About the chronyc Service Utility

The chronyc utility is a tool for managing the chronyd service, displaying information about the service's operation, or changing the service's configuration.

The command operates in two modes:

  • Non interactive mode: In this mode, you use the following syntax:

    sudo chronyc subcommand
  • Interactive mode: Typing the command by itself activates the interactive mode and displays the chronyc> prompt. From this prompt you can issue chronyc subcommands.

    sudo chronyc
    chronyc>

    From the prompt, you can issue the different chronyc subcommands as needed. The following examples show the information that's generated by the sources, sourcestats, and tracking subcommands:

    chronyc> sources
    210 Number of sources = 4
    MS Name/IP address         Stratum Poll Reach LastRx Last sample
    ===============================================================================
    ^+ service1-eth3.debrecen.hp     2   6    37    21  -2117us[-2302us] +/-   50ms
    ^* ns2.telecom.lt                2   6    37    21   -811us[ -997us] +/-   40ms
    ^+ strato-ssd.vpn0.de            2   6    37    21   +408us[ +223us] +/-   78ms
    ^+ kvm1.websters-computers.c     2   6    37    22  +2139us[+1956us] +/-   54ms
    chronyc> sourcestats
    210 Number of sources = 4
    Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
    ==============================================================================
    service1-eth3.debrecen.hp   5   4   259     -0.394     41.803  -2706us   502us
    ns2.telecom.lt              5   4   260     -3.948     61.422   +822us   813us
    strato-ssd.vpn0.de          5   3   259      1.609     68.932   -581us   801us
    kvm1.websters-computers.c   5   5   258     -0.263      9.586  +2008us   118us
    
    chronyc> tracking
    
    Reference ID    : 212.59.0.2 (ns2.telecom.lt)
    Stratum         : 3
    Ref time (UTC)  : Tue Sep 30 12:33:16 2014
    System time     : 0.000354079 seconds slow of NTP time
    Last offset     : -0.000186183 seconds
    RMS offset      : 0.000186183 seconds
    Frequency       : 28.734 ppm slow
    Residual freq   : -0.489 ppm
    Skew            : 11.013 ppm
    Root delay      : 0.065965 seconds
    Root dispersion : 0.007010 seconds
    Update interval : 64.4 seconds
    Leap status     : Normal

    To quit using the interactive mode, type exit.

Note:

Any changes you implement with the chronyc command are effective only until the next restart of the chronyd daemon. To make the changes permanent, you must enter these in the /etc/chrony.conf file. See chronyd Configuration File Examples.

For more information, see the chronyc(1) manual page and files in the /usr/share/doc/chrony/ directory.