* 在两台主备节点编辑keepalived配置文件


* 主节点主机上:

```

]# vim /etc/keepalived/keepalived.conf

------------------------------------------------------------------------------

global_defs {

    notification_email {

        root@localhost

    }

    notification_email_from kaadmin@magedu.com

    smtp_server 172.0.0.1

    smtp_connect_timeout 30

    router_id node1

    vrrp_mcast_group4 224.0.11.18

}



vrrp_script chk_down {

    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"

    interval 2

    weight -5

}



vrrp_script chk_httpd {

    script "killall -0 httpd"

    interval 2

    weight 5

}



vrrp_instance VI_1 {

    state MASTER

    interface eno16777736

    virtual_router_id 11

    priority 100

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass vHFHLlTA

    }


    virtual_ipaddress {

        172.18.11.7 dev eno16777736 label eno16777736:0

    }


    track_script {

        chk_down

    }


    notify_master "/etc/keepalived/notify.sh master"

    notify_backup "/etc/keepalived/notify.sh backup"

    notify_fault "/etc/keepalived/notify.sh fault"

}



vrrp_instance VI_2 {

    state BACKUP

    interface eno16777736

    virtual_router_id 12

    priority 98

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass RHFHLlTA

    }


    virtual_ipaddress {

        172.18.11.77 dev eno16777736 label eno16777736:1

    }

    track_script {

        chk_down

    }


    notify_master "/etc/keepalived/notify.sh master"

    notify_backup "/etc/keepalived/notify.sh backup"

    notify_fault "/etc/keepalived/notify.sh fault"

}

```



* 备节点主机上:

  ```

    ]# vim /etc/keepalived/keepalived.conf

    ---------------------------------------------------------------

    vrrp_instance VI_1 {

        state BACKUP

        interface eno16777736

        virtual_router_id 11

        priority 98

        advert_int 1

        authentication {

            auth_type PASS

            auth_pass vHFHLlTA

        }


        virtual_ipaddress {

            172.18.11.7 dev eno16777736 label eno16777736:0

        }


        track_script {

            chk_down

        }


        notify_master "/etc/keepalived/notify.sh master"

        notify_backup "/etc/keepalived/notify.sh backup"

        notify_fault "/etc/keepalived/notify.sh fault"

    }



    vrrp_instance VI_2 {

        state MASTER

        interface eno16777736

        virtual_router_id 12

        priority 100

        advert_int 1

        authentication {

            auth_type PASS

            auth_pass RHFHLlTA

        }


        virtual_ipaddress {

            172.18.11.77 dev eno16777736 label eno16777736:1

        }


        track_script {

            chk_down

        }


        notify_master "/etc/keepalived/notify.sh master"

        notify_backup "/etc/keepalived/notify.sh backup"

        notify_fault "/etc/keepalived/notify.sh fault"

    }



        主备节点都关闭keepalived服务;

    ]# systemctl stop keepalived.service


        先启动B备节点的keepalived服务;

    ]# systemctl start keepalived.service


    ]# ifconfig

        可见有两个VIP的地址都获得了即:

        172.18.11.7

        172.18.11.77

        此时,只有B节点,所以都当做主服务;


        再启动A节点的keepalived服务;

    ]# systemctl start keepalived.service


    ]# ifconfig

        则发现,获得了VIP为172.18.11.7;


        在A节点创建一个down文件

    ]# touch down


    ]# ifconfig

        此时VIP丢失;


        在B节点查看:

    ]# ifconfig

        获得成为了两个VIP的主用;


        同理,在B节点创建一个down文件,A节点会成为两个VIP的主用;

  ```

以上演示就是互为主备的高可用keepalived应用


**如果再加上vrrp_script的脚本监控nginx服务,于是这就双主模型的nginx节点;如果nginx工作在反代模式就是高可用调度器;把配置文件中httpd改为nginx,再调用即可;**