（1）两台服务器
（2）在两台服务器安装nginx
（3）在两台服务器安装keepalived
yum install keepalived -y
安装之后，在etc里面生成目录keepalived，有文件keepalived.conf

（1）修改主服务器keepalived.conf

vrrp_script chk_http_port {
	script "/usr/local/src/nginx_check.sh"
	interval 2   #(检测脚本的执行间隔)
	weight 2
}

vrrp_instance VI_1 {
    state MASTER  # 如果是备份服务器的话将MASTER改为BACKUP
    interface enp0s3   # 网卡,通过ifconfig获取
    virtual_router_id 51  #主、备机的virtual_router_id必须相同
    priority 100  #主、备机取不同的优先级，主机值较大，备份机值较小
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.168.200.16   # 虚拟IP地址
    }
}

（2）修改从服务器keepalived.conf
（3）在/usr/local/src添加检测脚本

#!/bin/bash
A='ps -C nginx -no-header |wc -l'
if [ $A -eq 0 ];then
	/usr/local/nginx/sbin/nginx
	sleep 2
	if [ '\ps -C nginx --no-header |wc -l' -eq 0 ];then
		killall keepalived
	fi
fi

（4）把两台服务器的nginx和keepalived启启来
启动nginx ./nginx
启动keepalived systemctl start keepalived.service

访问虚拟IP

将主服务器停掉以后访问虚拟IP