PXE Network Installations using Linux Servers

Hi again,

I’ve been busy testing out the way you can install an operating system, mainly Linux at this stage, directly from booting up your computer/server.

Server

  • You need a server operating system, in this case I am using Fedora Core 6 – but I have also applied the principles to Ubuntu, capable of running DHCP and TFTP services.
  • Enough hard drive space for the server operating system and also enough space to store the contents of the downloaded discs.

Client

  • The minimum requirement is a network card, NIC, with a network boot ROM on and a hard drive with enough space for an operting sytstem of cours.

General Connections

  • A network switch or hub is recommended, although a cross-over cable would suffice (and proably be fairly quick).

So, now onto the specific server requirements…

  1. Download Fedora Core 6 here.
  2. Burn the discs and install a minimum setup – this should help.
  3. create a folder /Fedora and copy the dics 1 contents into this folder.
  4. copy the contents of the directories Fedora/RPMS from each additional disc into the newly created folder /Fedora/RPMS/ (no need to overwrite anything).
  5. make sure you have system-config-netboot/httpd/dhcp/tftp-server installed on the server system. use the command.

yum install -y system-config-netboot httpd dhcp tftp-server

DHCP.conf configuration/setup

  • Supply information so that the connecting machines know the network details as to whewre to find the operating system installlation files. Soedit the config file using:

nano /etc/dhcp.conf

A basic configuration follows:

ddns-update-style none;
option domain-name-servers 192.168.0.1;
default-lease-time 86400;
max-lease-time 604800;
authoritative;
subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.200 192.168.0.229;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.0.255;
option routers 192.168.0.1;
filename “pxelinux.0”;
next-server 192.168.0.100;
}

An explanation,taken from the source of this dhcp tutorial found here, follows:
I explain the configuration options here:
* ddns-update-style: You can tell the DHCP server to update a DNS server if the IP address of a server in your LAN has changed (because it has been assigned a different IP by DHCP). As we do not run servers in our LAN or always give them static IP addresses (which is a good idea for servers...) we don't want to update DNS records so we set this to none.
* option domain-name-servers: This tells the DHCP server which DNS servers it should assign to a client. You can specify more than one DNS server here, seperated by commas.
* default-lease-time, max-lease-time: A client can tell the DHCP server for how long it would like to get an IP address. If it doesn't do this, the server assigns an IP address for default-lease-time seconds; if it does, the server grants the requested time, but only up to max-lease-time seconds.
* authoritative: If this is not set this means that if a client requests an address that the server knows nothing about and the address is incorrect for that network segment, the server will _not_ send a DHCPNAK (which tells the client it should stop using the address.) We don't want this so we set authoritative.
* subnet: The subnet to use.
* netmask: The netmask to use.
* range: Tells the DHCP server from which range it can assign IP addresses to clients. In our example it's from 192.168.0.200 to 192.168.0.229 (30 IP addresses).
* option broadcast-address: The broadcast address to use.
* option routers: Tells the DHCP server the gateway address it should assign to requesting clients. In our case the gateway is 192.168.0.1.

The last two lines I have added myself,
filename "pxelinux.0";
next-server 192.168.0.100;

this tells the network installation machine to load the “pxelinux.0” image from the server 192.168.0.100.

Start the DHCP server using:

/etc/init.d/dhcpd start

Hopefully, no errors. now to ensure the dhcp server always starts after rebooting run:

chkconfig dhcpd on

Configure WebSite Alias

The install requires a running web-server from which the files are transferred to the new installation machine.

Therefore, we add an alias to the web-server, which we will call /fedora. The alias will point to the physical directory /Fedora. Open the web-server configuration file using:

nano /etc/httpd/conf/httpd.conf

and add the directory with its alias to the end of the file:

Allow from 192.168.0.0/24
AllowOverride None

alias /fedora /Fedora

Network Boot Configuration/Setup

To install our initial netboot install run:

system-config-netboot

and choose “Network Install”.

picture-3.png

Now add the name of your install – say “Fedora Core 6”.

Add the location of the install files, using 192.168.0.100/24 we add the line:

192.168.0.100/fedora

The location of our kickstart file will be at 192.168.0.100/fedora/ks.cfg

——————————————————————-

Hopefully, that should just about get you going with a great PXE nertwork install.

Please let me know if I can improve this tutorial or adapt it to suit your needs.

Costa

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