下載wget http://keepalived.org/software/keepalived-2.0.6.tar.gz

mkdir /usr/local/keepalived/

tar  -zxvf  keepalived-2.0.6.tar.gz  -C  /usr/local/keepalived

cd  /usr/local/keepalived/keepalived-2.0.6
./configure

make
make install
cp -r keepalived  /etc/init.d/keepalived
mkdir  /etc/keepalived/
cd /usr/local/keepalived/keepalived-2.0.6/keepalived/etc/keepalived
cp  keepalived.conf  /etc/keepalived/
cd /usr/local/keepalived/keepalived-2.0.6/keepalived/etc/sysconfig/
cp keepalived  /etc/sysconfig/keepalived
cp /usr/local/keepalived/keepalived-2.0.6/bin/keepalived /usr/sbin


vi  /etc/keepalived/keepalived.conf   #以下是配置的內容

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 101
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.67.100
    }
}

以上修改瞭如下三項
1.
priority 101	#Master值要大於Bakcup
2.更改網路介面 
vrrp_instance VI_1 中interface:eno16777736(ip addr命令中的網路) 
3.
192.168.67.100 是虛擬ip

啟動keepalived
service  keepalived  start或者systemctl start keepalived

備用排程伺服器 只有一項不同
 priority 100
同樣配置完畢後啟動keepalived

注意:
#vrrp_strict      #這個註釋掉，否則可能造成物理機的瀏覽器無法訪問應用

啟動keepalived  
service keepalived start
設定開機自啟動
systemctl  enable  keepalived.service
 

如果nginx死掉，虛擬ip不會自動切換，如果要nginx停止執行後虛擬ip自動切換，需要設定指令碼：

#增加keepalived配置檔案
vi  /etc/keepalived/keepalived.conf

#修改配置
! Configuration File for keepalived

global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from 
 
[email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}
			vrrp_script chk_nginx{
				script "/root/nginx_chk.sh"
			}

vrrp_instance VI_1 {
    state MASTER
    interface eno16777736
    virtual_router_id 51
    priority 101
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.43.66
    }
		    track_script{
			chk_nginx
		    }
}
#建立 vi /root/nginx_chk.sh，輸入指令碼
#!/bin/bash
if [ "$(ps aux | grep  "nginx: master process"|grep -v grep)" == "" ]
then
        #/etc/init.d/keepalived/keepalived  stop
        service keepalived  stop
fi