Chronyd Not Syncing 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 drifts and `timedatectl` shows unsynchronized status on RHEL 9 hosts.

Environment & Reproduction

Run `chronyc tracking` and `chronyc sources -v` to inspect source reach and offset.

Root Cause Analysis

Confirm `chrony` package is installed and not replaced by conflicting NTP implementations.

Quick Triage

Use `systemctl status chronyd` and confirm `enabled` state across reboots.

Step-by-Step Diagnosis

Check `journalctl -u chronyd –since -3h` for DNS failures or source selection issues.

Solution – Primary Fix

Backup `/etc/chrony.conf` and current source output before updates.

Solution – Alternative Approaches

Allow UDP 123 as required and verify outbound reachability; inspect `firewalld` egress policy where enforced.

Verification & Acceptance Criteria

SELinux impact is rare, but review AVC logs if custom chrony paths were introduced.

Rollback Plan

Set reliable `server` lines, restart with `systemctl restart chronyd`, and force initial step if needed.

Prevention & Hardening

Confirm `timedatectl status` reports synchronized and offset stabilizes near zero.

Related Errors & Cross-Refs

Use internal NTP tiers and monitor chrony metrics in your observability stack.

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

Attach chrony config, source stats, and packet-level results when sync remains unstable.