keepalived檢測腳本及注意事項

keepalived檢測腳本的作用及注意事項：

1. 默認每隔3秒鍾執行一次檢測腳本，檢查nginx服務是否啟動，如果沒啟動就把nginx服務啟動起來，如果啟動不成功，就把keepalived服務down掉，讓漂浮到備keepalived上

2. 檢測腳本
   #!/bin/bash
   run=`ps -C nginx --no-header | wc -l`
   if [ $run -eq 0 ]
   then
   /usr/local/nginx/sbin/nginx -s stop
   /usr/local/nginx/sbin/nginx
   sleep 3
   if [ `ps -C nginx --no-header | wc -l` ]
   then
   killall keepalived
   fi
   fi

3. 檢測腳本一定要寫在vrrp_instance的前面也就是上面，而且花括號一定要有空格，追蹤trace_script要定在vip的后面，多少人栽在了這上面好多小時

4. vrrp_script check_ng {
   script " /etc/keepalived/check_nginx.sh "
   interval 2
   }
   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 {
   192.168.76.25/24
   }
   track_script {
   check_ng
   }
   }