實驗拓撲圖

（1）本次基於VMware Workstation搭建一個四臺Linux（CentOS 7.5）系統所構成的一個伺服器叢集，其中兩臺nginx做前端排程伺服器（一臺為主機，另一臺為備機），另外兩臺作為真實的Web伺服器

　　（2）本次實驗設定了一個VIP（Virtual IP）為192.168.190.130，使用者只需要訪問這個IP地址即可獲得網頁服務。其中，nginx主機為192.168.190.133，備機為192.168.190.134。

一，配置nginx反向代理伺服器，在兩臺nginx上都做一遍下面的操作

    1，在http語句塊中定義排程規則
    vim /etc/nginx/nginx.conf
        http {
             .....

             upstream webser {
                        server 172.18.38.200:80;
                        server 172.18.38.201:80;
                  }

             .....
        }

    2，而後在server中呼叫
    vim /etc/nginx/conf.d/vhost.conf
        server {
                listen 172.18.38.99:80;
                server_name www.a.com;
                location / {
                        proxy_pass http://webser;
                }
        }
 

2，重啟nginx，使配置生效

    systemctl restart nginx

二，配置keepalived+nginx_master伺服器**

1，安裝keepalived

    yum install keepalived

2，修改keepalived配置檔案

! Configuration File for keepalived
    global_defs {
       notification_email {
         [email protected]
       }
       notification_email_from 
 
[email protected]
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id Lvs133
       vrrp_mcast_group4 224.1.1.1
    }

    vrrp_script chk_nginx {
    script "killall -0 nginx && exit 0 || exit 1"
    interval 1
    weight -30
    fall 2
    rise 2
    }
    vrrp_instance VI_1 {
        state MASTER
        interface ens33
        virtual_router_id 51
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 123456
        }
        virtual_ipaddress {
            192.168.190.130
        }
        track_script {
            chk_nginx
        }
    }
 

    關鍵配置：
        1，定義nginx健康檢查指令碼
        vrrp_script chk_nginx {
        script "killall -0 nginx && exit 0 || exit 1"
        interval 1     #以秒觸發一次
        weight -30     #nginx宕機就立馬減去有限級30
        fall 2         #檢查兩次如果都是宕機就表示nginx掛掉了
        rise 2         #宕機之後兩次檢查nginx是活著的就重新+30優先順序
        }

        2，呼叫
        track_script {
            chk_nginx

3，啟動keepalived

    systemctl  start keepalived
    systemctl enable keepalived

三，配置keepalived+nginx_slave伺服器

! Configuration File for keepalived
    global_defs {
       notification_email {
         [email protected]
       }
       notification_email_from [email protected]
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id Lvs134
       vrrp_mcast_group4 224.1.1.1
    }

    vrrp_script chk_nginx {
    script "killall -0 nginx && exit 0 || exit 1"
    interval 1
    weight -30
    fall 2
    rise 2
    }
    vrrp_instance VI_1 {
        state BACKUP
        interface ens33
        virtual_router_id 51
        priority 80
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 123456
        }
        virtual_ipaddress {
            192.168.190.130
        }
        track_script {
            chk_nginx
        }
    }

7，啟動keepalived

    systemctl  start keepalived
    systemctl enable keepalived

d

在113機子執行

systemctl stop keepalived