简介

安装系统，老是要做一个U盘启动太麻烦，特别是机器多了，老是拿U盘插来插去的麻烦。

可以利用PXE启动，从网卡启动，加载安装程序就可以开始安装了。

启动过程简介

1. pxe启动通过dhcpd获取ip
2. tftp获取pxelinux.0程序
3. http服务提供文件服务来安装repo源

安装工具

通过网络安装就需要安装一些网络服务。

dnf -y install tftp-server dhcp-server   httpd syslinux rsync
systemctl enable tftp dhcpd httpd --now

ISO镜像

ISO镜像有所有安装需要的文件，通过httpd提供安装文件下载。

mount /dev/sr0   /mnt
mkdir -p /var/www/html/pub
rsync -avP /mnt   /var/www/html/pub

pxelinux.0

pxelinux.0可以启动一个简单的内核，然后通过这个简单的内核来加载安装程序。

syslinux提供了pxelinux.0程序，直接复制到tftp服务目录

 cp /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/

pxelinux 默认配置append initrd=initrd.img inst.repo=http://192.168.122.12/pub，如果要使用kickstart自动安装需要指定inst.ks=http://192.168.122.12/ks/ks.cfg

mkdir -p /var/lib/tftpboot/pxelinux.cfg
cat > /var/lib/tftpboot/pxelinux.cfg/default <<EOF
default vesamenu.c32
timeout 600

display boot.msg

# Clear the screen when exiting the menu, instead of leaving the menu displayed.
# For vesamenu, this means the graphical background is still displayed without
# the menu itself for as long as the screen remains in graphics mode.
menu clear
menu background splash.png
menu title PXE install basic Rocky Linux 9.3
menu vshift 8
menu rows 18
menu margin 8
#menu hidden
menu helpmsgrow 15
menu tabmsgrow 13

# Border Area
menu color border * #00000000 #00000000 none

# Selected item
menu color sel 0 #ffffffff #00000000 none

# Title bar
menu color title 0 #ff7ba3d0 #00000000 none

# Press [Tab] message
menu color tabmsg 0 #ff3a6496 #00000000 none

# Unselected menu item
menu color unsel 0 #84b8ffff #00000000 none

# Selected hotkey
menu color hotsel 0 #84b8ffff #00000000 none

# Unselected hotkey
menu color hotkey 0 #ffffffff #00000000 none

# Help text
menu color help 0 #ffffffff #00000000 none

# A scrollbar of some type? Not sure.
menu color scrollbar 0 #ffffffff #ff355594 none

# Timeout msg
menu color timeout 0 #ffffffff #00000000 none
menu color timeout_msg 0 #ffffffff #00000000 none

# Command prompt text
menu color cmdmark 0 #84b8ffff #00000000 none
menu color cmdline 0 #ffffffff #00000000 none

# Do not display the actual menu unless the user presses a key. All that is displayed is a timeout message.

menu tabmsg Press Tab for full configuration options on menu items.

menu separator # insert an empty line
menu separator # insert an empty line

label linux
  menu label ^Install Rocky Linux 9.3 From kickstart
  kernel vmlinuz
  #append initrd=initrd.img inst.ks=http://192.168.122.12/ks/ks.cfg
  append initrd=initrd.img inst.repo=http://192.168.122.12/pub

label memtest
  menu label Run a ^memory test
  text help
        If your system is having issues, a problem with your
        system's memory may be the cause. Use this utility to
        see if the memory is working correctly.
  endtext
  kernel memtest

menu separator # insert an empty line

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

menu separator # insert an empty line
menu separator # insert an empty line

menu end
EOF

DHCP分配IP

dhcp需要配置分发的网段、网关、tftp服务器、pxelinux在tftp服务的位置

cat >>  /etc/dhcp/dhcpd.conf  <<EOF
subnet 192.168.122.0 netmask 255.255.255.0 {
range 192.168.122.40 192.168.122.199;
option routers 192.168.122.1;
option subnet-mask 255.255.255.0;
default-lease-time 21600;
max-lease-time 43200;
next-server 192.168.122.12;
filename "/pxelinux.0";
}
EOF

重启服务

systemctl restart httpd tftp dhcpd

注意事项

1. 禁用selinux。
2. iptables或者firewalld要开放对应的端口，或者直接清空规则
3. 同一个网段里面只能有一个dhcp，不然指定的tftp-server配置就无法加载到

总结

为什么不用kickstart安装？

为了快速完成任务。机器配置不一样，手动安装可以灵活一点。当然，kickstart脚本写好就更方便了。