A Complete Guide to Chrony: The Modern NTP Client for Time Synchronization

Time synchronization is crucial in distributed systems. Whether running servers, cloud infrastructure, or IoT devices, precise timekeeping ensures logs are accurate, processes align, and security is tight. Chrony is an NTP client and server, optimized for modern network environments.

In this guide, we’ll explain why Chrony is the preferred choice over traditional NTP clients like ntpd and how to configure it effectively.

What is Chrony?

Chrony is a lightweight and flexible implementation of the Network Time Protocol (NTP). It maintains accurate system time even under challenging conditions, like:

• Unstable or slow network connections.
• Systems that are often offline or virtualized environments.
• High-latency or intermittent connectivity.

Chrony consists of two key components:

• chronyd: The daemon running in the background to sync time.
• chronyc: A command-line tool to monitor and control chronyd.

Chrony works on Linux and is a strong alternative to traditional ntpd.

Why Use Chrony Over ntpd?

1. Faster Time Synchronization

Chrony can sync time in seconds instead of minutes, making it ideal for systems requiring quick adjustments.

2. Better Accuracy

It compensates for clock drift and handles dynamic frequency adjustments better than ntpd.

3. Works in Unreliable Networks

Chrony’s algorithms adapt well to poor network conditions, making it a favorite for edge devices.

4. Low Resource Consumption

Designed for efficiency, it consumes fewer resources than ntpd.

5. Supports Intermittent Connectivity

If your system goes offline, Chrony can estimate time drift and re-synchronize effectively once reconnected.

Installing Chrony

Chrony is available in most Linux distributions. Install it using your package manager:

For Debian/Ubuntu:

sudo apt update  
sudo apt install chrony  

For RHEL/CentOS/AlmaLinux:

sudo dnf install chrony  

For Fedora:

sudo dnf install chrony  

Once installed, enable and start the Chrony service:

sudo systemctl enable chronyd  
sudo systemctl start chronyd  

Verify that Chrony is running:

sudo systemctl status chronyd  

Configuring Chrony

Chrony’s configuration file is located at /etc/chrony/chrony.conf. Below are some key settings to optimize.

1. Set NTP Servers

Specify the NTP servers to sync with:

server 0.pool.ntp.org iburst  
server 1.pool.ntp.org iburst  
server 2.pool.ntp.org iburst  
server 3.pool.ntp.org iburst  

The iburst option speeds up initial synchronization.

2. Allow Local Network Clients

If your system should act as an NTP server, allow specific networks:

allow 192.168.1.0/24  

3. Enable Logging

Chrony supports extensive logging. Enable it for better troubleshooting:

log tracking measurements statistics  
logdir /var/log/chrony  

4. Adjust System Drift

Chrony compensates for hardware clock drift using the driftfile parameter:

driftfile /var/lib/chrony/drift  

After editing the configuration file, restart the service:

sudo systemctl restart chronyd  

Monitoring Chrony

The chronyc command helps monitor and manage Chrony.

Check Synchronization Status

chronyc tracking  

This shows synchronization accuracy and system drift.

List Active NTP Sources

chronyc sources  

You’ll see a list of NTP servers and their statuses.

Force Manual Synchronization

sudo chronyc makestep  

This forces an immediate synchronization of the system clock.

Best Practices for Chrony

• Use multiple NTP servers for redundancy.
• Configure Chrony on all nodes in a distributed system to avoid time drift.
• Use logging to detect and troubleshoot time sync issues.
• Monitor drift values to assess hardware clock stability.

Why Accurate Time Matters

Accurate time synchronization impacts many areas:

• Security: Time-stamped logs are essential for audits and troubleshooting.
• Distributed Systems: Ensures consistency in tasks like database replication.
• IoT and Edge: Maintains reliable operation of decentralized devices.

Boost Your Reliability with AI

For robust time synchronization and better system reliability, integrate AI tools like BrendanAI. BrendanAI assists with failure prediction, incident analysis, and system optimization. It’s a perfect complement to Chrony for modern SRE workflows.

Conclusion

Chrony offers a superior alternative to traditional NTP solutions, making it a must-have for modern Linux environments. Its flexibility, speed, and precision make it ideal for servers, edge devices, and virtualized systems.

Try Chrony today and ensure your systems are always in sync. Don’t forget to explore BrendanAI for smarter incident management and enhanced reliability.

Stay in control, stay precise. Happy timekeeping!