keepalived中vrrp_script,track_script,notify的使用方法

keepalived中vrrp_script,track_script,notify的使用方法
轉自：https://blog.51cto.com/liuzhengwei521/1929589

可以在keepalived.conf文件中定義的腳本，用以實現某個檢測功能；
例：檢測/etc/keepalived目錄下down文件是否存在，如果存在則優先級減20，如果不存在表示正常
vrrp_script chk {
  script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
  interval 1
  weight -20
注：這個腳本的作用是用於維護MASTER,使MASTER手動下線
如何調用上面定義的腳本呢？
  在vrrp實例中(vrrp_instance VI_1)加上track_script用於追蹤腳本
  track_script {
    chk
  }
notify的用法：
  notify_master:當當前節點成為master時，通知腳本執行任務(一般用於啟動某服務，比如nginx,haproxy等)
  notify_backup:當當前節點成為backup時，通知腳本執行任務(一般用於關閉某服務，比如nginx,haproxy等)
  notify_fault：當當前節點出現故障，執行的任務; 
  例：當成為master時啟動haproxy,當成為backup時關閉haproxy
  notify_master "/etc/keepalived/start_haproxy.sh start"
  notify_backup "/etc/keepalived/start_haproxy.sh stop"
一個完整的實例：
  MASTER:初始priority為100
  BACKUP:初始priority為90
  模擬MASTER產生故障：
  當檢測到/etc/keepalived目錄下有down文件時，priority減少20，變為80；低於BACKUP的priority；
  此時MASTER變成BACKUP，同時執行notify_backup的腳本文件（關閉haproxy）；
  同時BACKUP變成MASTER，同時執行notify_master的腳本文件（啟動haproxy）；
  模擬MASTER故障恢復：
  當刪除/etc/keepalived目錄下的down文件時，原MASTER的優先級又變為100，高於原BACKUP的priority;
  此時原MASTER由BACKUP又搶占成了MASTER,同時執行notify_master的腳本文件（啟動haproxy）；
  同時原BACKUP由MASTER又變了BACKUP,同時執行notify_backup的腳本文件（關閉haproxy）；
MASTER的配置：
global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script chk {
   script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
   interval 1
   weight -20
}
vrrp_instance VI_1 {
    state MASTER
    interface eth1
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.0.22.245
    }
    track_script {
      chk
    }
    notify_master "/etc/keepalived/start_haproxy.sh start"
    notify_backup "/etc/keepalived/start_haproxy.sh stop"
BACKUP的配置：
global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
 
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
       10.0.22.245
    }
    notify_master "/etc/keepalived/start_haproxy.sh start"
    notify_backup "/etc/keepalived/start_haproxy.sh stop"
 
}
start_haproxy.sh的腳本內容：
#!/bin/bash
case "$1" in
  start)
    /etc/init.d/haproxy start
  ;;
  stop)
    /etc/init.d/haproxy stop
  ;;
  restart)
    /etc/init.d/haproxy stop
    /etc/init.d/haproxy start
  *)
    echo "Usage:$0 start|stop|restart"
  ;;
esac
keepalived檢測nginx,當nginx服務不正常時自動降級，當nginx恢復時自動升級：
check_nginx.sh腳本
#!/bin/bash
nmap localhost -p 80 | grep "80/tcp open"
if [ $? -ne 0 ];then
        exit 10
fi
notify.sh腳本：
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" [e-mail]
}
case "$1" in
  master)
        nmap localhost -p 80 | grep "80/tcp open"
        if [ $? -ne 0 ];then
                /etc/init.d/nginx start
        fi
        sendmail
  ;;
  backup)
        nginx_psr=`ps -C nginx --no-header | wc -l`
        if [ $nginx_psr -ne 0 ];then
                /etc/init.d/nginx stop
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac
MASTER配置
! Configuration File for keepalived

global_defs {
    notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id https
}
vrrp_script chk_nginx {
    script "/etc/keepalived/check_nginx.sh"
    interval 1
    weight -20
}
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 54
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
    172.16.8.19/25
    }
    track_script {
    chk_nginx
    }
    notify_master "/etc/keepalived/notify.sh master 172.16.8.19"
    notify_backup "/etc/keepalived/notify.sh backup 172.16.8.19"
}
BACKUP配置：
backup無需檢測nginx是否正常，默認nginx是未啟動的，當升級為MASTER時啟動nginx，當降級為BACKUP時關閉
! Configuration File for keepalived

global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id https
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 54
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
    172.16.8.19/25
    }
    notify_master "/etc/keepalived/notify.sh master 172.16.8.19"
    notify_backup "/etc/keepalived/notify.sh backup 172.16.8.19"
}