ntpd fails to sync TIME_ERROR: 0x41: Clock Unsynchronized

Question

On Debian 10, ntpd [email protected] fails to sync with following error:

kernel reports TIME_ERROR: 0x41: Clock Unsynchronize

here's ntp.conf:

disable monitor

statsdir /var/log/ntpstats

restrict -4 default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
restrict 127.0.0.1
restrict ::1

server 0.us.pool.ntp.org iburst
server 1.us.pool.ntp.org iburst
server 2.us.pool.ntp.org iburst
server 3.us.pool.ntp.org iburst

server   127.127.1.0
fudge    127.127.1.0 stratum 10
restrict 127.127.1.0

driftfile /var/lib/ntp/drift

ntpq -c sysinfo:

associd=0 status=0614 leap_none, sync_ntp, 1 event, freq_mode,
system peer:        50-205-57-38-static.hfc.comcastbusiness.net:123
system peer mode:   client
leap indicator:     00
stratum:            2
log2 precision:     -23
root delay:         70.634
root dispersion:    3.569
reference ID:       50.205.57.38
reference time:     e3a0c049.c39d770a  Wed, Jan  6 2021 23:03:37.764
system jitter:      0.723169
clock jitter:       1.177
clock wander:       0.000
broadcast delay:    -50.000
symm. auth. delay:  0.000

ntpq -c lpeers:

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 LOCAL(0)        .LOCL.          10 l  286   64   20    0.000    0.000   0.000
*50-205-57-38-st .GPS.            1 u   19   64   37   70.631    1.618   1.843
-ns1.backplanedn 173.162.192.156  2 u   14   64   37   84.235   -1.575   2.852
+c-73-239-136-18 74.6.168.73      3 u   11   64   37   48.606    1.598   2.522
+time-d.bbnx.net 252.74.143.178   2 u   14   64   37   92.632    0.623   0.799

timedatectl:

               Local time: Wed 2021-01-06 23:06:44 UTC
           Universal time: Wed 2021-01-06 23:06:44 UTC
                 RTC time: Wed 2021-01-06 23:06:44
                Time zone: Etc/UTC (UTC, +0000)
System clock synchronized: no
              NTP service: inactive
          RTC in local TZ: no

Any idea what could be wrong?

Solution

Your clock is syncing fine. The sync_ntp in your ntpq -c sysinfo proves that. The kernel messages you're referring to are transient during ntpd startup and are not anything to be worried about.

The problems I see with your setup:

1. timedatectl is not reporting time sync correctly. The easy fix for that is not to run it. :-) On one of my servers on the same OS and NTP version, timedatectl doesn't produce anything useful at all, but instead says Failed to create bus connection: No such file or directory, because I don't run dbus.
2. I'm surprised your configuration works with pool servers at all, because of the lack of a restrict source ... line.
3. You're using the LOCL clock driver, which has been deprecated for many years.
4. Similarly, you don't need disable monitor to protect yourself from being used for reflective DDoS - the default restrict lines handle that.

You should revert to the default Debian /etc/ntp.conf contents - it will work better than your current configuration and cause you fewer problems when you upgrade. Here's a copy, in case you don't have one handy: http://paste.debian.net/1180011/

Comments

[berndbausch]

Probably nothing is wrong, and it's just a misleading warning message at startup. See, for example, linuxquestions.org/questions/slackware-14/…. Apart from this message, are there any other symptoms that worry you? Is the time correct? This computer seems to get its time from a GPS device, and the difference between GPS time and computer time is a mere millisecond (offset column in the peers table).

[Tombart]

Thanks. I'm worried about kernel reporting unsynced clock. ntp seems to need more time to sync. I've tried using chrony and it reports synced time immediately.