chronyd Not Syncing 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

System time drifts because chronyd cannot synchronize with configured NTP sources.

Environment & Reproduction

timedatectl reports NTP service active but System clock synchronized is no.

Root Cause Analysis

Blocked UDP/123, unreachable sources, bad chrony.conf entries, or virtualization clock issues.

Quick Triage

Check chronyd service, run chronyc sources -v, and verify firewall/proxy policy for NTP.

Step-by-Step Diagnosis

Correct chrony source configuration and restart chronyd using systemctl.

Solution – Primary Fix

Allow UDP/123 where required and confirm source reachability with chronyc tracking.

Solution – Alternative Approaches

Avoid conflicting guest and hypervisor time sync configurations to prevent oscillation.

Verification & Acceptance Criteria

SELinux usually permits chronyd, but custom confinement may require policy review.

Rollback Plan

Validate synchronized status and acceptable offset in chronyc tracking output.

Prevention & Hardening

Return to known-good chrony source set if newly added upstreams are unstable.

Related Errors & Cross-Refs

Use redundant internal NTP sources and monitor offset thresholds.

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

systemctl status chronyd; chronyc sources -v; timedatectl