check_memory.sh: add plugin to check memory usage on Linux

check_memory.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+# Origninal from http://blog.vergiss-blackjack.de/wp-uploads/2010/04/check_memory.txt
+# Modified by Jon Schipp
+
+# Nagios plugin to check memory consumption
+# Excludes Swap and Caches so only the real memory consumption is considered
+
+# Nagios Exit Codes
+OK=0
+WARNING=1
+CRITICAL=2
+UNKNOWN=3
+
+# set default values for the thresholds
+WARN=90
+CRIT=95
+
+usage()
+{
+cat <<EOF
+
+Check memory consumption excluding swap and cache to determine real usage.
+
+     Options:
+        -c         Critical threshold as percentage (0-100) (def: 95)
+        -w         Warning threshold as percentage (0-100) (def: 90)
+
+Usage: $0 -w 90 -c 95
+EOF
+}
+
+while getopts "c:w:h" ARG;
+do
+        case $ARG in
+                w) WARN=$OPTARG
+                   ;;
+                c) CRIT=$OPTARG
+                   ;;
+                h) usage
+                   exit
+                   ;;
+        esac
+done
+
+MEM_TOTAL=`free | fgrep "Mem:" | awk '{ print $2 }'`;
+MEM_USED=`free | fgrep "/+ buffers/cache" | awk '{ print $3 }'`;
+
+PERCENTAGE=$(($MEM_USED*100/$MEM_TOTAL))
+RESULT=$(echo "${PERCENTAGE}% ($((($MEM_USED)/1024)) of $((MEM_TOTAL/1024)) MB) used")
+
+if [ $PERCENTAGE -gt $CRIT ]; then
+        echo "CRITICAL: $RESULT"
+        exit $CRITICAL;
+elif [ $PERCENTAGE -gt $WARN ]; then
+        echo "WARNING: $RESULT"
+        exit $WARNING;
+else
+        echo "OK: $RESULT"
+        exit $OK;
+fi
+