[chrony-users] about drift

[chengyechun <chengyechun1@xxxxxxxxxx>]

Hi all:

When I use chrony-4.1 to synchronize time, the configuration is normal. However, the response packets are different. Is it because the value of /var/lib/chrony/drift is too large? Why is no error displayed in this case? The status of the server is as follows:

 

● chronyd.service - NTP client/server

     Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled; vendor preset: enabled)

     Active: active (running) since Sun 2022-11-13 20:18:54 CST; 7s ago

       Docs: man:chronyd(8)

             man:chrony.conf(5)

    Process: 36942 ExecStart=/usr/sbin/chronyd $OPTIONS (code=exited, status=0/SUCCESS)

   Main PID: 36948 (chronyd)

      Tasks: 1 (limit: 21081)

     Memory: 552.0K

     CGroup: /system.slice/chronyd.service

             └─ 36948 /usr/sbin/chronyd

 

Nov 13 20:18:54 localhost.localdomain systemd[1]: Starting NTP client/server...

Nov 13 20:18:54 localhost.localdomain chronyd[36948]: chronyd version 4.1 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SIGND +ASYNCDNS +NTS +SECHASH +IPV6 +DEBUG)

Nov 13 20:18:54 localhost.localdomain chronyd[36948]: Frequency 9.273 +/- 1000000.000 ppm read from /var/lib/chrony/drift

Nov 13 20:18:54 localhost.localdomain systemd[1]: Started NTP client/server.

 

The following figure shows the packet capture result.

 

dropped privs to tcpdump

tcpdump: listening on enp3s0, link-type EN10MB (Ethernet), snapshot length 262144 bytes

20:23:46.383154 IP (tos 0x0, ttl 64, id 46046, offset 0, flags [DF], proto UDP (17), length 76)

    9.82.217.178..59316 > localhost.localdomain.ntp: [udp sum ok] NTPv4, Client, length 48

        Leap indicator:  (0), Stratum 0 (unspecified), poll 1 (2s), precision 32

        Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID: (unspec)

          Reference Timestamp:  0.000000000

          Originator Timestamp: 0.000000000

          Receive Timestamp:    0.000000000

          Transmit Timestamp:   1552568142.715883743 (1949-03-14T12:55:42Z)

            Originator - Receive Timestamp:  0..000000000

            Originator - Transmit Timestamp: 1552568142.715883743 (1949-03-14T12:55:42Z)

20:23:48.408159 IP (tos 0x0, ttl 64, id 42224, offset 0, flags [DF], proto UDP (17), length 76)

    9.82.217.178..43237 > localhost.localdomain.ntp: [udp sum ok] NTPv4, Client, length 48

        Leap indicator:  (0), Stratum 0 (unspecified), poll 1 (2s), precision 32

        Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID: (unspec)

          Reference Timestamp:  0.000000000

          Originator Timestamp: 0.000000000

          Receive Timestamp:    0.000000000

          Transmit Timestamp:   2742648526.447884985 (1986-11-29T14:48:46Z)

            Originator - Receive Timestamp:  0..000000000

            Originator - Transmit Timestamp: 2742648526.447884985 (1986-11-29T14:48:46Z)

20:23:50.423951 IP (tos 0x0, ttl 64, id 21064, offset 0, flags [DF], proto UDP (17), length 76)

    9.82.217.178..50545 > localhost.localdomain.ntp: [udp sum ok] NTPv4, Client, length 48

        Leap indicator:  (0), Stratum 0 (unspecified), poll 1 (2s), precision 32

        Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID: (unspec)

          Reference Timestamp:  0.000000000

          Originator Timestamp: 0.000000000

          Receive Timestamp:    0.000000000

          Transmit Timestamp:   3202229013.548778843 (2001-06-22T20:03:33Z)

            Originator - Receive Timestamp:  0..000000000

           Originator - Transmit Timestamp: 3202229013.548778843 (2001-06-22T20:03:33Z)

 

3 packets captured

6 packets received by filter

0 packets dropped by kernel