Cook up tasty custom Ubuntu live CDs with UCK

Live CDs let you boot an operating system without installing any software on a hard drive. There are plenty of Linux live CDs and lots of tools to customize them. The Ubuntu Customization Kit, tastefully called UCK, lets you add your favorite applications into the distro. If you’re not happy with the factory-installed Ubuntu apps, here’s your chance to spin up your very own Ubuntu live CD without too much effort.

Installing UCK is a no-brainer — grab the latest .deb package and use GDebi to install it. UCK requires tools such as fakeroot and mkisofs, which you can install using Synaptic. In addition to UCK, you need about 5GB of free disk space under your home directory, as well as the ISO of the Ubuntu version you want to customize. UCK supports four flavors of Ubuntu — the GNOME-based original Ubuntu, KDE-based Kubuntu, Xfce-based Xubuntu, and education-targeted Edubuntu. You must also be running the same Ubuntu version that you want to customize.

Once installed, UCK can be accessed from under Application -> System Tools -> Ubuntu Customization Kit or from the command line using the uck-gui command. The tool was originally written to create localized versions of the Ubuntu live CD, and it can still do so, but it can also be used to add and remove applications; copy, paste, and tweak files; and change the configuration of the customized live CD.

UCK’s graphical interface takes you through various steps involved in customizing a live CD. The first two steps involve selecting the language packs and the bootloader language. You can select as many language packs as you want, but you can select only one bootloader language. Make sure the bootloader of the Ubuntu version you are customizing supports this language, else the live CD will fail to compile. The third step is selecting the desktop environment (KDE, GNOME, Others) whose localized strings you want to download.

Before it goes to work, UCK asks you to point it to the ISO of the Ubuntu version you want to customize, and gives you a text box to type in a name for the new live CD. It also asks if you wish to customize the CD manually. This is important if you wish to add other packages or transfer files to the live CD. By default, an Ubuntu live CD contains a lot of files that help it run and display usage information if it’s inserted in a Windows machine. The UCK interface allows you to remove all the Windows-related information from the live CD, which frees up some space.

When it has all this information, UCK mounts and unpacks the Ubuntu ISO and the SquashFS image under the ~/tmp/ directory. Depending on our computer’s specs, this can take a long time. Once everything has been unpacked, UCK copies some customization scripts and the local apt-cache to the ~/tmp/ directory before downloading the language packs you selected and removing all the others.

When it’s done with the language packs, UCK displays a menu to let you customize the live CD. The first option launches Synaptic, which you can use to add and remove packages and their dependencies. The second option launches a terminal and places you in a chrooted environment of the live CD you are customizing. You can use apt-get here to install packages if you prefer using the command line. If you want to tweak the configuration settings for the desktop and applications, you can do so by launching gconf-editor from within the chrooted environment.

You can also copy files into the live CD you are customizing. To do this, launch another terminal and cd to ~/tmp/remaster-root/, which is the root of the customized live CD. It has the same directory structure as the distro installed on your machine. You can copy files into their appropriate folders under the remaster-root and UCK will include them in the live CD. For example, wallpapers in GNOME are under /usr/share/backgrounds. To copy a wallpaper into your new CD, copy it to ~/tmp/remaster-root/usr/share/backgrounds/.

UCK then packs the SquashFS image and creates an ISO file which it places under ~/tmp/remaster-new-files. Before you burn the ISO image to a CD, I suggest you test it out using one of the free virtualization applications, such as QEMU, Virtual Box, or VMware Server.

UCK is a newbie-proof tool to spin up a customized Ubuntu live CD in no time. If you’ve ever wanted to cook up that ultimate free software gaming live CD or a localized distro for your LUG, UCK is what you need.