一键重装脚本

#!/bin/bash
#Net Reinstall Centos System

red='\033[0;31m'
green='\033[0;32m'
yellow='\033[0;33m'
plain='\033[0m'
nicCard=$(ls /sys/class/net)
nicCard=(${nicCard})
d0Str='$0'
nicCardName=""
vnc_password=""
repo_url=""
ipaddr=""
gateway=""
netmask=""
bootRoot=""

run_script() {
	if [ -f "/boot/initrd79.img" ]; then
		rm -rf /boot/initrd79.img
	fi
	wget -P /boot/ ${repo_url}images/pxeboot/initrd.img -O /boot/initrd79.img >/dev/null
	if [ -f "/boot/vmlinuz79" ]; then
		rm -rf /boot/vmlinuz79
	fi
	wget -P /boot/ ${repo_url}images/pxeboot/vmlinuz -O /boot/vmlinuz79 >/dev/null
	startDiskPart=$(cat /boot/grub2/grub.cfg | grep "set root" | head -n 1 | awk -F \' '{print $2}')
	startDiskType=$(df -T /boot | awk '{print $2}' | sed -n '2p')
	if [ "ext4" = "${startDiskType}" -o "ext3" = "${startDiskType}" ]; then
		startDiskType="ext2"
	fi
	cat <<EOF >/etc/grub.d/40_custom
#!/bin/sh
exec tail -n +3 ${d0Str}
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'NetInstall' {
        load_video
        set gfxpayload=keep
        insmod gzio
        insmod part_msdos
        insmod ${startDiskType}
        set root='${startDiskPart}'
 
        linux16 ${bootRoot}/vmlinuz79 inst.vnc inst.vncpassword=${vnc_password} inst.headless ip=${ipaddr}::${gateway}:${netmask}::${nicCardName}:none nameserver=223.5.5.5 inst.repo=${repo_url} inst.lang=en_US inst.keymap=us
        initrd16 ${bootRoot}/initrd79.img
}
EOF
	if [ -f "/boot/efi/EFI/centos/grub.cfg" ]; then
		grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
	fi
	if [ -f "/boot/grub2/grub.cfg" ]; then
		grub2-mkconfig -o /boot/grub2/grub.cfg
	fi
	#awk -F\' '$1=="menuentry " {print $2}' /etc/grub2.cfg
	#grub2-editenv list
	grub2-reboot NetInstall
	sleep 10
	reboot
}

input_nic() {
	bootRoot=$(cat /boot/grub2/grub.cfg | grep "linux16" | head -n 1)
	bootRoot=${bootRoot#*/}
	bootRoot=${bootRoot:0:4}
	if [ "boot" = "${bootRoot}" ]; then
		bootRoot="/boot"
	else
		bootRoot=""
	fi
	while true; do
		for ((i = 1; i <= ${#nicCard[@]}; i++)); do
			local_p="${nicCard[$i - 1]}"
			echo -e "${green}${i}${plain}) ${local_p}"
		done
		read -p "请输入主网卡序号[默认 1]:" input_nic_no
		[ -z "$input_nic_no" ] && input_nic_no=1
		expr ${input_nic_no} + 1 &>/dev/null
		if [ $? -ne 0 ]; then
			echo -e "[${red}错误:${plain}] 请输入一个数字"
			continue
		fi
		if [[ "$input_nic_no" -lt 1 || "$input_nic_no" -gt ${#nicCard[@]} ]]; then
			echo -e "[${red}错误：${plain}] 请输入一个数字 1 - ${#nicCard[@]}"
			continue
		fi
		nicCardName=${nicCard[$input_nic_no - 1]}
		break
	done
	read -p "请输入 VNC 密码[6 位+][默认密码 tg_jockerli]:" input_passwd
	[ -z "${input_passwd}" ] && input_passwd="tg_jockerli"
	vnc_password=${input_passwd}
	read -p "请输入 repo 地址[建议使用默认直接回车]:" input_repo
	[ -z "${input_repo}" ] && input_repo="http://mirrors.aliyun.com/centos/7.9.2009/os/x86_64/"
	repo_url=${input_repo}
	gateway=$(route -n | grep ${nicCardName} | grep UG | awk '{print $2}')
	ipaddr=$(ifconfig ${nicCardName} | grep "inet" | awk -F " " '{print $2}' | head -n 1)
	netmask=$(ifconfig ${nicCardName} | grep "inet" | awk -F " " '{print $4}' | head -n 1)
	#ipaddr=$(ip route get 1 | awk '{print $NF;exit}')
	#netmask=$(ip -o -f inet addr show | awk '/scope global/{sub(/[^.]+\//,"0/",$4);print $4}' | head -1 | awk -F '/' '{print $2}')
	#gateway=$(ip route | grep default | awk '{print $3}')
	echo
	echo "---------------------------"
	echo -e "${green}网    卡 ${plain}= ${green}${nicCardName}${plain}"
	echo -e "${green}IP  地址 ${plain}= ${green}${ipaddr}${plain}"
	echo -e "${green}网    关 ${plain}= ${green}${gateway}${plain}"
	echo -e "${green}掩    码 ${plain}= ${green}${netmask}${plain}"
	echo "---------------------------"
	echo -e "${green}VNC URL ${plain}= ${green}${ipaddr}:1${plain}"
	echo "---------------------------"
	echo -e "${green}VNC 密码 ${plain}= ${green}${vnc_password}${plain}"
	echo -e "${yellow}VNC 密码确保在 6 位以上！并且不包含特殊字符！${plain}"
	echo "---------------------------"
	echo -e "${green}repo 地址 ${plain}= ${green}${repo_url}${plain}"
	echo "---------------------------"
	echo -e "注意：${yellow}VNC 只能在脚本运行完等待数分钟可用${plain}"
	echo -e "     ${yellow}请确保服务商防火墙端口[1]为开放状态${plain}"
	echo
	read -p "回车开始运行脚本；ctrl + c 取消本次操作" input_read
	run_script
}

init() {
	if [ ! -f "/usr/bin/wget" ]; then
		yum -y install wget >/dev/null
	fi
	if [ ! -f "/usr/sbin/ifconfig" ]; then
		yum -y install net-tools >/dev/null
	fi
	input_nic
}
init

参考文档：
https://www.cnblogs.com/gleaners/p/5736521.html
http://www.danpros.com/2016/02/how-to-install-centos-7-remotely-using-vnc