NTP synchronisation not visible in syslog

Solution 1:

NTP is normally very quiet/silent in syslog. Things are going wrong if it shows up. If your hardware clock is working, it shouldn't need to modify your clock during startup. With the right settings it can replace ntpdate to set the clock on startup if required.

The logs you want to look at are the loopstats and peerstats files. Once running NTP should not need to synchronize the clock. It will adjust the tick timing very slightly to keep the clock synchronized. loopstats file provides your local state, while peerstats shows your state relative to the servers you are using. See the NTP Troubleshooting Guide for details on these files.

Solution 2:

Just for confirming that the system is synchronized the following can be executed:

# ntpq -pn
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 159.69.144.253  94.16.116.137    3 u   60   64   37    2.749   -2.464   0.066
*176.9.241.107   192.53.103.108   2 u   61   64   37    0.461    0.237   0.026
 193.175.73.20   .MRS.            1 u   62   64   37   19.189    1.786   0.072
 138.68.126.106  130.149.17.8     2 u   59   64   37    5.366    0.562   0.043

Where an * suffix for a record indicates that that peer is currently being used for synchronization.

In the other hand, for detailed monitoring/logging of clock synchronization events, I found the following to be quite helpful:

First, create the following folder if it doesn't exist and assign it ownership to the user running the NTP daemon:

# mkdir /var/NTP/
# chown ntp /var/NTP/

Now modify ntp.conf like this where the meaning of each one of these entries is explained in http://doc.ntp.org/4.2.6p3/monopt.html:

statsdir /var/NTP/
filegen clockstats file clockstats
filegen cryptostats file cryptostats
filegen loopstats file loopstats
filegen peerstats file peerstats
filegen protostats file protostats
filegen rawstats file rawstats
filegen sysstats file sysstat
filegen timingstats file timingstats

Then restart the NTP service and look at the /var/NTP/ folder.

Finally, for example, to determine the peers that has been used for synchronization as time goes, look for lines ending in sys_peer in /var/NTP/protostats, e.g.:

58827 80454.306 159.69.144.253 8014 84 reachable
58827 80647.304 176.9.241.107 901a 8a sys_peer
58827 80647.304 0.0.0.0 c615 05 clock_sync
58827 80842.323 193.175.73.20 901a 8a sys_peer

PS:

• I'm not a NTP expert, so I could be wrong in some of the previous statements.