How to sync NTP time with chrony

chrony is a network time protocol (NTP) implementation. It can be used to keep server time sync with NTP servers.

To install chrony on RHEL based OS, run

yum install chrony

On Debian/Ubuntu, run

apt install chrony

Configure chrony

On Ubuntu, by default chrony is configured to use ubuntu NTP servers.

pool ntp.ubuntu.com        iburst maxsources 4
pool 0.ubuntu.pool.ntp.org iburst maxsources 1
pool 1.ubuntu.pool.ntp.org iburst maxsources 1
pool 2.ubuntu.pool.ntp.org iburst maxsources 2

If you need to change NTP servers, you can edit configuration file

vi /etc/chrony/chrony.conf

Restart chrony

systemctl restart chrony

Enable chrony

systemctl enable chrony

Start chrony

systemctl start chrony

To view status, run

systemctl status chrony

Display system time information, you can use the command “chronyc tracking”.

root@ip-172-26-14-120:~# chronyc tracking
Reference ID    : E9485C92 (prod-ntp-4.ntp4.ps5.canonical.com)
Stratum         : 3
Ref time (UTC)  : Sat Jun 10 08:15:27 2023
System time     : 0.000015639 seconds slow of NTP time
Last offset     : -0.000025658 seconds
RMS offset      : 0.000170312 seconds
Frequency       : 4.834 ppm fast
Residual freq   : -0.007 ppm
Skew            : 0.255 ppm
Root delay      : 0.008501955 seconds
Root dispersion : 0.001060591 seconds
Update interval : 260.2 seconds
Leap status     : Normal
root@ip-172-26-14-120:~# 

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