nagios check_memory 插件开发

#!/bin/bash
#describe:nagios  check_memory
#return:0:OK|1:waring|2:critical|3:unknown
#Usage:-w(waring) -c(cirtical) -u(KB|MB|GB|TB) -h(--help) -v(--version)

WARING=
CIRTICAL=

UNIT=
VERSION='1.0.1'

declare -A UNIT_MAP
UNIT_MAP=([KB]=0 [MB]=1 [GB]=2 [TB]=3)
UNIT_MIX=1024

help=no
version=no

for option
do
  case "$option" in
     -*=*) value=`echo $option|sed 's/[-a-zA-Z0-9]*=//'` ;;
     *) value="" ;;
  esac

  case "$option" in
    -h) help=yes ;;
    --help) help=yes ;;
    -v) version=yes ;;
    -w=*) WARING="$value" ;;
    -c=*) CIRTICAL="$value" ;;
    -u=*) UNIT="$value" ;;
    *)
    echo "$0: error: invalid option \"$option\""
    exit 3
    ;;
  esac
done

if [ $help = yes ];then
   cat << END
       check_memory [option] [value]
            nagios check memory
            Support the percentage comparison, does not support equivalence comparison

       --help              print this message
       -h                  print this message
       -v                  print this version

       -w                  set waring value
       -c                  set cirtical value
       -u                  set the display unit
END

   exit 0
fi


if [ $version = yes ];then
   echo "Copyright: check_memory/$VERSION"
   exit 0
fi

WARING=${WARING:-'20'}
CIRTICAL=${CIRTICAL:-'10'}
UNIT=${UNIT:-'MB'}

if [ -z ${UNIT_MAP[$UNIT]} ];then
   UNIT='MB'
fi

UNIT_DIV=$(($UNIT_MIX**${UNIT_MAP[$UNIT]}))

total=$(free |awk '/Mem/{print $2}')
free_avg=$(free -s1 -c5|grep "+"|awk 'BEGIN{free=0}{free+=$4}END{printf("%.0f",free/5)}')
precent=`echo "scale=0;"$free_avg \* 100 / $total |bc`

free_avg=`echo "scale=2;"$free_avg / $UNIT_DIV |bc`
total=`echo "scale=2;"$total / $UNIT_DIV |bc`

if test $precent -le $CIRTICAL;then
   echo "cirtical,total:$total$UNIT,free space:$free_avg$UNIT,precent:$precent%"
   exit 2
fi

if test $precent -le $WARING;then
   echo "waring,total:$total$UNIT,free space:$free_avg$UNIT,precent:$precent%"
   exit 1
fi

echo "free ok,total:$total$UNIT,free space:$free_avg$UNIT,precent:$precent%"
exit 0