Ubuntu can work as a network boot server. For example, workstations can PXE boot to Ubuntu
installer and install Ubuntu trough network. I describe a working setup to create a PXE boot
server with Ubuntu 8.04, ISC DHCP-server and HPA TFTP-server.

DHCP server distributions network information: ip address, mask, default gateway and nameservers.

See Ubuntu DHCP.

In PXE network booting, DHCP server tells client where to download bootloader image.

Add to the global scope of your dhcp.conf:

next-server 172.28.1.221; # TFTP server ip address
filename "pxelinux.0"; # name of bootloader image

In PXE network boot, the files needed for booting are served with TFTP. Trivial FTP (TFTP) should not be confused with FTP, even if their names sound a bit similar.

The bootloader files served are:

• pxelinux.0 – bootloader, loaded first. (similar to GRUB but made for network boot)
• pxelinux.cfg/default – bootloader configuration, plain text (similar to GRUB /boot/grub/menu.lst)

Other files are referenced in pxelinux.cfg are kernel and initial ramdisk image:

• ubuntu-8.04/linux – kernel, core of the operating system, talks with hardware
• ubuntu-8.04/initrd.gz – initial ramdisk image contains shell and some programs

Install TFTP server

$ sudo apt-get install tftpd-hpa

Enable it. it’s beyond me why it’s not enabled by default:

$ sudo nano /etc/default/tftpd-hpa

Set RUN_DAEMON to yes.

RUN_DAEMON="yes"

Start TFTP server. Verify that it prints “Starting…”

$ sudo /etc/init.d/tftpd-hpa start
Starting HPA's tftpd: in.tftpd.

TFTP servers files from /var/lib/tftpboot.

Bootloader:

$ sudo apt-get install syslinux  # contains pxelinux.0 bootloader
$ sudo cp /usr/lib/syslinux/pxelinux.0 /var/lib/tftpboot/

Bootloader configuration:

$ sudo mkdir /var/lib/tftpboot/pxelinux.cfg
$ sudo nano /var/lib/tftpboot/pxelinux.cfg/default

# pxelinux.cfg/default - network boot loader configuration
# (c) 2008 Tero Karvinen www.iki.fi/karvinen
# All paths are relative to pxelinux.0 path, usually /var/lib/tftpboot
display welcome.txt
prompt 1
timeout 30      # seconds
default ubuntu-8.04
label ubuntu-8.04
      kernel ubuntu-8.04/linux
      # append must be on a single line
      append initrd=ubuntu-8.04/initrd.gz ramdisk_size=64000 root=/dev/rd/0 rw -- debian-installer/locale=en_DK kbd-chooser/method=fi netcfg/get_hostname=x netcfg/get_domain=x

Kernel and initial ramdisk image (these examples are for amd64 cpu architechture):

$ wget http://fi.archive.ubuntu.com/ubuntu/dists/hardy/main/installer-amd64/current/images/netboot/ubuntu-installer/amd64/linux
$ wget http://fi.archive.ubuntu.com/ubuntu/dists/hardy/main/installer-amd64/current/images/netboot/ubuntu-installer/amd64/initrd.gz

$ sudo mkdir /var/lib/tftpboot/ubuntu-8.04
$ sudo mv linux initrd.gz /var/lib/tftpboot/ubuntu-8.04/

It’s much easier to catch TFTP problems now than later.

$ mkdir testdir
$ cd testdir
$ tftp -v localhost -c get pxelinux.0
Connected to localhost (127.0.0.1), port 69
getting from localhost:pxelinux.0 to pxelinux.0 [netascii]
Received 14296 bytes in 0.2 seconds [702075 bit/s]
$ ls -l  # verify that file size is greater than zero
-rw-r--r-- 1 tee tee 14146 2008-09-11 12:58 pxelinux.0

$ sudo apt-get install syslinux