🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: RHEL 10.0 RHEL 10.1

📖 ~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

Time drift causes authentication failures, certificate issues, and distributed job instability.

Environment & Reproduction

Common on isolated networks with unreachable NTP sources.

timedatectl
chronyc tracking

Root Cause Analysis

chronyd cannot reach or trust configured servers due to firewall, DNS, or bad source list.

Quick Triage

Validate service state and configured source list.

systemctl status chronyd
grep -E '^(server|pool)' /etc/chrony.conf

Step-by-Step Diagnosis

Inspect source reachability and service logs.

chronyc sources -v
firewall-cmd --list-services
journalctl -u chronyd -n 100
Illustrative mockup for rhel-10 — chrony_diag
Unsynchronized chrony status output — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Set valid NTP servers, ensure UDP 123 access, and restart chronyd.

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sudo sed -i 's/^pool /#pool /' /etc/chrony.conf
echo 'server time.example.net iburst' | sudo tee -a /etc/chrony.conf
sudo systemctl restart chronyd
Illustrative mockup for rhel-10 — chrony_fix
NTP sources corrected and synced — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Use local stratum server for disconnected environments.

Verification & Acceptance Criteria

System reports synchronized clock and stable offset.

timedatectl status
chronyc tracking

Rollback Plan

Revert chrony.conf from backup and restart service.

Prevention & Hardening

Monitor drift thresholds and alert when synchronization state changes.

Related to Kerberos skew errors and TLS handshake validity failures.

Related tutorial: View the step-by-step tutorial for rhel-10.

View all rhel-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Chrony administration guidance for RHEL and enterprise timekeeping.

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