chronyd Not Syncing Time on RHEL 7

📖 ~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

chronyd remains unsynchronized on RHEL 7, causing drift that affects logs, TLS, and distributed workloads.

Environment & Reproduction

chronyc tracking reports not synchronized and applications report certificate time or token expiration anomalies.

Root Cause Analysis

Unavailable NTP servers, blocked UDP 123 traffic, incorrect chrony.conf entries, or conflicting time services.

Quick Triage

Run systemctl status chronyd, chronyc sources -v, and verify network route and DNS health before deeper changes.

Step-by-Step Diagnosis

Use journalctl -u chronyd and journalctl -xe to identify reachability, source rejection, or step threshold events.

Solution – Primary Fix

Review /etc/chrony.conf server and allow directives, then test with chronyc makestep where appropriate.

Solution – Alternative Approaches

Set valid NTP servers, restart chronyd, allow UDP 123 through firewalld where needed, and confirm synchronized state.

Verification & Acceptance Criteria

SELinux usually permits chronyd defaults, but firewalld outbound and inbound policy must allow UDP 123 for selected topology.

Rollback Plan

Verify chronyd active state with systemctl status and ensure applications stop reporting time-related failures.

Prevention & Hardening

Restore previous chrony.conf if new server list introduces instability, then restart and re-validate synchronization.

Related Errors & Cross-Refs

Use redundant time sources, monitor drift metrics, and avoid running multiple NTP daemons simultaneously.

Related tutorial: View the step-by-step tutorial for rhel-7.

View all rhel-7 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Refer to chronyd and chronyc manuals and RHEL 7 time synchronization recommendations.