PXE 详解
PXE:全称为PrebooteXecution Environment ，可以基于网络给服务器安装系统，需要网卡支持网络启动引导，
一：需要准备的组件如下：
Yum install xinetd dhcpd tftp-server httpd syslinux
1、TFTP服务器；为客户端提供简单文件共享服务，比如启动内核、配置文件等等
2、DHCP服务器，作用为给客户端提供IP地址、掩码、网关、DNS、指定TFTP服务器地址
3、FTP或HTTP服务器，主要共享ks.cfg文件以及系统镜像
4、xinetd为tftp服务的守护进程
5、syslinux是一个安装包，主要提供/usr/share/syslinux/pxelinux.0文件
二：配置DHCP服务：
[root@localhost ~]# cat/etc/dhcp/dhcpd.conf
subnet 192.168.100.0 netmask 255.255.255.0 { #声明一个网段，不可是一个IP地址
range 192.168.100.10 192.168.100.100; #声明提供的IP地址范围
option domain-name-servers 192.168.100.1; #DNS地址
option routers 192.168.100.1; #网关
default-lease-time 600; #默认租约
next-server 192.168.100.1; #TFTP服务器地址
filename "pxelinux.0"; # pxe专用启动引导文件，直接存放在TFTP目录
max-lease-time 7200; #最长租约
}
三：准备tftp服务：
[root@localhost ~]# cat /etc/xinetd.d/tftp
# default: off
# description: The tftp server serves filesusing the trivial file transfer \
# protocol. The tftp protocol is oftenused to boot diskless \
# workstations, download configuration files to network-aware printers, \
# and to start the installation process for some operating systems.
service tftp
{
socket_type = dgram
protocol = udp
wait = yes
user = root
server =/usr/sbin/in.tftpd
server_args = -s/var/lib/tftpboot
disable = no #将disabled改为no
per_source = 11
cps = 100 2
flags = IPv4
[root@localhost ~]# /etc/init.d/xinetd restart #重启xinetd服务
停止 xinetd： [确定]
正在启动 xinetd： [确定]
四：准备ks.cfg文件（ks为文件名，可以自己定）
yum install system-config-kickstart
# system-config-kickstart
注：ks.xfg文件内容：
[root@localhost html]# cat ks.cfg
#platform=x86, AMD64, or Intel EM64T
#version=DEVEL
# Firewall configuration
firewall --disabled
# Install OS instead of upgrade
install
# Use network installation
url--url="http://192.168.100.1/centos6"
# Root password
rootpw --iscrypted$1$DoekR6CB$6acDFNurEa.MsWUlGmUJQ.
# System authorization information
auth --useshadow --passalgo=sha512
# Use text mode install
text
# System keyboard
keyboard us
# System language
lang en_US
# SELinux configuration
selinux --disabled
# Do not configure the X Window System
skipx
# Installation logging level
logging --level=info
# Reboot after installation
reboot
# System timezone
timezone Asia/Shanghai
# System bootloader configuration
bootloader --location=mbr
# Clear the Master Boot Record
zerombr
# Partition clearing information
clearpart --all --initlabel
# Disk partitioning information
part /boot --fstype="ext4"--size=200
part / --fstype="ext4" --grow--size=1
%packages
@additional-devel
@base
@basic-desktop
@desktop-debugging
@desktop-platform
@desktop-platform-devel
@development
@eclipse
@emacs
@fonts
@general-desktop
@graphical-admin-tools
@graphics
@hardware-monitoring
@input-methods
@internet-applications
@internet-browser
@java-platform
@legacy-x
@office-suite
@performance
@perl-runtime
@remote-desktop-clients
@ruby-runtime
@server-platform-devel
@system-management
@system-management-messaging-client
@system-management-snmp
@system-management-wbem
@technical-writing
@tex
@x11
%end
五：启动文件准备
/var/lib/tftpboot/pxelinux.cfg/vmlinuz #启动内核
initrd.img #系统初始化
boot.msg #主题
vesamenu.c32 #启动菜单主程序
splash.jpg #启动背景
pxelinux.0 #tftp引导文件
/var/lib/tftpboot/pxelinux.cfg/default
cp /var/www/html/centos6/images/pxeboot/{vmlinuz,initrd.img} /var/lib/tftpboot/
cp /var/www/html/centos6/isolinux/{boot.msg,vesamenu.c32,splash.jpg} /var/lib/tftpboot/
cp /usr/share/syslinux/pxelinux.0/var/lib/tftpboot/
mkdir /var/lib/tftpboot/isolinux.cfg
cp /mnt/isolinux/isolinux.cfg/var/lib/tftpboot/pxelinux.cfg/default
编辑default文件：
[root@localhost pxelinux.cfg]# cat default
default vesamenu.c32
#prompt 1
timeout 600
display boot.msg
menu background splash.jpg
menu title Welcome to CentOS 6.5!
menu color border 0 #ffffffff #00000000
menu color sel 7 #ffffffff #ff000000
menu color title 0 #ffffffff #00000000
menu color tabmsg 0 #ffffffff #00000000
menu color unsel 0 #ffffffff #00000000
menu color hotsel 0 #ff000000 #ffffffff
menu color hotkey 7 #ffffffff #ff000000
menu color scrollbar 0 #ffffffff #00000000
label linux
menu label ^Install or upgrade an existing system
menu default
kernel vmlinuz
append initrd=initrd.img ks=http://192.168.100.1/ks.cfg ksdevice=link #指定ks.cfg文件路径
label vesa
menu label Install system with ^basic video driver
kernel vmlinuz
append initrd=initrd.img xdriver=vesa nomodeset
label rescue
menu label ^Rescue installed system
kernel vmlinuz
append initrd=initrd.img rescue
label local
menu label Boot from ^local drive
localboot 0xffff
label memtest86
menu label ^Memory test
kernel memtest
append -
[root@localhost pxelinux.cfg]# mount /dev/cdrom /var/www/html/centos6/ #挂载光盘
mount: block device /dev/sr0 iswrite-protected, mounting read-only
[root@localhost html]# chmod 744 ks.cfg #给普通用户读权限
[root@localhost html]#/etc/init.d/httpd restart #重启http服务
停止 httpd： [确定]
正在启动 httpd：httpd: Could not reliably determine the server's fully qualifieddomain name, using localhost.localdomain for ServerName
[确定]
六：客户端安装测试：
如果安装过程中出现错误，会有相应提示，要根据提示进行排错