1, Introduction

1. What is PXE

• PXE, full name pre boot execution environment, pre boot execution environment
• The term PXE client refers to the role of the machine during PXE boot. A PXE client can be a server, laptop or other machine with PXE boot code (our computer's network card).

2. PXE working process

Here are the recommendations:
be careful:
1. In the later operation, you should check the system log in real time, and analyze and understand it with this figure!

2. Whether it's dhcp or other services, we deploy them on a virtual machine!

2, Realize network manual installation

1. System environment preparation

Objective: to achieve hundreds of blank servers and install the operating system!

# Turn off firewall
systemctl stop firewalld

# Turn off selinux
sed -i '/SELINUX/s/enforcing/disabled/g' /etc/selinux/config # restart
getenforce

#Virtual machine network card description
 This computer needs two network cards, one is NAT mode and the other is LAN section

Configure yum source:

cd /etc/yum.repos.d/
rm -f *
mount /dev/sr0 /mnt
vim /etc/yum.repos.d/base.repo
'
name=base
baseurl=file:///mnt/
gpgcheck=0
enabled=1
'

2. Install and configure dhcp service

// The ip address of the local intranet card is 192.168.1.201
yum install dhcp -y
[root@linux-node1 ~]# vim /etc/dhcp/dhcpd.conf
subnet 192.168.1.0 netmask 255.255.255.0 {
        range 192.168.1.1 192.168.1.200;
        option subnet-mask 255.255.255.0;
        default-lease-time 21600;
        max-lease-time 43200;
        next-server 192.168.1.201;
        filename "/pxelinux.0";
}
// Note: the dhcp server should be in an intranet environment with the virtual machine that needs to install the operating system, and there is no interference from other dhcp servers!

systemctl restart dhcpd

3. Install and configure tftp service

yum install tftp-server -y
[root@linux-node1 ~]# vim /etc/xinetd.d/tftp
service tftp
{
        socket_type             = dgram
        protocol                = udp
        wait                    = yes
        user                    = root
        server                  = /usr/sbin/in.tftpd
        server_args             = -s /var/lib/tftpboot // Specify the directory, keep the default, do not modify
        disable                 = no // From yes to no
        per_source              = 11
        cps                     = 100 2
        flags                   = IPv4
}

systemctl start tftp.socket
systemctl start tftp.service
netstat -luntp|egrep '69|67'

4. Install and configure httpd service

yum install httpd -y
sed -i '96i ServerName 127.0.0.1:80' /etc/httpd/conf/httpd.conf
systemctl restart httpd
mkdir /var/www/html/CentOS-7.6
cp -a /mnt/* /var/www/html/CentOS-7.6/ 
# Note that there are two other hidden files that have not been copied:
cp /mnt/.discinfo /var/www/html/CentOS-7.6/
cp /mnt/.treeinfo /var/www/html/CentOS-7.6/
# Previously, mount the image file of centos7 to / mnt. We need to copy the image file to httpd's publishing directory. Later, the virtual machine will find httpd to download

curl http://192.168.1.201/CentOS-7.6/ # See if httpd is successful!

5. Configure PXE boot program

(1) PXE boot configuration

Syslinux is a powerful boot loader and is compatible with various media. Syslinux is a small Linux operating system, its purpose is to simplify the time of the first installation of Linux, and to establish a repair or other special purpose boot disk. If you don't find pxelinux.0, you can install it.

yum install syslinux -y
cp /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/
cp -a /var/www/html/CentOS-6.7/isolinux/* /var/lib/tftpboot/
mkdir -p /var/lib/tftpboot/pxelinux.cfg
cp /var/www/html/CentOS-6.7/isolinux/isolinux.cfg /var/lib/tftpboot/pxelinux.cfg/default

(2) PXE configuration file default resolution

[root@linux-node1 ~]# vim /var/lib/tftpboot/pxelinux.cfg/default
label linux
   menu label ^Install CentOS 7
   kernel vmlinuz
   append initrd=initrd.img inst.stage2=http://192.168.1.201/CentOS-7.6/ quiet net.ifnames=0 biosdevname=0
// Among them“ net.ifnames=0  Biosdevname = 0 "these two kernel startup parameters are used to make the network card name ethN, rather than the default random name such as eno16777728.

6. Test manual network installation operating system

Because my computer is mac, I heard that lan section is needed for the internal network card of this computer, but my vmware fusion does not seem to have this network mode, so I adopted the host only mode, but there are problems here! This can only wait for a chance later, and then add to improve it!

(1) New blank virtual machine

(2) Start virtual machine

3, Realize the automatic installation of kickstart

1, ks.cfg Detailed explanation

ks.cfg The composition of the document is roughly divided into three sections

• Command segment

The configuration of keyboard type, language, installation method and other systems has required and optional options. If a required option is missing, the installation will be interrupted and the user will be prompted to select the option

• Package segment

 - %packages
 -@ groupname: Specifies the installed package group
 - package_name: specify the package to install
 - -package_name: specify packages not to be installed
 The software package installed by default during the installation process will automatically analyze the dependency when the software is installed.

• Script segment (optional)

1.% pre: command or script executed before system installation (few commands are supported because it only depends on boot image)
2.% post: command or script executed after system installation (all commands are basically supported)

2. Prepared by ks.cfg file

# Sir, make a password for backup
[root@linux-node1 ~]# grub-crypt
Password:123456
Retype password:123456
$6$X20eRtuZhkHznTb4$dK0BJByOSAWSDD8jccLVFz0CscijS9ldMWwpoCw/ZEjYw2BTQYGWlgKsn945fFTjRC658UXjuocwJbAjVI5D6/

[root@linux-node1 ~]# mkdir /var/www/html/ks_config
[root@linux-node1 ~]# vim /var/www/html/ks_config/CentOS-7.6-ks.cfg
# Kickstart Configurator for CentOS 7.6 by yao zhang
install
url --url="http://192.168.1.201/CentOS-7.6/"
text
lang en_US.UTF-8
keyboard us
zerombr
bootloader --location=mbr --driveorder=sda --append="crashkernel=auto rhgb quiet"
network --bootproto=dhcp --device=eth0 --onboot=yes --noipv6 --hostname=CentOS7
timezone --utc Asia/Shanghai
authconfig --enableshadow --passalgo=sha512
rootpw  --iscrypted $6$X20eRtuZhkHznTb4$dK0BJByOSAWSDD8jccLVFz0CscijS9ldMWwpoCw/ZEjYw2BTQYGWlgKsn945fFTjRC658UXjuocwJbAjVI5D6/
clearpart --all --initlabel
part /boot --fstype=ext4 --asprimary --size=200
part swap --size=1024
part / --fstype=ext4 --grow --asprimary --size=200
firstboot --disable
selinux --disabled
firewall --disabled
logging --level=info
reboot
%packages
@base
@compat-libraries
@debugging
@development
tree
nmap
sysstat
lrzsz
dos2unix
telnet
%post
wget -O /tmp/optimization.sh http://192.168.1.201/ks_config/optimization.sh &>/dev/null
/bin/sh /tmp/optimization.sh
%end

3. Power on Optimization script

[root@linux-node1 ~]# vim /var/www/html/ks_config/optimization.sh
#!/bin/bash
##############################################################
# File Name: /var/www/html/ks_config/optimization.sh
# Version: V1.0
# Author: yao zhang
# Organization: www.zyops.com
# Created Time : 2015-12-03 15:23:08
# Description: Linux system initialization
##############################################################
. /etc/init.d/functions
Ip=192.168.1.201
Port=80
ConfigDir=ks_config
# Judge Http server is ok?
PortNum=`nmap $Ip  -p $Port 2>/dev/null|grep open|wc -l`
[ $PortNum -lt 1 ] && {
        echo "Http server is bad!"
        exit 1
}
# Defined result function
function Msg(){
        if [ $? -eq 0 ];then
          action "$1" /bin/true
        else
          action "$1" /bin/false
        fi
}
# Defined IP function
function ConfigIP(){
        Suffix=`ifconfig eth0|awk -F "[ .]+" 'NR==2 {print $6}'`
        cat >/etc/sysconfig/network-scripts/ifcfg-eth0 <<-END
        DEVICE=eth0
        TYPE=Ethernet
        ONBOOT=yes
        NM_CONTROLLED=yes
        BOOTPROTO=none
        IPADDR=10.0.0.$Suffix
        PREFIX=24
        GATEWAY=10.0.0.2
        DNS1=10.0.0.2
        DEFROUTE=yes
        IPV4_FAILURE_FATAL=yes
        IPV6INIT=no
        NAME="System eth0"
        END
        Msg "config eth0"
}
# Defined Yum source Functions
function yum(){
        YumDir=/etc/yum.repos.d
        [ -f "$YumDir/CentOS-Base.repo" ] && cp $YumDir/CentOS-Base.repo{,.ori} 
        wget -O $YumDir/CentOS-Base.repo http://$Ip:$Port/$ConfigDir/CentOS-Base.repo &>/dev/null &&\
        wget -O $YumDir/epel.repo http://$Ip:$Port/$ConfigDir/epel.repo &>/dev/null &&\
        Msg "YUM source"
}
# Defined Hide the system version number Functions
function HideVersion(){
        [ -f "/etc/issue" ] && >/etc/issue
        Msg "Hide issue" 
        [ -f "/etc/issue.net" ] && > /etc/issue.net
        Msg "Hide issue.net"
}
# Defined OPEN FILES Functions
function openfiles(){
        [ -f "/etc/security/limits.conf" ] && {
        echo '*  -  nofile  65535' >> /etc/security/limits.conf
        Msg "open files"
        }
}
# Defined Kernel parameters Functions
function kernel(){
        KernelDir=/etc
        [ -f "$KernelDir/sysctl.conf" ] && /bin/mv $KernelDir/sysctl.conf{,.ori}
        wget -O $KernelDir/sysctl.conf http://$Ip:$Port/$ConfigDir/sysctl.conf &>/dev/null
        Msg "Kernel config"
}
# Defined System Startup Services Functions
function boot(){
        for oldboy in `chkconfig --list|grep "3:on"|awk '{print $1}'|grep -vE "crond|network|rsyslog|sshd|sysstat"` 
          do 
           chkconfig $oldboy off
        done
        Msg "BOOT config"
}
# Defined Time Synchronization Functions
function Time(){
        echo "#time sync by zhangyao at $(date +%F)" >>/var/spool/cron/root
        echo '*/5 * * * * /usr/sbin/ntpdate time.nist.gov &>/dev/null' >>/var/spool/cron/root
        Msg "Time Synchronization"
}
# Defined main Functions
function main(){
        ConfigIP
        yum
        HideVersion
        openfiles
        kernel
        boot
        Time
}
main

4. Integrate edit default profile

# Thinnest configuration
[root@linux-node1 ~]# vim /var/lib/tftpboot/pxelinux.cfg/default
default ks
prompt 0
label ks
  kernel vmlinuz
  append initrd=initrd.img ks=http://192.168.1.201/ks_config/CentOS-7.6-ks.cfg ksdevice=eth0 # Tell setup ks.cfg Where is the file
# ksdevice=eth0 means that when the client has multiple network cards, you need to install them from eth1 to achieve automation. If not specified, the system will let you choose when you install them, which is not called full automation.

5. Unattended automatic installation

Turn on the system and go out for a drink. After a meeting, the system will be installed_