这个是脚本,保存到 /usr/local/nagios/libexce/check_mem.sh

# Script to check real memory usage
# L.Gill 02/05/06 - V.1.0
# ------------------------------------------
# ########  Script Modifications  ##########
# ------------------------------------------
# Who         When           What
# ---    ----      ----
# LGill         17/05/06  "$percent" lt 1% fix - sed edits dc result beggining with "."
#
#
#!/bin/bash
USAGE="`basename $0` [-w|--warning]<percent free> [-c|--critical]<percent free>"
THRESHOLD_USAGE="WARNING threshold must be greater than CRITICAL: `basename $0` $*"
calc=/tmp/memcalc
percent_free=/tmp/mempercent
critical=""
warning=""
STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3
# print usage
if [[ $# -lt 4 ]]
then
        echo ""
        echo "Wrong Syntax: `basename $0` $*"
        echo ""
        echo "Usage: $USAGE"
        echo ""
        exit 0
fi
# read input
while [[ $# -gt 0 ]]
  do
        case "$1" in
               -w|--warning)
               shift
               warning=$1
        ;;
               -c|--critical)
               shift
               critical=$1
        ;;
        esac
        shift
  done

# verify input
if [[ $warning -eq $critical || $warning -lt $critical ]]
then
        echo ""
        echo "$THRESHOLD_USAGE"
        echo ""
        echo "Usage: $USAGE"
        echo ""
        exit 0
fi
# Total memory available
total=`free -m | head -2 |tail -1 |gawk '{print $2}'`
# Total memory used
used=`free -m | head -2 |tail -1 |gawk '{print $3}'`
# Calc total minus used
free=`free -m | head -2 |tail -1 |gawk '{print $2-$3}'`
# normal values
#echo "$total"MB total
#echo "$used"MB used
#echo "$free"MB free
# make it into % percent free = ((free mem / total mem) * 100)
echo "5" > $calc # decimal accuracy
echo "k" >> $calc # commit
echo "100" >> $calc # multiply
echo "$free" >> $calc # division integer
echo "$total" >> $calc # division integer
echo "/" >> $calc # division sign
echo "*" >> $calc # multiplication sign
echo "p" >> $calc # print
percent=`/usr/bin/dc $calc|/bin/sed 's/^\./0./'|/usr/bin/tr "." " "|/usr/bin/gawk {'print $1'}`
#percent1=`/usr/bin/dc $calc`
#echo "$percent1"
if [[ "$percent" -le  $critical ]]
        then
                echo "CRITICAL - $free MB ($percent%) Free Memory"
                exit 2
fi
if [[ "$percent" -le  $warning ]]
        then
                echo "WARNING - $free MB ($percent%) Free Memory"
                exit 1
fi
if [[ "$percent" -gt  $warning ]]
        then
                echo "OK - $free MB ($percent%) Free Memory"
                exit 0
fi

----------------------------------------------------------------------------------------------------------

添加到command.cfg
2. vim /usr/local/nagios/etc/object/command.cfg

# 'check_mem' command definition
define command{
        command_name    check_mem
        command_line    $USER1$/check_mem.sh -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$ -p $ARG1$
        }


3. define service{
       use                             generic-service    
        host_name                       10.1.1.6
        service_description             check_mem
        is_volatile                     0
        check_period                    24x7
        max_check_attempts              4
        normal_check_interval           5
        retry_check_interval            1
        contact_groups                  doggroup
        notification_options            w,u,c,r
        notification_interval           960
        notification_period             24x7
        check_command                   check_mem!20!5
        }
4.以上可以监控本地的内存。