check_linux_ntp_time

#!/bin/bash

Usage()
{
  echo "Usage: $0 -H host -w warning -c critical (in seconds)"
}

while getopts ":H:w:c:" opt
do
  case ${opt} in
    H )
      host=${OPTARG}
      ;;
    w )
      warning=${OPTARG}
      ;;
    c )
      critical=${OPTARG}
      ;;
    * )
      Usage
      exit 2
      ;;
  esac
done
shift $((OPTIND-1))

if [ -z "${host}" ] || [ -z "${warning}" ] || [ -z "${critical}" ]
then
  Usage
  exit 2
fi

if (( $(echo "$warning > $critical" | bc -l) ))
then
	echo "Warning threshold cannot be equal or bigger than critical"
	exit
fi

ntp_config=`ssh nagios@$host "grep -w ^server /etc/ntp.conf 2> /dev/null"`
if [[ -z $ntp_config ]]
then
	ntp_config=`ssh nagios@$host "grep -w ^server /etc/chrony.conf 2>/dev/null"`
	if [[ -z $ntp_config ]]
	then
		echo "SSH/ntp.conf/chrony.conf error"
		exit 3
	fi
fi

ntp_servers=`echo $ntp_config | sed -r 's/\b(iburst|server)\b//g'`

for server in $ntp_servers
do
  remote=`ssh nagios@$host "/usr/sbin/ntpdate -q $server"`
  if [ $? -eq 0 ]
  then
  	diff=`echo $remote| awk '{print $6}' | cut -d , -f1`
  	ntp_server=$server
    break
  fi
done

if [ -z "$remote" ]
then
   echo "Check failed. Issue with ntpdate"
   exit 3
fi

diff=${diff/-/}

if [[ "$diff" > "$critical" ]]
then
	echo "CRITICAL: Offset is $diff seconds, to: $ntp_server | Status=2"
	exit 2
fi

if [[ "$diff" > "$warning"  ]]
then
	echo "WARNING: Offset is $diff seconds, to: $ntp_server | Status=1"
	exit 1
fi

echo "OK: In sync with: $ntp_server | Status=0"
exit 0