Nagios Plugins

check_mem

#!/bin/bash

# An updated memory plugin to use MemAvailable rather than MemFree

# TODO: Error check for kernel version (check MemAvailable is available in /proc/meminfo)
# TODO: Add swap checks
# TODO: Improve rounding

command -v bc > /dev/null 2>&1 || {
    echo "UNKNOWN - Missing Command: bc"
    exit 3
}

USAGE="`basename $0` [-w|--warning] <percent used> [-c|--critical] <percent used>"

if [[ $# -lt 4 ]]; then
    echo -e "UNKNOWN - Incorrect Syntax: `basename $0` $*\nUsage: $USAGE"
    exit 3
fi

while [[ $# -gt 0 ]]; do
    case "$1" in
        -w|--warning)
            shift
            WARN=$1
        ;;
        -c|--critical)
            shift
            CRIT=$1
        ;;
    esac
    shift
done

if [[ $CRIT -le $WARN ]]; then
    THRESHOLD_USAGE="Critical threshold must be greater than warning threshold: `basename $0` $*"
    echo -e "UNKNOWN - $THRESHOLD_USAGE"
    exit 3
fi

TOTAL=`grep -o '^MemTotal:.*kB$' /proc/meminfo | gawk '{print "scale=4; "$2"/1024"}' | bc`
AVAILABLE=`grep -o '^MemAvailable:.*kB$' /proc/meminfo | gawk '{print "scale=4; "$2"/1024"}' | bc`
USED=`echo "scale=4; $TOTAL-$AVAILABLE" | bc`
USED_WARN=`echo "scale=0; $TOTAL*$WARN/100" | bc`
USED_CRIT=`echo "scale=0; $TOTAL*$CRIT/100" | bc`
PERCENT=`echo "scale=2; 100-100*$AVAILABLE/$TOTAL" | bc`

if [[ "`echo "$PERCENT >= $CRIT" | bc`" -eq 1 ]]; then
    echo "CRITICAL - Memory $PERCENT% used - ${AVAILABLE::-3}MB memory left | 'Memory Used'=${USED}MB;$USED_WARN;$USED_CRIT;0;${TOTAL::-5}"
    exit 2
elif [[ "`echo "$PERCENT >= $WARN" | bc`" -eq 1 ]]; then
    echo "WARNING - Memory $PERCENT% used - ${AVAILABLE::-3}MB memory left | 'Memory Used'=${USED}MB;$USED_WARN;$USED_CRIT;0;${TOTAL::-5}"
    exit 1
elif [[ "`echo "$PERCENT < $WARN" | bc`" -eq 1 ]]; then
    echo "OK - Memory $PERCENT% used - ${AVAILABLE::-3}MB memory left | 'Memory Used'=${USED}MB;$USED_WARN;$USED_CRIT;0;${TOTAL::-5}"
    exit 0
fi