How to Sync Time in CentOS Stream 10 using Chrony

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Chrony is an implementation of the Network Time Protocol. It is used to synchronize the system clock from different NTP servers, reference clocks, or via manual input. It runs on Unix-like operating systems and is released under the GNU GPL v2.

Install Chrony

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To Install Chrony use the following command:

yum install chrony -y

Testing Chrony

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Let's sync the time of our centOS server with the remote NTP server manually. You can get a list of NTP Servers from ntppool.org -- It is recommended to select an NTP server located closest to your server location.

For Europe,

chronyd -q 'server 0.europe.pool.ntp.org iburst'

For North America,

chronyd -q 'server 0.north-america.pool.ntp.org iburst'

Start and Enable Chronyd Service

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Start the chronyd service and setup chronyd to automatically start on reboots using the following commands,

systemctl start chronyd

systemctl enable chronyd

Verify and Track Chrony Synchronization

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Check that your system’s time is synchronized using chrony now.

chronyc tracking

[root@server ~]# chronyc tracking
Reference ID    : 18E52C69 (24-229-44-105-static.cmts.leh2.ptd.net)
Stratum         : 2
Ref time (UTC)  : Thu Feb 20 19:13:09 2025
System time     : 0.000793840 seconds slow of NTP time
Last offset     : -0.000237318 seconds
RMS offset      : 0.002329658 seconds
Frequency       : 42.396 ppm slow
Residual freq   : -0.004 ppm
Skew            : 0.251 ppm
Root delay      : 0.087072112 seconds
Root dispersion : 0.000759991 seconds
Update interval : 64.7 seconds
Leap status     : Normal

From the above output,

• Reference ID is the ID/name of the server with which your system’s time is currently synced.
• Stratum is used here to indicate the number of hops away from the reference clock we are, or simply, the number of hops between us and the remote server we are connected to

Check Chrony Sources

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List time sources used by chronyd.

chronyc sources

[root@server ~]# chronyc sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^+ 72-46-53-234.dia-static.>     3   6   377    64  -1379us[-1379us] +/-   78ms
^+ ntp06.cymru.com               2   6   377    62  -6017us[-6017us] +/-  100ms
^* 24-229-44-105-static.cmt>     1   6   377    64  +8556us[+8696us] +/-   45ms
^+ 143-42-229-154.ip.linode>     2   6   377    64  -3770us[-3770us] +/-   79ms

Check Chrony Source Statistics

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List drift speed and offset estimation of each source that is used by chronyd.

chronyc sourcestats -v

[root@server ~]# chronyc sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^+ 72-46-53-234.dia-static.>     3   6   377    64  -1379us[-1379us] +/-   78ms
^+ ntp06.cymru.com               2   6   377    62  -6017us[-6017us] +/-  100ms
^* 24-229-44-105-static.cmt>     1   6   377    64  +8556us[+8696us] +/-   45ms
^+ 143-42-229-154.ip.linode>     2   6   377    64  -3770us[-3770us] +/-   79ms
[root@server ~]# ^C
[root@server ~]# chronyc sourcestats -v
                             .- Number of sample points in measurement set.
                            /    .- Number of residual runs with same sign.
                           |    /    .- Length of measurement set (time).
                           |   |    /      .- Est. clock freq error (ppm).
                           |   |   |      /           .- Est. error in freq.
                           |   |   |     |           /         .- Est. offset.
                           |   |   |     |          |          |   On the -.
                           |   |   |     |          |          |   samples. \
                           |   |   |     |          |          |             |
Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
==============================================================================
72-46-53-234.dia-static.>  19  12  1040     +0.064      0.421  -1434us   136us
ntp06.cymru.com             8   6   454     +0.072      0.711  -5919us    41us
24-229-44-105-static.cmt>  19  13   975     -0.213      4.755  +6207us  1585us
143-42-229-154.ip.linode>  19   9   975     -1.933      5.376  -4295us  1897us

You have now successfully synced your CentOS Stream 10 times with Chrony.