Chronyd Not Synchronizing Time on RHEL 9 edition

📖 ~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

timedatectl shows system clock unsynchronized for extended periods.

Environment & Reproduction

Run chronyc sources -v and timedatectl status.

Root Cause Analysis

Determine if issue is NTP server reachability or chronyd configuration.

Quick Triage

Invalid server entries, blocked UDP 123, or stale chronyd state.

Step-by-Step Diagnosis

Correct /etc/chrony.conf server lines and confirm DNS resolution.

Solution – Primary Fix

Restart with systemctl restart chronyd and recheck chronyc tracking.

Solution – Alternative Approaches

Ensure systemctl is-active chronyd returns active and stable.

Verification & Acceptance Criteria

Open outbound UDP 123 and verify upstream NTP availability.

Rollback Plan

Default SELinux policy supports chronyd; check only custom hardening changes.

Prevention & Hardening

Review journalctl -u chronyd for source rejection or timeout messages.

Related Errors & Cross-Refs

Use at least three reliable time sources and monitor drift alerts.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Restore prior chrony.conf and restart chronyd if new config fails.