nagios plugin for hbase to check how many regions a region server is serving and throw critical if regions > 90

check_hbase_onlineregions.sh

#!/usr/bin/env bash

#Author: Ashrith

#Arrays to store hosts and their regionsOnLine respectively
declare -a HOSTS_ARRAY
declare -a REGIONS_ARRAY
message="" 
EXIT_STATUS=0

OUTPUT=`echo "status 'simple'" | hbase shell`
if [ ${PIPESTATUS[1]} -ne 0 ]; then
  message="[Unknown] Hbase shell command not found in path" 
  exit 3
fi

#Find data between patterns 'live servers' and 'dead servers'
#Bug: New line characters are stripped away from output if variable is not quoted properly
start=`echo "$OUTPUT" | grep -n 'live servers' | head -n1 | cut -d: -f1`
stop=`echo "$OUTPUT" | tail -n +$start | grep -n 'dead servers' | cut -d: -f1`
stop=$(($stop + $start - 1))

#Trim the output from captured output
TRIMMED_OUTPUT=`echo "$OUTPUT" | sed "$start,$stop!d" | sed -e '1d' -e '$d'`

#Process data
#set IFS to read line by line
nodes_count=0
regions_count=0
while IFS= read -r line
do
  echo $line | grep -q "numberOfOnlineRegions"
	[ $? -eq 0 ] && {
		#echo "processing regions count"
		regions_online=`echo $line | awk '{print $2}' | cut -d= -f2`
		#echo ${regions_online%?}
		REGIONS_ARRAY[$regions_count]=${regions_online%?}
		((++regions_count))
	} || {
		#echo "processing nodes"
		node=`echo $line | cut -d: -f1`
		#echo $node
		HOSTS_ARRAY[$nodes_count]=$node
		((++nodes_count))
	}
done <<< "$TRIMMED_OUTPUT" #if while is used with pipe, counters will be out of scope

#Build a output string
for ((i=0; i<${nodes_count}; i++)); do
	message="${message} Node: ${HOSTS_ARRAY[$i]} \t RegionsOnLine: ${REGIONS_ARRAY[$i]} \n"
	if [ ${REGIONS_ARRAY[$i]} -ge 90 ]; then
		message="$message [WARNING] Node: ${HOSTS_ARRAY[$i]} has regions count > 90"
    EXIT_STATUS=2
	fi	
done
echo -e $message
exit $EXIT_STATUS