More PXE Magic

In this article, I've decided to follow up on a topic I wrote about not in my column directly, but as a feature article called "PXE Magic" in the April 2008 issue. In that article, I talk about how to set up a PXE server from scratch, including how to install and configure DHCP and TFTP. Ultimately, I even provide a basic pxelinux configuration to get you started. Since then, PXE menus with pxelinux have become more sophisticated and graphical and could seem a bit intimidating if you are new to it. In this column, I explain how to piggyback off of the work the Debian and Ubuntu projects have done with their PXE configuration to make your own fancy PXE menu without much additional work. I know not everyone uses Debian or Ubuntu, so if you use a different distribution, hold off on the angry e-mail messages; you still can use the PXE configuration I'm showing here for your distro, provided it gives some basic examples of how to PXE boot its installer. Just use these steps as a launching off point and tweak the PXE config to work for you.

Simple Ubuntu PXE Menu

If this is your first time configuring a PXE server, for the first step, I recommend following my steps in the "PXE Magic" article to install and configure DHCP and TFTP. Otherwise, if you have existing servers in place, just make sure that DHCP is configured to point to your TFTP server (if it's on the same machine, that's fine). And, if you already have any sort of pxelinux configuration in your tftpboot directory, I recommend that you back it up and move it out of the way—I'm going to assume that your entire /var/lib/tftpboot (or /tftpboot on some systems) directory is empty to start with. For the rest of this article, I reference /var/lib/tftpboot as the location to store your PXE configuration files, so if you use /tftpboot, adjust the commands accordingly.
Both Debian and Ubuntu provide a nice all-in-one netboot configuration for each of their releases that makes it simple to PXE boot a particular release yourself. The file is called netboot.tar.gz and is located in a netboot directory along with the rest of the different install images. For instance, the netboot.tar.gz for the i386 Ubuntu 12.04 release (named Precise) can be found at http://us.archive.ubuntu.com/ubuntu/dists/precise/main/installer-i386/current/images/netboot/netboot.tar.gz.
To get started, cd to your tftpboot directory, and then use wget to pull down the netboot.tar.gz file (I'm assuming you'll need root permissions for all of these steps, so I'm putting sudo in front of all of my commands), and then extract the tarball:

$ cd /var/lib/tftpboot
$ sudo wget http://us.archive.ubuntu.com/ubuntu/dists/precise/
↪main/installer-i386/current/images/netboot/netboot.tar.gz
$ sudo tar xzf netboot.tar.gz
$ ls
netboot.tar.gz  pxelinux.0  pxelinux.cfg  
 ↪ubuntu-installer  version.info

As the ls command shows, an ubuntu-installer directory was created along with pxelinux.0 and pxelinux.cfg symlinks that point inside that ubuntu-installer directory to the real files. Without performing any additional configuration, provided your DHCP and TFTP servers were functioning, you could PXE boot a server with this configuration and get a boot menu like the one shown in Figure 1.


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