Nagios time check using SNMP
When you would like to retrieve the remotely configured time using SNMP and compare it to see how accurate the time is, here is a script to help you out.
This setup does not specifically require NTP to be running on the hosts that are checked, it just requires that the time is correct. Virtual machines for example are advised to have the appropriate "tools" installed to synchronize time. NTP is not desirable for virtual machines.
(Parts of the script are borrowed from http://spielwiese.la-evento.com/xelasblog/archives/27-SNMP-hrSystemDate.0-Datumsformat-anpassen.html)
This is the graph that is created:
The script:
#!/bin/sh
# Nagios plugin to report time difference as received via SNMP compared to the local time.
# Make sure the machine this script runs on (poller/nagios host) is using NTP.
usage() {
# This function is called when a user enters impossible values.
echo "Usage: $0 -H HOSTADDRESS [-C COMMUNITY] [-w WARNING] [-c CRITICAL] [-v VERSION]"
echo
echo " -H HOSTADDRESS"
echo " The host to check, either IP address or a resolvable hostname."
echo " -C COMMUNITY"
echo " The SNMP community to use, defaults to public."
echo " -v VERSION"
echo " The SNMTP version to use, defaults to 2c."
echo " -w WARNING"
echo " The amount of seconds from where warnings start. Defaults to 60."
echo " -c CRITICAL"
echo " The amount of seconds from where criticals start. Defaults to 120."
exit 3
}
readargs() {
# This function reads what options and arguments were given on the
# command line.
while [ "$#" -gt 0 ] ; do
case "$1" in
-H)
if [ "$2" ] ; then
host="$2"
shift ; shift
else
echo "Missing a value for $1."
echo
shift
usage
fi
;;
-C)
if [ "$2" ] ; then
community="$2"
shift ; shift
else
echo "Missing a value for $1."
echo
shift
usage
fi
;;
-w)
if [ "$2" ] ; then
warning="$2"
shift ; shift
else
echo "Missing a value for $1."
echo
shift
usage
fi
;;
-c)
if [ "$2" ] ; then
critical="$2"
shift ; shift
else
echo "Missing a value for $1."
echo
shift
usage
fi
;;
-v)
if [ "$2" ] ; then
version="$2"
shift ; shift
else
echo "Missing a value for $1."
echo
shift
usage
fi
;;
*)
echo "Unknown option $1."
echo
shift
usage
;;
esac
done
}
checkvariables() {
# This function checks if all collected input is correct.
if [ ! "$host" ] ; then
echo "Please specify a hostname or IP address."
echo
usage
fi
if [ ! "$community" ] ; then
# The public community is used when a user did not enter a community.
community="public"
fi
if [ ! "$version" ] ; then
# Version 2c is used when a user did not enter a version.
version="2c"
fi
if [ ! "$critical" ] ; then
critical="120"
fi
if [ ! "$warning" ] ; then
warning="60"
fi
}
getandprintresults() {
# This converts the date retreived from snmp to a unix time stamp.
rdatestring=$( snmpget -v $version -c $community $host HOST-RESOURCES-MIB::hrSystemDate.0 | gawk '{print $NF}' )
if [ ! "$rdatestring" ] ; then
echo "Time difference could not be calculated; no time received."
exit 3
fi
rdate=$( echo $rdatestring | gawk -F',' '{print $1}' )
rtime=$( echo $rdatestring | gawk -F',' '{print $2}' | gawk -F'.' '{print $1}' )
cldate=$( echo $rdate | gawk -F'-' '{printf("%4i",$1)}; {printf("%02i",$2)}; {printf("%02i",$3)};' )
cltime=$( echo $rtime | gawk -F':' '{printf("%02i",$1)}; {printf("%02i",$2)}; {printf(" %02i",$3)};' )
rdate_s=$( date -d "$cldate $cltime sec" +%s )
ldate_s=$(date +'%s')
# If the calculated difference is negative, make it positive again for comparison.
difference=$(($rdate_s - $ldate_s))
if [ "$difference" -lt 0 ] ; then
positivedifference=$(($difference*-1))
else
positivedifference=$difference
fi
if [ "$positivedifference" -gt "$critical" ] ; then
echo "Time difference is more than $critical seconds: $difference|diff=$difference"
exit 2
fi
if [ "$positivedifference" -gt "$warning" ] ; then
echo "Time difference is more than $warning seconds: $difference|diff=$difference"
exit 1
fi
echo "Time difference is less than $warning seconds: $difference|diff=$difference"
exit 0
}
# The calls to the different functions.
readargs "$@"
checkvariables
getandprintresultsTo implement it in Nagios, add these sniplets to nagios.cfg. (or any other applicable nagios file.)
The service for a group.
define service{
hostgroup_name Servertype_Linux
service_description time
_SERVICE_ID 1856
use SNMP-time
}The service template.
define service{
name SNMP-time
service_description time
use generic-service
check_command check_snmp_time!$_HOSTSNMPCOMMUNITY$!120!60
max_check_attempts 30
normal_check_interval 5
retry_check_interval 1
notification_interval 0
register 0
}The command.
define command{
command_name check_snmp_time
command_line $USER1$/check_snmp_time -H $HOSTADDRESS$ -C $ARG1$ -c $ARG2$ -w $ARG3$
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Comments
Thanks, this is great! Why is
Thanks, this is great!
Why is it not on the Nagios exchange site? http://exchange.nagios.org/directory/Plugins/System-Metrics/Time
Great script doing just what
Great script doing just what I was looking for
Thanks!
Thanks! This is very useful
Thanks! This is very useful to me.
Exactly what i needed. Works
Exactly what i needed. Works great.
Thanks from Brittany, France !
Julien,