Is it possible to monitor NTP through SNMP in Linux

[neelakandan]

Is it possible to monitor the NTP drift value ( I mean measuring the time difference between the NTP server and the server that I am trying to monitor) using SNMP.

Appreciate any help in this regard.

[atreyu]

All this is assuming you have snmp daemon configured and running on your Linux box.

You can get current system date/time with:

snmpwalk -Cc -On -v2c -c public localhost .1.3.6.1.4.1.2021.100.4.0

provided that snmpd is set up and configured properly for this on the Linux box, but you probably want something more granular.

There may be a way to directly access NTP info via an OID, but I don't know it.

Fortunately, it is possible to monitor anything in SNMP via the exec directive or maybe pass (PASS-THROUGH-CONTROL), never used the latter. For example, you can put this in your snmpd.conf on the Linux box:

# run external script to return drift info
exec 1.3.6.1.4.1.2021.8.1.101 get-drift /tmp/get-drift.sh

Then create /tmp/get-drift.sh and put in it the code to determine drift. I don't know how to do that, but I gather it would be some sort of ntpdate command. Here's something to start with that would work on a RH/Fedora box, e.g.:

#!/bin/bash

# location of ntp config file
ntpConf=/etc/ntp.conf

# make sure it exists
! [ -f $ntpConf ] && echo "$ntpConf: No such file" && exit 1

# get an ntp server from the config file
server=$(awk '/^server/{print $2}' $ntpConf|head -n1)

# see if we need to stop the ntp daemon
pidof ntpd >/dev/null 2>&1
if [ $? -eq 0 ]; then
  /etc/init.d/ntpd stop >/dev/null 2>&1 || exit 1
  restart_ntp=1
fi

# do something with this output
output=$(ntpdate -d $server 2>&1)

# restart the daemon if necessary (distro-specific)
[ -n "$restart_ntp" ] && /etc/init.d/ntpd start >/dev/null 2>&1

Note that the above doesn't actually output anything. You'll have to figure that out yourself. Just be sure to send whatever you get on a single line of output, to make it easier for snmpwalk to parse.

Don't forget to make your script executable:

chmod +x /tmp/get-drift.sh

Then you'd call it (locally) with something like:

snmpwalk -c public -v2c localhost .1.3.6.1.4.1.2021.8.1.101

again, depends on your snmpd config.

Read more on snmp.conf in the man page:

man 5 snmpd.conf

[neelakandan]

Thanks let me try this.b

[neelakandan]

Is there any direct MIB from SNMP for monitoring the NTP time difference

[neelakandan]

I am able to get the drift value using the above method. but still trying to find a MIB for NTP monitoring.someone help please