check_linux_timesync

Nagios and Icinga2 plugin to check status of the local timesync client. Currently supported timesync clients are systemd-timesyncd and chronyc.

Dependencies

This plugin requires:

• one of the following running timesync-clients:
  • chronyc
  • systemd-timesyncd
• Python3

Notes

• timedatectl provides less details and insights regarding the configured sources, their state and the dispersion and delay for example. Therefore there are less metrics available for systemd-timesyncd.
• chronyc offers a lot of metrics and details regarding the configured sources. See docs.fedoraproject.org for a chrony monitoring guide.
• leap_status is used as alias for the sync status of any timesync client (not only chrony, where you find Leap status in the output of chronyc tracking.
• The thresholds are currently not configurable! So any of the following condition can raise an alarm:
  • conditions for the plugin to succeed (-> exit status OK)
    • chronyc
    • if the client is synced
    • if there are no falsetickers
    • if less than half of the configured sources are available
  • conditions for warning alarms
    • chronyc
    • if any false ticking sources are found and the number of those falsetickers is less than the number of configured sources
    • if the number of unavailable sources is greater than configured sources / 2 and less than configured sources
    • systemd-timesyncd
    • None
  • conditions for critical alarms
    • chronyc
    • if the client is not synced (leap_status = 2)
    • if all configured sources are tagged as falseticker (see chronyc sources)
    • if 50% or less of the configured sources are unavailable
    • sytemd-timesyncd
    • if the client is not synced (leap_status = 2)

How it works

chronyc checks

The plugin uses chronyc -c with the chosen resource (falseticker, leap_status, sources) as argument and parses the output.

systemd-timesyncd checks

The plugin uses timedatectl status command and checks the value of NTP synchronized or System clock synchronized which is used on older versions.

Performance data

This plugin provides different metrics depending on the timesync client and checked resource.

chronyc performance data

Performance data per resource:

• leap_status
  • leap_status (which matches the plugin exit status: 0 = synced; 2 = not synced)
  • max_estimated_error
• falseticker
  • configured_sources
  • falseticker_sources
• sources
  • available_sources
  • configured_sources
  • synchronized_sources
  • unavailable_sources
  • unreliable_sources

systemd-timesyncd

Only the leap status of the systemd-timesyncd client is monitored. Available metrics:

• leap_status

Usage

See the examples below or execute the plugin with -h/--help.

Examples

Check systemd-timesyncd leap_status:

./check_linux_timesync_status  -d systemd-timesyncd
LEAP STATUS OK - System clock is in sync | leap_status=0;0;2;;2

Check chronyc falseticker:

./check_linux_timesync_status  -d chronyc -r falseticker
NTP FALSETICKER STATUS OK - No falseticker found | falseticker_sources=0;0;4;;4 configured_sources=4;0;4;;

Check chronyc leap_status:

./check_linux_timesync_status  -d chronyc
LEAP STATUS OK - System clock is in sync. | leap_status=0;0;2;;2 max_estimated_error=0.019269515;0;;;

Check chronyc sources with 4 configured sources:

./check_linux_timesync_status  -d chronyc -r sources
NTP SOURCES STATUS OK - 4 out of 4 sources are available; 1 synchronized source | available_sources=4;0;4;2;0 synchronized_sources=1;0;4;; unavailable_sources=0;0;4;2;3 unreliable_sources=0;0;4;; configured_sources=4;0;4;;