Category:	Utilities
Price:	Free
Popularity:	Low
Version String:	1.5.0 (320)
Release Date:	2024-09-03
Architecture:	Intel & AppleSilicon(ARM)
Minimum OS:	macOS 10.13
Vendor Name:	Bryan Christianson
Homepage:	whatroute.net

Description:

macOS includes ntpd, probably the most widely used software for keeping a computer clock synchronised with other computers/clocks on the internet. However, unless the Mac is online for extended periods of time, ntpd can be very slow to synchronise with other clocks and the system time may be at wild variance with true time.

The chrony software addresses the issues associated with ntpd. This is fully explained in the FAQ

chrony has now been ported to MacOS X, and I have written a tool, ChronyControl, that will provide a straight forward means of installing and monitoring the daemon.


Files Installed by ChronyControl

ChronyControl will install the chrony software and associated files on your Macintosh

• chronyd - /usr/local/bin
• chronyc - /usr/local/bin
• chronylogrotate.sh - /usr/local/bin
• chrony.conf - /etc/chrony.d/chrony.conf
• launchd plist - /Library/LaunchDaemons/org.tuxfamily.chronyd.plist
• launchd plist - /Library/LaunchDaemons/org.tuxfamily.chronyc.plist
• privileged helper - /Library/PrivilegedHelperTools/net.whatroute.chronycontrol

After installation you can also monitor and configure the chrony software from the command line, as you would on any other Unix system. The commands are documented at the chrony website.


ChronyControl

ChronyControl is primarily a front end to the chronyc tool delivered with the chrony software. It can show the overall server performance (tracking) and the state of individual remote time servers

ChronyControl bundles the most recent version of chrony (chronyc and chronyd) and, via the Settings button, can configure and install chronyd.

The upper clock displays the current time of your Mac. The centre hub of the clock will be red if chronyd is not running, orange if the daemon is running but is in an unsynchronised state, and green when chronyd is synchronised and disciplining the system clock.

The chronyc popup button enables you choose between the tracking, sources and sourcestats chronyc commands.

The popup button labeled Last offset below the performance meter in the screenshot, sends the corresponding value from the output of the tracking command to the meter.

Click the padlock icon (you'll be prompted for your login/password) to enable the Settings button.


MacOS X Date & Time

ChronyControl will disable "Set date and time automatically" in the System Preferences "Date & Time" panel. This terminates the ntpd daemon and prevents it from running. If you re-enable the setting, there is no guarantee as to which daemon, ntpd or chronyd, will be disciplining the system clock. Should you wish to go back to using ntpd, you should Uninstall chronyd (see below in ChronyControl Settings) before re-enabling the option in System Preferences.


Rotating chronyd logs

chronyd will (by default although this may be adjusted in the chrony.conf settings file) store statistics to the log files in the directory /var/log/chrony . ChronyControl installs a launchd job to rotate these logs on a daily basis, deleting the oldest (10 days) files.


ChronyControl Settings

These are privileged operations. You must first authenticate by pressing the small padlock in the lower left corner of the window in order to be able to use the Settings button to display the window.


Tracking Graphs

The values shown in the tracking display can be displayed graphically as shown in the screen shots below. Select Tracking from the Windows menu to display the graphs.
The source of data for these graphs is the log file /var/log/chrony/tracking.log
The graph is updated in real time as chronyd adds records to the log file.
Explanation of the colours and data range settings can be seen by clicking the Legend button as shown in the second screen shot.
Controls on the right hand side can be used to zoom/re-scale the graph for either finer granularity or to gain an overview of the data.