RHEL 9 Chronyd Not Synchronizing Time

📖 ~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 grows because chronyd is not synchronizing on RHEL 9.

Environment & Reproduction

chronyc reports unsynchronized status, TLS services fail, and Kerberos tokens become invalid.

Root Cause Analysis

NTP sources are unreachable, blocked by firewalld, misconfigured in chrony.conf, or chronyd is inactive.

Quick Triage

Run ‘timedatectl’ and ‘chronyc tracking’ to confirm if the clock is synchronized.

Step-by-Step Diagnosis

Use ‘chronyc sources -v’ to identify unreachable servers and high offset peers.

Solution – Primary Fix

Execute ‘sudo systemctl restart chronyd’ then ‘chronyc tracking’ to verify recovery.

Solution – Alternative Approaches

Allow NTP when needed with firewalld and ensure upstream UDP/123 connectivity in network controls.

Verification & Acceptance Criteria

Validate source hostnames resolve correctly and outbound routes reach designated time servers.

Rollback Plan

SELinux rarely blocks chronyd defaults, but inspect AVC logs if custom paths or services were introduced.

Prevention & Hardening

Use ‘sudo journalctl -u chronyd –no-pager -n 100’ for source selection and step/slew errors.

Related Errors & Cross-Refs

For large drift, use ‘sudo chronyc makestep’ in approved maintenance windows before sensitive workloads resume.

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

Configure multiple trusted NTP sources and monitor tracking offset to catch drift early.