Nagios check memory

### Memory Check

1. 모니터링 대상 서버 check memory 설정

cd /usr/local/nagios/libexec/
vi check_mem

# 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 퍼센트) Free Memory"
exit 2
fi

if [[ "$percent" -le $warning ]]
then
        echo "WARNING - $free MB ($percent 퍼센트) Free Memory"
        exit 1
fi

if [[ "$percent" -gt $warning ]]
then
        echo "OK - $free MB ($percent 퍼센트) Free Memory"
        exit 0
fi

chmod +x ./check_mem
chown nagios:nagios ./check_mem

### nrpe service 등록
vi /usr/local/nagios/etc/nrpe.cfg
command[check_mem]=/usr/local/nagios/libexec/check_mem -w 20 -c 10

### nrpe Service 재시작
systemctl restart nrpe

 

2. Nagios Server Service 등록

vi /usr/local/nagios/etc/object/service.cfg

define service {
        use                     generic-service
        host_name               test-server
        service_description     Memory Usage
        check_command           check_nrpe!check_mem
        }
        
### Nagios Server Restart
systemctl restart nagios