5.Lvs+Keepalived健康检查

1. Nginx+keepalived对后端服务器心跳检查(需要自定义脚本)

原理：Keepalived并不跟nginx耦合，它俩完全不是一家人但是keepalived提供一个机制：让用户自定义一个shell脚本去检测用户自己的程序，返回状态给keepalived就可以了

#MASTER节点

global_defs {
}

vrrp_script chk_health {
    script "[[ `ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"
    interval 1    #每隔1秒执行上述的脚本，去检查用户的程序ngnix
    weight -2
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 1
    priority 100
    advert_int 2
    authentication {
        auth_type PASS
        auth_pass 1111
    }

    track_script {
        chk_health
    }

    virtual_ipaddress {
        10.0.0.10/24
    }

    notify_master "/usr/local/keepalived/sbin/notify.sh master"
    notify_backup "/usr/local/keepalived/sbin/notify.sh backup"
    notify_fault "/usr/local/keepalived/sbin/notify.sh fault"
}

#添加切换通知脚本：vi /usr/local/keepalived/sbin/notify.sh

#!/bin/bash

case "$1" in
    master)
        /usr/local/nginx/sbin/nginx
        exit 0
    ;;
backup)
        /usr/local/nginx/sbin/nginx -s stop
        /usr/local/nginx/sbin/nginx
        exit 0
    ;;
    fault)
        /usr/local/nginx/sbin/nginx -s stop
        exit 0
    ;;
    *)
        echo 'Usage: notify.sh {master|backup|fault}'
        exit 1
    ;;
esac

#添加执行权限：chmod +x /usr/local/keepalived/sbin/notify.sh

global_defs {
}

vrrp_script chk_health {
    script "[[ `ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"
    interval 1
    weight -2
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 1
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

    track_script {
        chk_health
    }

    virtual_ipaddress {
        10.0.0.10/24
    }
    
    notify_master "/usr/local/keepalived/sbin/notify.sh master"
    notify_backup "/usr/local/keepalived/sbin/notify.sh backup"
    notify_fault "/usr/local/keepalived/sbin/notify.sh fault"
}

#在第二台机器上添加notify.sh脚本

#分别在两台机器上启动keepalived

service keepalived start

chkconfig keepalived on

2. Lvs+keepalived对后端服务器心跳检查(不需要自定义脚本)

　　1. 在两台（192.168.232.201和192.168.232.205） Lvs转发服务器上安装ipvsadm和Keepalived：yum -y install ipvsadm/keepalived 

　　 2. 修改配置文件：vi  /etc/keepalived/keepalived.conf

　　　　主机：Lvs+keepalived（MASTER）

global_defs {
   #指定keepalived在发生切换时需要发送email到的对象
   notification_email { 
      root@localhost    #邮件接收者
   }
   notification_email_from lvs@localhost  #邮件发送者
   smtp_server 127.0.0.1     #邮件服务器地址，如未安装，使用本地
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

#IP漂移协议
vrrp_instance VI_1 {
    state MASTER   #指定A节点为主节点 备分机上设置为BACKUP即可
    interface eth0  #绑定IP漂移的网络接口，在该接口上绑定VIP
    virtual_router_id 51   #VRRP组名，两个节点的设置必须一样
    priority 100  
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.232.206/24 dev eth0 label eth0:1   #绑定VIP
    }
}

#只接收80端口过来的请求
virtual_server 192.168.232.206 80 {
    delay_loop 6
    lb_algo wlc   #轮循
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP

    #RS服务器1
    real_server 192.168.232.200 80 {
        weight 1
    　　 #健康检查
        HTTP_GET {
            url {
              path /
              status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    #RS服务器2
    real_server 192.168.232.204 80 {
        weight 1
    　　 #健康检查
        HTTP_GET {
            url {
              path /
              status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
} 

　　　　备机：Lvs+keepalived（BACKUP）

global_defs {
   #指定keepalived在发生切换时需要发送email到的对象
   notification_email { 
      root@localhost    #邮件接收者
   }
   notification_email_from lvs@localhost  #邮件发送者
   smtp_server 127.0.0.1     #邮件服务器地址，如未安装，使用本地
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

#IP漂移协议
vrrp_instance VI_1 {
    state BACKUP  #指定A节点为主节点 备分机上设置为BACKUP即可
    interface eth0  #绑定IP漂移的网络接口，在该接口上绑定VIP
    virtual_router_id 51   #VRRP组名，两个节点的设置必须一样
    priority 99  
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.232.206/24 dev eth0 label eth0:1   #绑定VIP
    }
}

#只接收80端口过来的请求
virtual_server 192.168.232.206 80 {
    delay_loop 6
    lb_algo wlc   #轮循
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP

    #RS服务器1
    real_server 192.168.232.200 80 {
        weight 1
    　　 #健康检查
        HTTP_GET {
            url {
              path /
              status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    #RS服务器2
    real_server 192.168.232.204 80 {
        weight 1
    　　 #健康检查
        HTTP_GET {
            url {
              path /
              status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
} 

　　3. 启动两台Lvs转发服务器的Keepalived服务：service keepalived start

　　4.通过ifconfig命令查看主从Lvs转发服务器的网络接口：

　　　　

　　　　

　　5.查看地址和端口号：ipvsadm -Ln

　　　　

　　6.使用浏览器进行访问：http://192.168.232.206:80/

　　　　

　　　7.主机挂掉：init 6