RHEL 9 Time Drift Due To chronyd Not Syncing

📖 ~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 clocks drift and TLS or Kerberos authentication intermittently fails.

Environment & Reproduction

chronyd is stopped, sources are unreachable, or NTP traffic is blocked by firewalld.

Root Cause Analysis

Run timedatectl, chronyc sources -v, and sudo systemctl status chronyd.

Quick Triage

Ensure service starts at boot using sudo systemctl enable –now chronyd.

Step-by-Step Diagnosis

Update /etc/chrony.conf with reachable pools and allow outbound UDP 123 if restricted.

Solution – Primary Fix

Restart chronyd and force a step when needed using sudo chronyc makestep.

Solution – Alternative Approaches

Confirm stratum and offset stabilize with chronyc tracking and chronyc sources.

Verification & Acceptance Criteria

Reapply prior chrony.conf from backup if new sources introduce unstable offsets.

Rollback Plan

Use multiple regional NTP sources and standardize chrony settings across hosts.

Prevention & Hardening

Monitor NTP offset thresholds and chronyd service state in your observability stack.

Related Errors & Cross-Refs

Deploy chrony baseline via system roles and verify with post-task chronyc probes.

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

See man chronyd, man chronyc, and RHEL 9 time synchronization guidance.