然后介绍nrpe的check脚本。脚本不管怎么写都行，对于nagios服务器端来说，它除了接受脚本的输出结果外，只认脚本运行的退出值（测试时可以运行后用echo $?看），包括OK的exit 0、WARNING的exit 1、CRITICAL的exit 2、未知的exit 3。
#!/bin/bash
#Written by Gemmy.Rao
#Version 0.2
#CHANGES
#Add -p option for checking other service's port
#Init
PORT=80
WARNING=5000
CRITICAL=20000
#get options
while getopts "w:c:p:hs" OPT;do
case $OPT in
w)
WARNING=${OPTARG}
;;
c)
CRITICAL=${OPTARG}
;;
p)
PORT=${OPTARG}
#转换各端口的十进制成十六进制
PORT_16=`echo ${PORT}|awk -F, '{for(i=1;i<=NF;i++)printf "|%.4X",$i}'|sed 's/|//'`
;;
h)
echo "Usage: $0 -w 500 -c 2000 -p 80,8081 -s"
exit 0
;;
s)
SILENT=1
;;
*)
echo "Usage: $0 -w 500 -c 2000 -p 80,8081"
exit 0
;;
esac
done
#经过time测试，取值速度netstat > awk '//{a++}END{print a}' > cat|grep|wc > cat|awk|wc，在2w连接下，netstat要20s，最快的方式不到5s（一般nagios到10s就该直接报timeout了）
PORT_CONN=`cat /proc/net/tcp*|awk '$2~/:('$PORT_16')$/'|wc -l`
if [[ "$SILENT" == 1 ]];then
[[ -d /usr/local/nagios ]] || mkdir -p /usr/local/nagios
echo "Silent log write OK | Port ${PORT}=${PORT_CONN};${WARNING};${CRITICAL};0;0"
echo -en "`date`t$PORT_CONNn" >> /usr/local/nagios/conn.log
exit 0
elif [[ "$PORT_CONN" -lt "$WARNING" ]];then
echo "Port $PORT connection OK for $PORT_CONN. | Port ${PORT}=${PORT_CONN};${WARNING};${CRITICAL};0;0"
exit 0
elif [[ "$PORT_CONN" -gt "$CRITICAL" ]];then
echo "Port $PORT connection critical for $PORT_CONN!! | Port ${PORT}=${PORT_CONN};${WARNING};${CRITICAL};0;0"
exit 2
else
echo "Port $PORT connection warning for $PORT_CONN! | Port ${PORT}=${PORT_CONN};${WARNING};${CRITICAL};0;0"
exit 1
fi
