ntp_offset.sh

#!/bin/bash

# ntp_offset.sh
# Rackspace Cloud Monitoring Plugin to verify the time offset from ntp
#
# Copyright (c) 2013, Jordan Evans <jordan.evans@rackspace.com>
# Copyright (c) 2014, Simon Vetter <simon.vetter@runbox.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
#
# This plugin expects to find ntpq and awk in the environment
# it reports the average ntp offset from ntpq in milliseconds.
#
# Example alarm code:
# :set consecutiveCount=3
# if (metric['ntp_offset'] > 10000 || metric['ntp_offset'] < -10000) {
#   return new AlarmStatus(CRITICAL, 'ntp offset is too high.');
# }
# return new AlarmStatus(OK, 'ntp offset is fine.');
#
# if (metric['active_sources'] < 2) {
#   return new AlarmStatus(WARNING, 'ntpd is only using #{active_sources} sources');
# }
# return new AlarmStatus(OK, 'ntpd has #{active_sources} active sources');
#

NTPQ_BIN=$(which ntpq)
AWK_BIN=$(which awk)

if [[ -x $NTPQ_BIN ]] && [[ -x $AWK_BIN ]]
  then
    # only select line starting with * (system peer), + (candidate), # (selected), and o (pps sys peer)
    OUTPUT=$($NTPQ_BIN -pn | $AWK_BIN '{ if ($1 ~ "^[\\*\\+#o].*" && $9 ~ /[0-9]/) print $9};' | cut -f 1 -d '.')

    for x in ${OUTPUT}
    do
      sum=$(($sum + $x))
      count=$(($count + 1))
    done

    if [[ ${count} -gt 0 ]]; then
      avg=$(($sum / $count))
      echo "status ok got ntp stats"
      echo "metric ntp_offset int32 ${avg} milliseconds"
      echo "metric active_sources uint32 ${count} sources"
      exit 0
    else
      echo "status err could not compute ntp offset: no reachable or active source"
    fi
  else
    echo "status err could not compute ntp offset: ntpq and/or awk could not be found"
fi

exit 1