Setting Up a PXE Server on an RPM-based OS

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 AN!Wiki :: How To :: Setting Up a PXE Server on an RPM-based OS

This tutorial covers the steps needed to make a PXE server. It will be used for hosting multiple Operating Systems that can be booted from a machine's network card. The main reason for this setup is to host installation media removing the requirement for have optical drives in machines. It also saves you from having a pile of optical discs kicking around.

Prerequisite

This tutorial assumes that you have a fresh install of Fedora 13 and that the machine's eth0 device has been statically set to 192.168.1.10 and the subnet's router is set to 192.168.1.1. This should be easy to adapt to other distributions and network configurations.

Parts Needed

A PXE boot server is fairly strait forward. You need:

  • dhcp; This answers a workstation's request for an IP during the boot process.
  • tftp-server; This is a PXE compliant FTP server than handles passing the core boot files to the remote machine.
  • syslinux; This handles those special boot files that the remote machine needs to boot.
  • httpd; Once the boot files start up the remote machine, generally you will tell it to pull the main files from a webserver. This is the Apache webserver that will server that purpose.

dhcp

You're probably familiar with DHCP from a client perspective; It's the method used to get an IP address from most networks when you join them. This is a pretty old and simple protocol and is easy to setup.

A Word On Network Separation

Before you do though, you must take into account any other DHCP servers on your network. More to the point, you need to make sure there are no other DHCP servers on your network. The reason is that, when you try to PXE-boot a machine, it's up to the DHCP server that responds first to tell the client about the PXE server. If a "normal" DHCP server answers first, there simply won't be any instructions and your machine will not actually boot.

Configuration File

The core file to edit is /etc/dhcp/dhcpd.conf.

Note: On many systems, this *used* to be /etc/dhcpd.conf, but on Fedora 13 it's been moved into it's own directory. If you are adapting this tutorial for another operating system, please check to see where your server expects this file to be. 

vim /etc/dhcp/dhcpd.conf

### Global options
# General domain information
option domain-name "alteeve.com";
option domain-name-servers 192.139.81.117, 192.139.81.1;

# Tell the server that it's authoritive on our network.
authoritive;

### Subnet options
subnet 192.168.1.0 netmask 255.255.255.0 {
	# This is the DHCP server, but not the actual Internet gateway. So this
	# Argument points our clients to the right box.
	option routers 192.168.1.1;
	
	# Set our range. This can be whatever you want so long as it fits in
	# your netmask.
	range 192.168.1.100 192.168.1.220;
	
	# If clients don't ask, make the lease available for the following
	# number of seconds. If the client does ask, allow up to this number of
	# seconds. 86,400s = 24h.
	default-lease-time 86400;
	max-lease-time 86400;

	# These two options tell clients where to go to get the file needed to
	# start the boot process.
	next-server 192.168.1.10;
	filename "pxelinux.0";
}

Now set dhcpd to start with your machine and then start it up for the first time. 

chkconfig dhcpd on
/etc/init.d/dhcpd start

Done!

This isn't meant to be a dhcpd tutorial, so I am not showing a lot of options you may find useful. Please take the time to read the man dhcpd.conf and man dhcp-options page to see all the other neat things you can do.

tftp

This is the PXE-compliant FTP program that transfers the boot files from the PXE server to the client. It is pretty trivial to set up.

Edit /etc/xinted.d/tftp and simply add disable = no. The edited file should look like this: 

vim /etc/xinetd.d/tftp

# default: off
# description: The tftp server serves files using the trivial file transfer \
#       protocol.  The tftp protocol is often used to boot diskless \
#       workstations, download configuration files to network-aware printers, \
#       and to start the installation process for some operating systems.
service tftp
{
        disable                 = no
        socket_type             = dgram
        protocol                = udp
        wait                    = yes
        user                    = root
        server                  = /usr/sbin/in.tftpd
        server_args             = -s /var/lib/tftpboot
        disable                 = yes
        per_source              = 11
        cps                     = 100 2
        flags                   = IPv4
}

Being an xinetd service, that is what we need to enable at boot time and then start. 

chkconfig dhcpd xinetd
/etc/init.d/xinetd restart

Done!

pxelinux

In the xintd file for tftp was this line: 

        server_args             = -s /var/lib/tftpboot

This determines where the PXE boot files will be setup. Some people like to change this to be /tftpboot, but we'll keep it there to keep things simple. In Fedora, this directory already exists and should be world-readable. If it isn't for some reason, create it and set the permissions to 0755 or 0777, depending on your security requirements.

Credits

References used:

 

Any questions, feedback, advice, complaints or meanderings are welcome.
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