Check ntp-ntpd

Overview

This plugin checks the clock offset of ntpd in milliseconds compared to ntp servers. It also prints

  • remote: address of the remote peer

  • refid: reference ID (0.0.0.0 if this is unknown)

  • st: stratum of the remote peer

  • t: type of the peer (local, unicast, multicast or broadcast)

  • when: when the last packet was received

  • poll: polling interval in seconds

  • reach: reachability register in octal

  • delay: estimated delay

  • offset: estimated offset

  • jitter: dispersion of the peer

ntpd is deprecated on RHEL 8+.

The stratum of the NTP time source determines its quality. The stratum is equal to the number of hops to a reference clock (which is stratum 0). A NTP server connected directly to the reference clock is Stratum 1, a client connected to this NTP server is Stratum 2, etc.

Fact Sheet

Check Plugin Download

https://github.com/Linuxfabrik/monitoring-plugins/tree/main/check-plugins/ntp-ntpd

Check Interval Recommendation

Once a minute

Can be called without parameters

Yes

Compiled for

Linux

Help

usage: ntp-ntpd [-h] [-V] [-c CRIT] [--test TEST] [-w WARN]

This plugin checks the clock offset of ntpd in milliseconds compared to ntp
servers.

options:
  -h, --help            show this help message and exit
  -V, --version         show program's version number and exit
  -c CRIT, --critical CRIT
                        Set the critical threshold for the ntp time offset, in
                        ms. Default: 86400000ms
  --test TEST           For unit tests. Needs "path-to-stdout-file,path-to-
                        stderr-file,expected-retc".
  -w WARN, --warning WARN
                        Set the warning threshold for the ntp time offset, in
                        ms. Default: 800ms

Usage Examples

./ntp-ntpd --warning 500 --critical 10000

Output:

NTP offset is -3.005ms, Stratum is 2

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+host234-254-110 131.188.3.221    2 u   51   64   77   77.863   -7.828  19.747
+a-na27-74.tin.i 80.20.16.52      5 u   42   64  177  107.243  -10.797 108.288
-time.cloudflare 10.19.9.88       3 u   43   64  177  262.432  -106.25  64.326
*ns3.fiberteleco 192.168.10.2     2 u   13   64  377   56.901   -3.005  33.579

States

  • WARN or CRIT if ntp offset is below or above a given threshold.

  • WARN if stratum is >= 9.

  • WARN if no NTP server is used.

  • WARN if no NTP server is found.

  • WARN if only LOCAL clock is used.

Perfdata / Metrics

Name

Type

Description

delay

Milliseconds

Delay in ms

jitter

Milliseconds

Jitter in ms

offset

Milliseconds

Time offset in ms

stratum

Number

Stratum

Troubleshooting

OS Error „2 No such file or directory“ calling command „ntpq -p“

You don’t have ntpd.

ntpq: read: Connection refused

ntpd is not running.

No NTP server used.

This message occurs when ntpd is running, and ntpd does (currently) not use any ntp server.

Credits, License