Installing Debian using network booting

Preface

Installation using network booting must not be confused with DebianNetworkInstall. In network install, you start with a CD to install a minimal Linux system before you proceed to download further packages over the network. Here, in network booting, you need no CD at all. You instruct your BIOS boot menu to boot directly from the network.

To do so, you need a network boot server. As there are no fiducial boot servers out in the wild, you need to setup your own. This is considerably more complicated than installing Debian from CD. Normally, network booting is only used if there is really no way to boot from CD.

In the Web, several articles can be found that describe in more or less detail how to setup a network boot server. They all have the same weakness: You are required to execute a long list of instructions without getting any feedback before the very end of the procedure when you try to boot. If it works, fine. If not, debugging will become very very difficult. Therefore in the following we break down the procedure into steps that can be debugged separately.

Preconditions

The computer you want to install to will be called the Client.

The computer you install from will be called the Server. We assume that the Server is running Debian.

To be specific, we assume that the Client and the Server are part of a LAN with the following IP addresses:

You will find out the value of x later.

The following instructions have been tested with Debian 6.0 (squeeze) in January 2012.

Change boot menu

Setup the BIOS boot menu of the Client to boot from the network.

Reboot. This should produce an output that contains the Client's MAC address. Then, it will fail with

  PXE-E53: no boot filename received.

Note the MAC address, you will need it in a minute.

Set up DHCP server

On the Server, we need to set up a DHCP server.

Current best practice seems to be to use the package isc-dhcp-server, which provides a daemon dhcpd.

It's configuration file is /etc/dhcp/dhcpd.conf. Modify this file so that it contains about the following; adapt IP and MAC addresses to your local needs:

default-lease-time 600;
max-lease-time 7200;

allow booting;
allow bootp;

# in this example, we serve DHCP requests from 192.168.0.(3 to 253)
# and we have a router at 192.168.0.1
subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.3 192.168.0.253;
  option broadcast-address 192.168.0.255;
  option routers 192.168.0.1;             # our router
  option domain-name-servers 192.168.0.1; # our router, again
}

group {
  next-server 192.168.0.2;                # our Server
  host tftpclient {
    hardware ethernet  00:12:34:56:AB:CD; # replace by the MAC of your Client
    filename "pxelinux.0"; # (this we will provide later)
  }
}

After each modification of the above, restart the DHCP server with

  /etc/init.d/isc-dhcp-server restart

Check that it is actually running:

  ps axu | grep dhcp

Reboot the Client. On success, it will output the IP addresses of the Server ("DHCP"), of the router ("Gateway") and of itself (192.168.0.x). Then it will hang with a TFTP request, and finally write the error message:

  PXE-E32: TFTP open timeout

Setup a TFTP server

Next, we need to set up a TFTP server on the Server.

Again, there are several packages that provide TFTP (trivial FTP, unsafe, to be used in LAN's only). It seems best practice is using the package tftpd-hpa. On installation, a few question are asked. The response to these questions goes into a configuration file, /etc/default/tftpd-hpa. There should be no need to modify the following default contents:

  TFTP_USERNAME="tftp"
  TFTP_DIRECTORY="/srv/tftp"
  TFTP_ADDRESS="0.0.0.0:69"
  TFTP_OPTIONS="--secure"

Ignore older Web sites that instruct you to insert something like 'RUN_DAEMON="yes"'.

After each modification of the above configuration file, restart the TFTP server with

  /etc/init.d/tftpd-hda restart

Initially, this will fail with a message like

  Restarting HPA's tftpd: in.tftpd/srv/tftp missing, aborting.

Therefore, as root, create the directory /srv/tftp. Restart the TFTP daemon. Check that it is actually running:

  ps axu | grep tftp

Reboot the Client. You should error messages starting with

  PXE-T01: File not found

which is quite correct since we did not yet provide any files.

Provide the boot image

Download netboot/netboot.tar.gz from a Debian mirror, and unpack it to /srv/tftp, which should now contain

  debian-installer/
  pxelinux.0@
  pxelinux.cfg@
  version.info

It may be necessary to chmod -R a+w * to make all files in this directory readable for the TFTP daemon.

Restart the TFTP daemon, then reboot the Client. You should get to a Debian install screen.

Appendix

Other ressources