How to Install CentOS PXE server

A PXE install server allows your client computers to boot and install a Linux distribution over the network, without the need of burning Linux iso images, or human interaction. 

To install a PXE server, you will need the following components:

1. DHCP Server
2. TFTP Server
3. NFS/FTP/HTTPD server (to store installing files)

Step 1 - Install dhcp server

[root@server1 ~] # yum install dhcp

Dhcpd configuration file is located at /etc/dhcpd.conf. You can use /usr/share/doc/dhcp-3.0.5/dhcpd.conf.sample as a sample config, or you can use my config below as a base, make sure you change the subnet.

ddns-update-style interim;
not authoritative;
option domain-name "test.org";
option domain-name-servers 208.67.222.222, 208.67.220.220;
option subnet-mask 255.255.255.0;
subnet 172.20.30.0 netmask 255.255.255.0 {
   authoritative;
   range 172.20.30.10 172.20.30.90;
   option routers 172.20.30.254;
   allow unknown-clients;
   allow booting
   allow bootp
   next-server 172.20.30.100;
   filename "pxelinux.0";
} 

Step 2 - Install tftp-server

[root@server1 ~] # yum install tftp-server 

Edit /etc/xinetd.d/tftp and set disable to no.

service tftp
{
   socket_type = dgram
   protocol = udp
   wait = yes
   user = root
   server = /usr/sbin/in.tftpd
   server_args = -s /tftpboot
   disable = no
   per_source = 11
   cps = 100 2
   flags = IPv4
}

Step 3 - Create Network Install source

We can use three methods to store the installation files on the network and retrieve it when booting the client using PXE - nfs, ftp or http. I have chosen ftp:

[root@server1 ~] # yum install vsftpd

Public accessible ftp site is located in /var/ftp. Create installation tree in this folder.

[root@server1 ~] # mkdir -p /var/ftp/install/centos/i386/5.2
[root@server1 ~] # mkdir -p /var/ftp/install/debian/i386/4
[root@server1 ~] # mkdir -p /var/ftp/install/ubuntu-desktop/i386/8.10
[root@server1 ~] # mkdir -p /var/ftp/install/ubuntu-server/i386/8.10

If you have download dvd or cd iso files, you can mount them and copy the files:

[root@server1 ~] # mount -t iso9660 -o loop CentOS-5.2-i386-bin-DVD.iso /mnt/iso

Once mounted copy the installation files to /var/ftp/install/centos/i386/5.2. do this for each Linux distribution you want to include in your PXE server:

[root@server1 ~] # cp -avr /mnt/iso/* /var/ftp/install/centos/i386/5.2 

Step 4 Restart dhcpd, tftpd and vsftpd Services

[root@server1 ~] # /etc/init.d/dhcpd restart
[root@server1 ~] # /etc/init.d/xinetd restart
[root@server1 ~] # /etc/init.d/vsftpd restart 

and make the services persistent across reboots:

[root@server1 ~] # chkconfig --level 345 dhcpd on
[root@server1 ~] # chkconfig --level 345 vsftpd on 

tftpd server is managed by xinetd which is on after reboot by default.

Step 5 - Setup tftp network boot files

Create /tftpboot/images/ directory and populate it with the files necessary to start the installation program via PXE.

1. Copy the /usr/lib/syslinux/pxelinux.0 file installed by the syslinux package into /tftpboot/

[root@server1 tftpboot] # cp /usr/lib/syslinux/pxelinux.0 /tftpboot

2. Create /tftpboot/images/ directory tree and copy vmlinuz and inetrd files which are in the first cd/dvd or install-souce (/images/pxeboot/vmlinuz and /images/pxeboot/initrd).

[root@server1 tftpboot] # mkdir -p images/centos/i386/5.2
[root@server1 tftpboot] # cp /var/ftp/install/centos/i386/5.2/images/pxeboot/vmlinuz images/centos/i386/5.2
[root@server1 tftpboot] # cp /var/ftp/install/centos/i386/5.2/images/pxeboot/initrd images/centos/i386/5.2 

Step 6 - Create PXE Menu

Use the following steps to configure the PXE menu:

1. Copy menu.c32 file from /usr/lib/syslinux/menu.c32 into /tftpboot

[root@server1 ~] # cp /usr/lib/syslinux/menu.c32 /tftpboot 

2. Create /tftpboot/pxelinux.cnf directory

[root@server1 ~] # mkdir /tftpboot/pxelinux.cfg 

3. Create /tftpboot/pxelinux.cnf/default configuration file. The following is my default file configuration:

default menu.c32
prompt 0
timeout 300
MENU TITLE PXE Menu
LABEL CentoS 5.2 i386
MENU LABEL CentOS 5.2 i386
KERNEL images/centos/i386/5.2/vmlinuz append vga=normal initrd=images/centos/i386/5.2/initrd.img ramdisk_size=32768
method=ftp://172.20.30.100/install/centos/i386/5.2
LABEL Debian etch i386
MENU LABEL Debian etch i386
KERNEL images/debian/i386/4/vmlinuz append vga=normal initrd=images/debian/i386/4/initrd.gz ramdisk_size=32768
method=ftp://172.20.30.100/install/debian/i386/4
LABEL Ubuntu-Server 8.10
MENU LABEL Ubuntu-Server 8.10
KERNEL images/ubuntu-server/i386/8.10/linux append vga=normal initrd=images/ubuntu-server/i386/8.10/initrd.gz ramdisk_size=32768
LABEL Ubuntu-Desktop 8.10
MENU LABEL Ubuntu-Desktop 8.10
KERNEL images/ubuntu-desktop/i386/8.10/linux append vga=normal initrd=images/ubuntu-desktop/i386/8.10/initrd.gz ramdisk_size=32768 

tftp server files structure should look like this:

[root@server1 ~]# tree /tftpboot/
/tftpboot/
|-- images
| |-- centos
| | `-- i386
| | `-- 5.2
| | |-- initrd.img
| | `-- vmlinuz
| |-- debian
| | `-- i386
| | `-- 4
| | |-- initrd.gz
| | `-- vmlinuz
| |-- ubuntu-desktop
| | `-- i386
| | `-- 8.10
| | |-- initrd.gz
| | `-- linux
| `-- ubuntu-server
| `-- i386
| `-- 8.10
| |-- initrd.gz
| `-- linux
|-- menu.c32
|-- pxelinux.0
`-- pxelinux.cfg
|-- default

FTP files structure should look like this:

[root@server1 ~]# tree -L 3 /var/ftp
/install/
/var/ftp/install/
|-- centos
| `-- i386
| `-- 5.2
|-- debian
| `-- i386
| `-- 4
|-- ks
| `-- ks.cfg
|-- ubuntu-desktop
| `-- i386
| `-- 8.10
`-- ubuntu-server
`-- i386
`-- 8.10

Automating CenOS installation using kickstart

1. Install kickstart.

[root@server1 ~] # yum install system-config-kickstart 

2. Create kickstart file

Create kickstart file and place it on your installation source ftp site. Following is my kickstart configuration file that have been placed in ftp://172.20.30.100/install/ks/ks.cfg

#platform=x86, AMD64, or Intel EM64T
# System authorization information
auth --useshadow --enablemd5
# System bootloader configuration
bootloader --location=mbr
# Clear the Master Boot Record
zerombr
# Partition clearing information
clearpart --all --initlabel
# Use graphical install
graphical
# Firewall configuration
firewall --enabled --ssh
# Run the Setup Agent on first boot
firstboot --disable
# System keyboard
keyboard uk
# System language
lang en_GB
# Installation logging level
logging --level=info
# Use network installation
url --url=ftp://172.20.30.100/install/centos/i386/5.2
# Network information
network --bootproto=dhcp --device=eth0 --onboot=on
#network --bootproto=dhcp --device=eth1 --onboot=on
# Reboot after installation
reboot
#Root password
rootpw --iscrypted $1$dfadfaaffafarae1
# SELinux configuration
selinux --enforcing
# System timezone
timezone Europe/London
# Install OS instead of upgrade
install
# X Window System configuration information
xconfig --defaultdesktop=GNOME --depth=8 --resolution=800x600
# Disk partitioning information
part swap --bytes-per-inode=4096 --fstype="swap" --size=1000
part / --bytes-per-inode=4096 --fstype="ext3" --size=4000
%packages
@base

3. Modify /ftpboot/pxelinux.cfg/default

Edit /ftpboot/pxelinux.cfg/default file and add ks parameter.

LABEL CentoS 5.2 i386
MENU LABEL CentOS 5.2 i386
KERNEL images/centos/i386/5.2/vmlinuz
append vga=normal initrd=images/centos/i386/5.2/initrd.img ramdisk_size=32768
ks=ftp://172.20.30.100/install/ks/ks.cfg 

1 comment:

  1. I want to install CentOS PXE Server, thanks already to guide how to install.

    ReplyDelete