keepalived中vrrp_script,track_script,notify的使用方法

可以在keepalived.conf文件中定义的脚本，用以实现某个检测功能；

例：检测/etc/keepalived目录下down文件是否存在，如果存在则优先级减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：这个脚本的作用是用于维护MASTER,使MASTER手动下线

如何调用上面定义的脚本呢？

  在vrrp实例中(vrrp_instance VI_1)加上track_script用于追踪脚本

  track_script {

    chk

  }

notify的用法：

  notify_master:当当前节点成为master时，通知脚本执行任务(一般用于启动某服务，比如nginx,haproxy等)

  notify_backup:当当前节点成为backup时，通知脚本执行任务(一般用于关闭某服务，比如nginx,haproxy等)

  notify_fault：当当前节点出现故障，执行的任务; 

  例：当成为master时启动haproxy,当成为backup时关闭haproxy

  notify_master "/etc/keepalived/start_haproxy.sh start"

  notify_backup "/etc/keepalived/start_haproxy.sh stop"

一个完整的实例：

  MASTER:初始priority为100

  BACKUP:初始priority为90

  模拟MASTER产生故障：

  当检测到/etc/keepalived目录下有down文件时，priority减少20，变为80；低于BACKUP的priority；

  此时MASTER变成BACKUP，同时执行notify_backup的脚本文件（关闭haproxy）；

  同时BACKUP变成MASTER，同时执行notify_master的脚本文件（启动haproxy）；

  模拟MASTER故障恢复：

  当删除/etc/keepalived目录下的down文件时，原MASTER的优先级又变为100，高于原BACKUP的priority;

  此时原MASTER由BACKUP又抢占成了MASTER,同时执行notify_master的脚本文件（启动haproxy）；

  同时原BACKUP由MASTER又变了BACKUP,同时执行notify_backup的脚本文件（关闭haproxy）；

MASTER的配置：

global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   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 {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   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的脚本内容：

#!/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检测nginx,当nginx服务不正常时自动降级，当nginx恢复时自动升级：

check_nginx.sh脚本

#!/bin/bash
nmap localhost -p 80 | grep "80/tcp open"
if [ $? -ne 0 ];then
        exit 10
fi

notify.sh脚本：

#!/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" [email protected]
}
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 {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   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无需检测nginx是否正常，默认nginx是未启动的，当升级为MASTER时启动nginx，当降级为BACKUP时关闭

! Configuration File for keepalived
global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   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"
}
出处：http://blog.51cto.com/liuzhengwei521/1929589