keepalived中vrrp_script,track_script,notify的使用方法

车皮

　　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 {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   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 {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   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" zhengwei.liu@staples.cn
}
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 {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   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 {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   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"
}