Time sync using chrony

chrony is a versatile implementation of the Network Time Protocol (NTP). It can synchronize the system clock with NTP servers, reference clocks (e.g. GPS receiver), and manual input using wristwatch and keyboard. It can also operate as an NTPv4 (RFC 5905) server and peer to provide a time service to other computers in the network.

• chronyc tracking

  Reference ID    : CB00710F (foo.example.net)
  Stratum         : 3
  Ref time (UTC)  : Fri Jan 27 09:49:17 2017
  System time     : 0.000006523 seconds slow of NTP time
  Last offset     : -0.000006747 seconds
  RMS offset      : 0.000035822 seconds
  Frequency       : 3.225 ppm slow
  Residual freq   : -0.000 ppm
  Skew            : 0.129 ppm
  Root delay      : 0.013639022 seconds
  Root dispersion : 0.001100737 seconds
  Update interval : 64.2 seconds
  Leap status     : Normal
  

  The tracking command displays parameters about the system’s clock performance. An example of the output is shown below.

• chronyc sources

  210 Number of sources = 3
  MS Name/IP address         Stratum Poll Reach LastRx Last sample
  ===============================================================================
  #* GPS0                          0   4   377    11   -479ns[ -621ns] +/-  134ns
  ^? foo.example.net               2   6   377    23   -923us[ -924us] +/-   43ms
  ^+ bar.example.net               1   6   377    21  -2629us[-2619us] +/-  
  

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