Time Synchronization (NTP / Chrony)

Configure automatic time synchronization on your VPS with Chrony or systemd-timesyncd.

An unsynchronized system clock causes problems with SSL, logs, cron jobs and authentication (2FA, JWT, certificates).

Check current status

timedatectl status

Expected output:

System clock synchronized: yes
NTP service: active

If it shows NTP service: inactive or System clock synchronized: no, time synchronization needs to be enabled.

Option 1: systemd-timesyncd (lightweight, already included)

The simplest method: available on Ubuntu 18.04+ and Debian 9+.

# Enable and start service
systemctl enable --now systemd-timesyncd

# Verify
timedatectl timesync-status

Configure NTP servers in /etc/systemd/timesyncd.conf:

[Time]
NTP=0.pool.ntp.org 1.pool.ntp.org 2.pool.ntp.org
FallbackNTP=ntp.ubuntu.com

systemctl restart systemd-timesyncd

Option 2: Chrony (recommended for production servers)

Chrony is more precise and adapts better to network variations.

Installation

# Debian / Ubuntu
apt install chrony -y

# AlmaLinux / CentOS
dnf install chrony -y

Configuration

nano /etc/chrony.conf

# Public NTP servers (pool.ntp.org)
pool 0.pool.ntp.org iburst maxsources 2
pool 1.pool.ntp.org iburst maxsources 2
pool 2.pool.ntp.org iburst maxsources 2

# Permit rapid slew if offset > 1s
makestep 1.0 3

# Drift file
driftfile /var/lib/chrony/drift

# Log
logdir /var/log/chrony

systemctl enable --now chronyd

# Verify synchronization
chronyc tracking
chronyc sources -v

Output of chronyc tracking:

Reference ID    : 85.21.78.91 (ntp1.example.net)
Stratum         : 2
System time     : 0.000012345 seconds fast of NTP time
Last offset     : +0.000009123 seconds
RMS offset      : 0.000008234 seconds
Frequency       : 12.345 ppm slow

Set timezone

# List available timezones
timedatectl list-timezones | grep Europe

# Set (example: Rome)
timedatectl set-timezone Europe/Rome

# Verify
date

Resolve misaligned clock

If the clock is very different from the real time:

# With Chrony: force immediate synchronization
chronyc makestep

# With systemd-timesyncd: restart service
systemctl restart systemd-timesyncd
timedatectl set-ntp true

Slew vs Step

By default, Chrony corrects the clock gradually (slew) to not disturb logs. If you have an offset greater than 3 seconds, use chronyc makestep to correct immediately.

Final verification

timedatectl status
date
chronyc tracking   # if using Chrony

All correct if you see synchronized: yes and the local time matches.

Time Synchronization (NTP / Chrony)

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