linux--nginx+keepalived 实现高可用

== 背景：==

server1          172.25.254.1         
server2          172.25.254.2
VIP              172.25.254.3   
真机              172.25.254.38       

在server1和server上源码编译nginx 并启动

在server1和server2中：

cd /usr/local/ngin/html
vi index.html

分别加入两台虚拟机的IP，以做区别。

然后分别安装keepalived

server1:

vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from keepalived@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script nginx_check {
   script "/etc/keeplived/nginx_check.sh"
   interval 2
   weight -20

}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.3
    }
}

server2:

vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from keepalived@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script nginx_check {
   script "/etc/keeplived/nginx_check.sh"
   interval 2
   weight -20

}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.3
    }
}

server1和server2同时:

systemctl start keepalived
systemctl status keepalived

此时，由于优先级的关系，server拿到VIP，开启服务。
测试：

当serevr1的keepalived停止之后，server2自动获得vip

当重新启动serevr1的keepalived之后，因为优先级的关系，发现serevr1自动接管资源。