Ubuntu 24.04 LTS – chrony reports unsynchronized system clock

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Time drift causes auth, TLS, and scheduler reliability issues.

Environment & Reproduction

Observed when NTP sources are unreachable or blocked.

chronyc tracking
chronyc sources -v

Root Cause Analysis

chronyd lacks usable upstream peers or cannot correct drift due to policy/network issues.

Quick Triage

Validate chrony service status and source reachability.

systemctl status chrony --no-pager
chronyc sources -v

Step-by-Step Diagnosis

Inspect chrony config and recent sync-related logs.

sudo grep -v '^#' /etc/chrony/chrony.conf | sed '/^$/d'
sudo journalctl -u chrony -n 80 --no-pager

Solution – Primary Fix

Configure valid NTP servers and restart chrony.

sudo sed -i 's/^pool /#pool /' /etc/chrony/chrony.conf
echo 'server  iburst' | sudo tee -a /etc/chrony/chrony.conf
sudo systemctl restart chrony

Solution – Alternative Approaches

Use systemd-timesyncd where chrony is not required by policy.

timedatectl status

Verification & Acceptance Criteria

Clock reaches synchronized state and offset stabilizes.

chronyc tracking
chronyc sources -v
timedatectl status

Rollback Plan

Restore prior chrony.conf if new sources are unreliable.

sudo cp /etc/chrony/chrony.conf.bak /etc/chrony/chrony.conf
sudo systemctl restart chrony

Prevention & Hardening

Continuously monitor offset and source reachability.

chronyc sourcestats -v

Related Errors & Cross-Refs

Related to clock skew too great and certificate not yet valid errors.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu chrony and time synchronization documentation.