pxe自动化安装系统

pxe自动化安装，所需要的服务有：dhcp服务器，tftp服务器，http服务器

pxe自动化安装，所需要的包组及相关安装文件有：syslinux以及自动化安装系统所需的应答文件selinux

实验说明：

本次实验以一台CentOS7作为dhcp服务器，tftp服务器，以及http服务器向本网段内的主机提供自动化安装CentOS系统

准备工作：

主机 系统 IP
CentOS7 CentOS7 192.168.73.120

一、安装dhcp服务、tftp-server服务、httpd服务及syslinux包组

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[root@centos7 ~]# yum install dhcp tftp-server httpd syslinux -y

二、创建应答文件

1.使用system-config-kickstart生成ks6.cfg

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[root@centos7 ~]# system-config-kickstart
[root@centos7 ~]# vim ks6.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://192.168.73.120/centos/6/os/x86_64"
# Root password
rootpw --iscrypted $1$6oVXZR1R$QOASc6inirmHCZmQ.W9Hg0
# 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
# Network information
network  --bootproto=dhcp --device=eth0 --onboot=on
# 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" --size=20000
part swap --fstype="swap" --size=1024

%packages
@core

%end

2.复制ks6.cfg为ks7.cfg，并修改部分参数

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[root@centos7 ~]# cp ks6.cfg ks7.cfg
[root@centos7 ~]# vim ks7.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://192.168.73.120/centos/7/os/x86_64"    #将url改为7的url
# Root password
rootpw --iscrypted $1$6oVXZR1R$QOASc6inirmHCZmQ.W9Hg0
# 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
# Network information
network  --bootproto=dhcp --device=ens33 --onboot=on      #将网卡名修改为ens33
# 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" --size=20000
part swap --fstype="swap" --size=1024

%packages
@core

%end

三、配置httpd服务

1.创建http目录

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[root@centos7 ~]# mkdir -pv /var/www/html/{centos/{6,7}/os/x86_64,ksdir}
mkdir: created directory ‘/var/www/html/centos’
mkdir: created directory ‘/var/www/html/centos/6’
mkdir: created directory ‘/var/www/html/centos/6/os’
mkdir: created directory ‘/var/www/html/centos/6/os/x86_64’
mkdir: created directory ‘/var/www/html/centos/7’
mkdir: created directory ‘/var/www/html/centos/7/os’
mkdir: created directory ‘/var/www/html/centos/7/os/x86_64’
mkdir: created directory ‘/var/www/html/ksdir’

2.将CentOS6及7的光盘文件挂在至相关的目录下(工作中可以直接将光盘镜像复制至目录下)

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[root@centos7 ~]# lsblk | grep sr
sr0     11:0    1   10G  0 rom  /mnt
sr1     11:1    1  3.7G  0 rom  
[root@centos7 ~]# mount /dev/sr0 /var/www/html/centos/7/os/x86_64/
mount: /dev/sr0 is write-protected, mounting read-only
[root@centos7 ~]# mount /dev/sr1 /var/www/html/centos/6/os/x86_64/
mount: /dev/sr1 is write-protected, mounting read-only
[root@centos7 ~]# lsblk | grep sr
sr0     11:0    1   10G  0 rom  /var/www/html/centos/7/os/x86_64
sr1     11:1    1  3.7G  0 rom  /var/www/html/centos/6/os/x86_64

3.将准备好的应答文件复制至目录下

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[root@centos7 ~]# cp ks6.cfg /var/www/html/ksdir
[root@centos7 ~]# cp ks7.cfg /var/www/html/ksdir

4.启动httpd服务，并设置为开机自动启动

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[root@centos7 ~]# systemctl start httpd
[root@centos7 ~]# systemctl enable httpd

四、配置tftp服务器

1.在tftp工作目录下创建出相关的文件目录

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[root@centos7 ~]# mkdir -pv /var/lib/tftpboot/{kernel{6,7},pxelinux.cfg}
mkdir: created directory ‘/var/lib/tftpboot/kernel6’
mkdir: created directory ‘/var/lib/tftpboot/kernel7’
mkdir: created directory ‘/var/lib/tftpboot/pxelinux.cfg’

2.将centos6和centos7的内核及虚拟文件系统复制至tftp工作目录下的相对应kernel目录中

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[root@centos7 tftpboot]# cd /var/lib/tftpboot/kernel6
[root@centos7 kernel6]# cp /var/www/html/centos/6/os/x86_64/isolinux/vmlinuz .
[root@centos7 kernel6]# cp /var/www/html/centos/6/os/x86_64/isolinux/initrd.img .
[root@centos7 kernel6]# cd /var/lib/tftpboot/kernel7
[root@centos7 kernel7]# cp /var/www/html/centos/7/os/x86_64/isolinux/vmlinuz .
[root@centos7 kernel7]# cp /var/www/html/centos/7/os/x86_64/isolinux/initrd.img .

3.复制启动相关的文件至tftp工作目录

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[root@centos7 kernel7]# cd /var/lib/tftpboot/
[root@centos7 tftpboot]# cp /usr/share/syslinux/menu.c32 .
[root@centos7 tftpboot]# cp /usr/share/syslinux/pxelinux.0 .

4.复制光盘上的菜单文件至/var/lib/tftpboot/pxelinux.cfg目录下改名为default，修改此文件

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[root@centos7 tftpboot]# cp /var/www/html/centos/7/os/x86_64/isolinux/isolinux.cfg /var/lib/tftpboot/pxelinux.cfg/default
[root@centos7 tftpboot]# vim /var/lib/tftpboot/pxelinux.cfg/default
default menu.c32            #将此行改为menu.c32
timeout 600

menu title CentOS install

label linux 6
  menu label Install CentOS ^6
  kernel kernel6/vmlinuz    #此处为centos6内核所在的路径
  append initrd=kernel6/initrd.img ks=http://192.168.73.120/ksdir/ks6.cfg               #指定KS文件在网络中的位置

label linux 7
  menu label Install CentOS ^7
  kernel kernel7/vmlinuz    #此处为centos7内核所在的路径
  append initrd=kernel7/initrd.img ks=http://192.168.73.120/ksdir/ks7.cfg               #指定KS文件在网路中的位置

label local
  menu label Boot from ^local drive
  localboot 0xffff

5.查看下目录结构

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[root@centos7 tftpboot]#tree
.
├── centos6
│   ├── initrd.img
│   └── vmlinuz
├── centos7
│   ├── initrd.img
│   └── vmlinuz
├── menu.c32
├── pxelinux.0
└── pxelinux.cfg
    └── default

6.启动tftp服务，并设置为开机启动

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[root@centos7 ~]# systemctl start tftp
[root@centos7 ~]# systemctl enable tftp

五、配置dhcp服务

1.由于dhcpd默认的配置文件为空，此处将dhcpd的样板配置文件复制后加以修改

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[root@centos7 ~]# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf
cp: overwrite ‘/etc/dhcp/dhcpd.conf’? y

2.配置dhcp服务

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[root@centos7 ~]# vim /etc/dhcp/dhcpd.conf
# option definitions common to all supported networks...
option domain-name "mylinuxops.com";                #指定预添加域名
option domain-name-servers 114.114.114.114;         #指定DNS服务器

default-lease-time 6000;
max-lease-time 72000;

...中间省略...

# No service will be given on this subnet, but declaring it helps the 
# DHCP server to understand the network topology.

#subnet 10.152.187.0 netmask 255.255.255.0 {    #注释
#}                                              #注释

# This is a very basic subnet declaration.

subnet 192.168.73.0 netmask 255.255.255.224 {
  range 192.168.73.1 192.168.73.100;        #指定dhcp地址池
  option routers 192.168.73.254;            #指定网关
  filename "pxelinux.0";                    #指定启动文件
  next-server 192.168.73.120;               #指定tftp服务器路径
}

3.启动dhcp服务器，并设置为开机自动启动

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[root@centos7 ~]# systemctl start dhcpd
[root@centos7 ~]# systemctl enable dhcpd
Created symlink from /etc/systemd/system/multi-user.target.wants/dhcpd.service to /usr/lib/systemd/system/dhcpd.service.

写在最后

以上为pxe自动化安装的全过程，有几点细节需要注意：

1.所有服务部署完毕，进行测试之前，确保网络中没有其他的DHCP服务，避免产生干扰。

2.centos7在自动化安装时需要1G以上的内存空间。

3.安装时注意物理磁盘的大小以及ks文件中的磁盘大小 ，确保有足够的空间进行安装。