PXE boot notes

pxe boot client
http://www.linuxreaders.com/2010/06/24/pxe-boot-ubuntu-10-04/
pxe boot server (centos version)
http://www.linuxreaders.com/2010/06/15/pxe-boot-server-on-centos/

Client

This works with latest version – ubuntu 10.10.
Once you are done setting-up PXE Server, you might need few OS booting from network / pxe for rescue purpose.
Ubuntu 10.04 can be configured to boot from network & can be used for system rescue.
Following is the procedure to boot Ubuntu 10.04 using PXE.
Mount ubuntu live iso on pxe server
mkdir /mnt/iso
mount ubuntu-10.04-desktop-i386.iso /mnt/iso
Create nfs share for ubuntu & copy all the content of live cd to it
mkdir /nfs-share/ubuntu -p
cp -rfva /mnt/iso/* /nfs-share/ubuntu/
cp -rfva /mnt/iso/.disk /nfs-share/ubuntu/
Enter following in /etc/exports
/nfs-share/ubuntu/ *(no_root_squash,rw,async)
Apply changes
exportfs -rv
Enter following in /tftpboot/pxelinux.cfg/default

LABEL Ubuntu-10.04
kernel /tftpboot/images/ubuntu/vmlinuz
append boot=casper netboot=nfs nfsroot=NFSSERVER:/nfs-share/ubuntu initrd=/tftpboot/images/ubuntu/initrd.lz

Copy initrd and vmlinuz from Ubuntu live cd to tftpboot
cd /nfs-share/ubuntu/casper
cp vmlinuz initrd.lz /tftpboot/images/ubuntu/

Server
This post will be helpful for linux admins who frequently installs diff linux os. PXE boot is one of the best option to start linux installation & for rescue of the other failed systems. we are using CentOS as pxe boot server.
install syslinux & tftp-server

yum install tftp-server syslinux -y

enable syslinux at boot time.

vi /etc/xinetd.d/tftp and change disable to ‘no’
disable = no
service xinetd restart
chkconfig xinetd on

Copy needed files from syslinux to the tftpboot directory

cp /usr/lib/syslinux/pxelinux.0 /tftpboot
cp /usr/lib/syslinux/menu.c32 /tftpboot
cp /usr/lib/syslinux/memdisk /tftpboot
cp /usr/lib/syslinux/mboot.c32 /tftpboot
cp /usr/lib/syslinux/chain.c32 /tftpboot

Create a base directory for images. Create directories for each CentOS release you are supporting.

mkdir -p /tftpboot/images/centos/i386/5.4
cp /tmp/dvd-centos-54/images/pxeboot/vmlinuz /tftpboot/images/centos/i386/5.4/
cp /tmp/dvd-centos-54/images/pxeboot/initrd.img /tftpboot/images/centos/i386/5.4/

Configure dhcp-server. Add this to your existing or new /etc/dhcpd.conf.
Note: xxx.xxx.xxx.xxx is the IP address of your PXE server
How to configure dhcp server on centos

allow booting;
allow bootp;
option option-128 code 128 = string;
option option-129 code 129 = text;
next-server xxx.xxx.xxx.xxx;
filename “/pxelinux.0″;
service dhcpd restart

Create the directory for your PXE menus

mkdir /tftpboot/pxelinux.cfg

Sample config file
vi /tftpboot/pxelinux.cfg/default

default menu.c32
 
 
prompt 0
timeout 50
ONTIMEOUT localboot
 
MENU TITLE PXE Menu
 
LABEL localboot
MENU LABEL Boot From Hard Disk
LOCALBOOT  0
 
LABEL CentoS 5.4 i386 Installer
MENU LABEL CentOS 5.4 i386 Installer
KERNEL images/centos/i386/5.4/vmlinuz
append vga=normal initrd=images/centos/i386/5.4/initrd.img ramdisk_size=32768
 
LABEL CentoS 5.5 i386 Installer
MENU LABEL CentOS 5.5 i386 Installer
KERNEL images/centos/i386/5.5/vmlinuz
append vga=normal initrd=images/centos/i386/5.5/initrd.img ramdisk_size=32768