The utility can also be invoked in non-interactive command mode if called together with a command as follows: This option logs information about the regression processing to a file called statistics. The default configuration is for chronyd to only accept commands from a local instance of chronyc , but chronyc can be used to alter the configuration so that chronyd will allow external control. The default value is 3 seconds and the maximum value is seconds. This allows the maxdelay option for one of the sources to be modified, in the same way as specifying the maxdelay option for the server directive in the configuration file see section server.

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Std Dev This is the estimated sample standard deviation. Try using the ps command e. If ntpd is used as the broadcast client, it will try to measure the round-trip delay between the server and client with normal client mode packets.

chrony – Frequently Asked Questions

And you must show them these terms so chorny know their rights. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. However, you will probably want to include some of the other directives described later. An example of how to do this is shown below. The interleaved mode is compatible with servers that support only the basic mode, but peers must both support and have enabled the interleaved mode, otherwise the synchronisation will work only in one direction.

Real-time clock issues 5. You could then persuade the firewall administrator to open that port. This is similar to the cmdallow directive, except that it denies monitoring access to a particular subnet or host, rather than allowing it. This option also effectively disables server support for the NTP interleaved mode.


c h r o n y

Rrtc are two forms of the directive. Setting Up chrony for a System in an Isolated Network For a network that is never connected to the Internet, one computer is selected to be the master timeserver. This defines the maximum number of measurements that chronyd will attempt to make, even if the required number of good measurements has not been obtained.

However, other locations can be specified with a command line option. This should not impact performance as chronyd’s resource requirements are modest, but it should result in lower and more consistent latency since chronyd will not need to wait for the scheduler to get around to running it.

To illustrate the effect, consider chrny two examples: The default value is e-9 nanoseconds. For a complete list of the directives that can be used see https: The default value is 8.

This would send a mail message to root if a change of more than 0.

The smoothing process needs to be activated by the smoothtime activate command when the local time is ready to be served. The purpose chront the initstepslew directive is to allow chronyd to make a rapid measurement of the system clock error at boot time, and to correct the system clock by stepping before normal operation begins. Each of the servers is rapidly polled several times, chrny a majority voting mechanism used to find the most likely range of system clock error that is present.

Configuring NTP Using the chrony Suite :: Fedora Docs Site

This feature needs to be used carefully, because the server is intentionally not serving its best estimate of the true time. The stratum indicates how many hops away from a computer with an attached reference clock we are. The first three options set the minimum and maximum allowed polling interval, and how should be the actual interval adjusted in the specified range.


A comment line is any line that starts with zero or more spaces followed by any one of the following characters: When chronyd is slewing the system clock ftc correct an offset, the rate at which it is slewing adds to the frequency error of the clock.

The bindacqaddress directive sets the network interface to which will chronyd bind its NTP client sockets.

Chrony consists of chronyda daemon that runs in user space, and chronyca command line program for making adjustments to chronyd. The second form configures the automatic stepping, similarly to the makestep directive see section makestep. It is independent from any slewing applied to the local system clock, but the accumulated offset and frequency will be reset when the clock is corrected by stepping, e.

A value which is small indicates that the measurements are not well approximated by a linear model, and that the algorithm will tend to delete the older measurements to improve the fit. This option specifies the minimum number of readings kept for tracking of the NIC clock. If a curony offset has been accumulated, it may take a very long time to smooth it out.