choose enough packages to loose about 200MB (Aptitude will tell you in the upper right hand corner how much its removing) and let you know about dependenceies. I’d then hit ‘g’ remove the packages, quit aptitude, reboot the machine (sudo reboot) and see if chrome and X and sound still worked. If so I’d make another snapshot on VirtualBox and continue, if not I’d go back to the last snapshot and try again.

Apparently I needed to preserve certain parts of Gnome and importantly GDM. Also ALSA sound drivers need to stay obviously. There’s a lot of stuff that seems like it’s not needed but essential parts are dependent on it. Anyway, I managed to reduce the system size to about 1.35 GB, which awesomely reduces down to an .iso of about 450MB!

8.     Ok, so I wanted the system to just boot straight into Chrome running in X, alone, with not window managers, nothing.

So you need to add these lines to /etc/gdm/custom.conf:

AutomaticLoginEnable=true

AutomaticLogin=[username]

(replacing [username] with your username of course. And to get chrome to start up create a script ~/start_chrome.sh:

#!/bin/sh

/opt/google/chrome/chrome http://www.mystartsite.com

and make it executable:

chmod 755 ~/start_chrome.sh

then edit ~/.xsession (or create it if it’s not already there) and add

#!/bin/sh

/home/[username]/start_chrome.sh

Just in case make that file executable too

chmod 755 ~/.xsession

9.     Ok, you’re set. Reboot. Hopefully you’ll end up in X without any login prompts in chrome loading your favourite page. Now you wont have any menus or whatever – so to break out into a shell press Ctrl+Alt+F1  (add fn if on a Mac). (This always works on X btw). Ok, now back in the shell. Be sure to remove any temporary files which are no longer needed, as space on a CD is limited. A classic example is downloaded package files, which can be cleaned out using:

sudo aptitude clean

sudo rm -rf /tmp/* ~/.bash_history

sudo rm /etc/hosts

sudo rm /var/lib/dbus/machine-id

10.  Ok, so assuming you’re happy with your setup, to create the actual .iso image, you just have to do:

sudo remastersys backup livecd.iso

It should place the file livecd.iso in /home/remastersys/remastersys/

11.  You could try and burn that .iso to a real CDROM by linking up your real drive to the virtual machine with VirtualBox.

cdrecord dev=/dev/cdrom livecd.iso

I didn’t try that. Instead, to get that file out of the virtual machine I just used scp and uploaded it to antoher ssh server of mine and then downloaded it back to my Mac and just used DiskUtil to burn the CD. Now that is clearly stupid. A better way might be to mount another, real, drive inside the virtual machine or a USB stick. Again I didn’t try this but it seems very reasonable. Even better would be to have a way to mount the VirtualMachine’s drive (it’s a .vdi file) somehow on the Mac but I wasn’t able to find a way to actually do that. Seems like it should be no brainer. Anyway. You can also test you .iso by creating another virtual machine on VirtualBox and shoving the new .iso in the virtual CD drive. I recommend doing that before burning a physical CD since it will save you time if something messed up. Anyway, all this was a lot of fun and a very neat way to deal with readymade systems.

Another cool thing would be to burn the iso to a thumbdrive. I had some success in making bootable thumbdrives using a windows machine. I tried doing the same on a Mac and it just would not boot anywhere even though the filesystems etc were set up ok on the drive. Having the bootable system on the drive is superior in the sense that any post-boot changes you make (like cookies etc). will be remembered on the next boot, while they’re totally lost on the CD.