Using Chrony for time keeping
chrony is the default NTP service supplied with Red Hat Enterprise Linux 7 and newer RHEL versions, so it’s been around for some time. It’s a great Network Time Protocol implementation that is aimed to replace ntpd.
How To Install chrony
There are packages for Linux, FreeBSD, NetBSD, macOS and Solaris. In Red Hat Linux, it gets installed like this:
root@s2:~ # yum install chrony
Check current chrony status
Tracking shows if chrony is currently connected and what server it’s synchronising time from:
root@s2:~ # chronyc tracking Reference ID : C39AAED1 (leeto.nicolbolas.org) Stratum : 3 Ref time (UTC) : Sat Jun 01 22:49:11 2019 System time : 0.000001060 seconds fast of NTP time Last offset : +0.000001358 seconds RMS offset : 0.000014120 seconds Frequency : 14.198 ppm slow Residual freq : +0.000 ppm Skew : 0.060 ppm Root delay : 0.001231604 seconds Root dispersion : 0.000468358 seconds Update interval : 64.9 seconds Leap status : Normal
Check chrony time sources
Sources will report your time synchronisation peers – the time-keepers that your server can get time from. As you can see, the server in previous (tracking) output, leeto.nicolbolas.org, is found on this list of sources as well.
root@s2:~ # chronyc sources 210 Number of sources = 4 MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^* leeto.nicolbolas.org 2 6 377 8 +4139ns[+5545ns] +/- 1749us ^- eterna.binary.net 2 10 377 451 +92us[ +83us] +/- 89ms ^- web01.webhd.nl 3 9 377 206 -362us[ -358us] +/- 78ms ^- 148.ip-193-70-90.eu 3 9 377 139 -3724us[-3723us] +/- 66ms
This should be enough for the first try of using Chrony! Next step will be to setup GPS receiver on becky, Raspberry Pi I have. chronyc sources should report local device differently than a remote server, I think. We’ll see soon enough!