Time Drift on RHEL 9 with chronyd

📖 ~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 drifts, causing TLS validation failures and inconsistent distributed application behavior.

Environment & Reproduction

Run systemctl status chronyd, chronyc tracking, and chronyc sources -v to inspect synchronization health.

Root Cause Analysis

NTP sources are unreachable, blocked by firewalld, or configuration points to unreliable upstream servers.

Quick Triage

Update /etc/chrony.conf to trusted sources, open required firewall egress, and restart chronyd.

Step-by-Step Diagnosis

Capture high offset, root delay, and source state before changes.

Solution – Primary Fix

chronyc tracking shows low offset and selected source marked with an asterisk.

Solution – Alternative Approaches

Observe tracking metrics over time and confirm application timestamps remain consistent.

Verification & Acceptance Criteria

Use multiple internal NTP sources and monitor offset thresholds continuously.

Rollback Plan

Reapply prior chrony source list if new servers are unstable.

Prevention & Hardening

Manage chrony configuration and service state with declarative automation.

Related Errors & Cross-Refs

Review journalctl -u chronyd and chrony measurements for source selection changes.

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

Provide chronyc outputs, firewall policy, and source reachability checks.