Tutorial: Build Your Own Linux Distro

We're used to thinking of Linux distributions being set in stone. They're either KDE or Gnome, use a certain kernel and bundle certain applications. But this doesn't have to be the case. If you find yourself making the same adjustments each time you install a new distribution, it's worth creating your own customised version. Revisor is a tool that lets you do just this, and in this tutorial, we'll show you how...

Update: And don't feel left out if you're a Windows user. Check out our tutorial about how to build your own Windows. And if you're a die hard Linux fan, check out our guides to cluster computing in Linux and booting into Linux over a network, Finally, if you want an even flashier way to put together a distro, why not use SUSE's tools and build it online?

1. Install Fedora

The Revisor tool has been a part of the Fedora distribution for the last few releases. This means you can use any of these versions to create your own Linux distribution, although we'd recommend using the latest – Fedora 10. Installation is very straightforward, and shouldn't be a problem if you've installed any other version of Linux from the last two years.

After installing the operating system, the only other prerequisite is the Revisor application itself. This can be installed by clicking on the Administration menu, selecting 'Add/Remove software' and searching for a package called revisor. Click ‘Apply’ and accept the additional packages that need to be installed.

However, there is one step that is vital to success, and that's updating Fedora to include the very latest patches. You can do this using the Update tool in the Administration menu. This is required because the version of Revisor that was bundled with Fedora 10 was broken, and this won't create a workable Live CD. You need to either use an older version, or update your 10 installation to use the fixed version of Revisor.

2. Disable security

After installation, Revisor can be found in the Applications | System Tools menu. Click on the icon and enter your root password. If you see an SELinux error, you will need to change a security setting for your system. SELinux is an ultra-tight Linux security system that keeps a close eye on what certain application can and can't do. Revisor falls out of its remit, so you need to change its level of protection to Permissive.

To do this, load the SELinux Management application from the System | Administration menu and change the Current Enforcing mode to Permissive. When you launch Revisor again, the error will have disappeared.

3. Getting started

From the Revisor main window, click 'Get Started'. You now have to decide how your new distribution will be booted. You can choose between the standard installation and Live media. The first option is a good choice if you're planning to install your own version of Fedora on many different machines, for example, in an office. The DVD or CD you create will let you install your own distribution, complete with your own set of applications, without any prompting. If you want to create your own distribution for personal use, then the chances are you'll find the Live media types more useful.

This creates either a Live CD/DVD or a USB stick installation of your distribution, and you'll be able to boot into your desktop from either of these installations by simply inserting the media into your PC. As with any Live media, you'll be able to work on your desktop and use the applications you choose, but your distribution won't touch the host machine's hard drive. This is a great solution for Internet cafes or college PCs. We've opted for the Optical media type installation, as we find this is the most flexible.

4. Repository information

Click on the ‘Forward’ button to bring up the package repository configuration page. This lists the sources for the packages that are going to be installable for your distribution, as well as the packages for a specific hardware type. These are decided by the option to the right of Configuration Section to Use, and by default this is set to the most generic option – f10-i386. If you want to build your Linux distribution for a different platform, such as Intel 64-bit or PowerPC, then you will need to use a version of Fedora running on that hardware. You can't build a distribution for an architecture different from the one which Revisor is running on.

Other than system architecture, another option you might want to change is the Destination Directory. This is where the final image for your distribution will be built. Beneath this option, you will see a list of the repositories that are going to be used for pulling the packages you want to include in your distribution. We disabled all but the simple Fedora repository.

5. Package management

Skip the page titled Load Kickstart Data. The step after this is the most important because it's where you get to choose the packages that are going to be installed on your own distribution. Not only will this selection define what can and can't be done with your distribution without any further modification, it will also define exactly how big your distribution is going to be. That's important if you want to fit everything onto CD.

If you do need to keep package size to a minimum, then we'd recommend opting for the XFCE desktop environment, rather than the fatter Gnome or KDE options. These are ideal choices if you want a more powerful environment, but you'll need a DVD's worth of capacity to make the distribution useful. You should also install everything listed in the base category, as these packages are needed to create a functional environment. By default, the Package Selection screen only displays groups of packages, rather than individual selections. If you want to install GIMP, for example, you need to switch to the Search view and type 'gimp' into the find field. You can then select the package from the results list. You should consider installing a web browser (Firefox), a word processor (OpenOffice.org), a music player (Amarok or Rhythmbox) and a video player (totem).

6. Distro configuration

You now have the opportunity to fine-tune your distribution to your liking. The first page is the most important, as this lets you define your language and keyboard layout, as well as the root password for your Live system. You can ignore the kernel parameters and the authentication page, although you should also add a single default network device on the following page and leave the firewall enabled for safety. You may also want to create a default user account.

When you're happy with your customisations, click on the ‘Forward’ button. Revisor will calculate dependencies (those packages that are required to make your selection work), and tell you how much space your distribution is going to use. If this is too much for your install medium, you will need to click 'Back' and remove some of the packages you've selected.

7. Composition

A basic installation of XFCE and GIMP took up around 700MB in our example. Clicking 'Forward' one more time will start the compilation process. This consists of 11 separate steps.

1. Packages are downloaded
2. The file system is created
3. Packages are installed
4. The system is configured
5. Networking is configured
6. The RAM file system is created
7. The system is relabelled
8. The bootloader menu is installed
9. File systems are unmounted
10. The kernel image is compressed
11. The ISO image is created

The speed with which all of this is accomplished is obviously dependent on the number of packages you've chosen, the speed of your Internet connection and the capabilities of your machine. But to give you a ballpark figure, our Intel Core 2 Duo 6400@2.13GHz machine took around 90 minutes to build a 700MB-sized distribution.

8. Burn the disc

After the generation of the file has completed, you will find the final ISO located in a '/srv/revisor' subdirectory (as long as you didn't change that earlier). Our file was hidden in the Live folder, and called Fedora-10-Live-i386.iso. You need to burn this file to a blank CD, and you can do this from within Fedora by right-clicking on the ISO file and selecting 'Write to disc'. You have to be careful with ISO images, as you don't want to mistakenly write them as a single file to a new disc. You need to make sure they're used as an image to copy the contents from the ISO file onto the disc.

9. Give it a spin

When the burning process has finished, you're ready to launch your freshly squeezed Linux distribution. Insert the disc into the optical drive of your machine and reboot. You will also need to make sure that your system is configured to boot from the optical drive, either through your system BIOS or by a boot-time device selection menu.

This article originally appeared in Issue 279 of PC Plus.

Graham Morrison