#!/usr/bin/bash
## monitor CPU iowait.
## Get avarage of recent 5 seconds. If iowait% avarage in several seconds too high,
## then report warning or critical.
## example "sar" command output is as follows.
## 15:19:58        CPU     %user     %nice   %system   %iowait    %steal     %idle
## 15:19:59        all      0.00      0.00      0.00      0.00      0.00    100.00
## 15:19:59          0      0.00      0.00      0.00      0.00      0.00    100.00

usage_exit(){
	echo "usage: $0 -w <Warning_percentage> -c <Critical_percentage>"
	echo "ex: $0 -w 70 -c 99"
	exit 1
}

while getopts c:w:h OPT
do
	case $OPT in
		c) CRIT=$OPTARG
			;;
		w) WARN=$OPTARG
			;;
		h) usage_exit
			;;
		*) usage_exit
			;;
	esac
done

if [[ -z $CRIT ]];then
	usage_exit
fi

IOWAIT=$( sar -P ALL 5 1 | awk '{print $6}' | sort -nr | head -1 )

if [[ -z $IOWAIT ]]; then
        echo "UNKOWN - Error to get iowait info from sar command"
        exit 3
fi

MSG=" maximum iowait is ${IOWAIT}% | iowait=${IOWAIT};;;;"

if [[ $(echo "$IOWAIT > $CRIT" | bc) == 1 ]]; then
        echo "CRITICAL - $MSG"
        exit 2
elif [[ $(echo "$IOWAIT > $WARN" | bc) == 1 ]]; then
        echo "WARNING - $MSG"
        exit 1
fi
echo "OK - $MSG"
exit 0