How do I check Linux system's current NTP configuration?

[Raj]

I need to list the current NTP configuration on CentOS Linux 8 server. There is no GUI. It is a server. So I need commands to display current status and how can I view NTP configuration?

[nixcraft]

You need to use the timedatectl command. Make sure you run all command as root user (e.g. sudo command).

Get current overview of NTP, date/time and other settings

timedatectl

List or change timezones

timedatectl list-timezones
timedatectl list-timezones | more
timedatectl list-timezones | grep Asia

Set timezone to Asia/Kolkata

timedatectl set-timezone {TIME/ZONE_HERE}
timedatectl set-timezone Asia/Kolkata

Enable or disable NTP synchronization for automatic time adjustment on CentOS 8 Linux

timedatectl set-ntp true
timedatectl set-ntp false

Verify NTP time sync status

timedatectl timesync-status

Install and enable chronyd service

yum install chrony
# check config and make sure NTP server set correctly
vim /etc/chrony.conf

Sample config for CentOS 8 NTP server

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
pool 2.centos.pool.ntp.org iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3

# Enable kernel synchronization of the real-time clock (RTC).
rtcsync

# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *

# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2

# Allow NTP client access from local network.
#allow 192.168.0.0/16

# Serve time even if not synchronized to a time source.
#local stratum 10

# Specify file containing keys for NTP authentication.
keyfile /etc/chrony.keys

# Get TAI-UTC offset and leap seconds from the system tz database.
leapsectz right/UTC

# Specify directory for log files.
logdir /var/log/chrony

# Select which information is logged.
#log measurements statistics tracking

Enable and start the chronyd service:

systemctl enable chronyd
systemctl start chronyd
systemctl status chronyd
# verify that NTP is working #
timedatectl
chronyc sources -v

Please note that chronyd service not required on CentOS 8 but can be used for NTP. See chrony – Documentation for more information.