Chronyd Not Synchronizing Time on RHEL 9

📖 ~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 clock drift causes auth failures, TLS errors, or clustered service instability.

Environment & Reproduction

chronyd is inactive, upstream NTP blocked by firewalld, or NTP servers misconfigured.

Root Cause Analysis

Run: timedatectl and chronyc tracking to inspect synchronization status.

Quick Triage

Check chronyd unit state and ensure UDP 123 is not blocked for outbound sync.

Step-by-Step Diagnosis

Capture chronyc sources output indicating unreachable or falseticker servers.

Solution – Primary Fix

Capture healthy source selection and low offset after correction.

Solution – Alternative Approaches

Enable service: sudo systemctl enable –now chronyd.

Verification & Acceptance Criteria

Set valid NTP servers in /etc/chrony.conf, then run sudo systemctl restart chronyd.

Rollback Plan

Force quick sync check: chronyc makestep and monitor tracking metrics.

Prevention & Hardening

timedatectl should report System clock synchronized: yes and NTP service: active.

Related Errors & Cross-Refs

Use internal redundant NTP sources and monitor clock offset across all nodes.

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 previous chrony.conf backup if new source list causes instability.