How to create a customized distribution based on Debian?

Question

I need to create a network with a small group of users. I thought about using Debian distro within computers. To automate it, I searched for automatic installation and customization tools for Linux distros. I could not find any exact matches that are suitable for my needs.

How can I create an ISO image that has the programs I need?

Solution

What you want is called a preseed installation. A preseed install is one in which the debconf database is pre populated (or "preseeded") with all of the answers you will be asked during the installation process.

You can find instructions here:

• http://users.telenet.be/mydotcom/howto/boot/boot_linux.htm (etch specific)
• http://www.debian.org/releases/stable/i386/apb.html.en (for the current stable release)
• http://www.debian.org/releases/stable/amd64/apb.html.en (for the current stable amd64 release)

The first link is etch specific, but it's not terribly different from creating a Squeeze image.

In a nutshell:

1. Copy the contents of the net install ISO to a working directory
2. Edit isolinux.cfg to use only a single install target and set:
   1. default install
   2. The Kernel append line to include the preseed file, the locale and the keymap (e.g., append vga=normal initrd=/install.amd/initrd.gz preseed/file=/cdrom/preseed.txt debian-installer/ locale=en_US console-keymaps-at/keymap=us --)
3. Run debconf-get-selections on a system that was installed normally, save the output to preseed.txt and place it at the root of your ISO working directory
4. Build the image (using mkisofs) and try it
5. Edit preseed.txt as necessary and repeat step 4 until you have a fully unattended installer.

It helps if you use VirtualBox (or similar) for rapid iteration.

Comments

[Admin]

I'm not that familiar with Debian, but I know for a fact that they have an automated installation system. For Fedora/Red Hat there is the kickstart functionality.

[Jeff Hewitt]

The kernel command line need not actually include anything but the url/path to the preseed file. To ensure that you skip "unimportant" questions (assuming default answers), you can append auto=true priority=critical to your kernel command line. @buraker I've recently managed something similar. If you hit any snags, my e-mail is in my profile, I'd be happy to help :)

[Jeff Hewitt]

I second the suggestion to use VirtualBox. It's indispensable in this case.