🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026

📖 ~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

Clock drift on RHEL 7 breaks authentication, logging order, and scheduled jobs when time synchronization service is inactive.

Environment & Reproduction

TLS errors, Kerberos issues, and mismatched timestamps appear across applications and journalctl output.

Root Cause Analysis

chronyd or ntpd disabled, unreachable NTP sources, firewall blocking UDP 123, or incorrect timezone setup.

Quick Triage

Check timedatectl, inspect systemctl status chronyd, and verify service chronyd status where legacy scripts are used.

Step-by-Step Diagnosis

Collect journalctl -u chronyd and synchronization statistics to confirm service inactivity or source rejection.

Illustrative mockup for rhel-7 — rhel7-137-chrony-journalctl-stopped.webp
journalctl output showing chronyd or ntpd inactive state — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Review chrony.conf server directives and ensure reachable upstream pools are defined for your environment.

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Illustrative mockup for rhel-7 — rhel7-137-chrony-conf-sources.webp
chrony configuration with valid upstream time sources — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Enable and start chronyd with systemctl, open required firewall path if needed, then validate stable time sync.

Verification & Acceptance Criteria

SELinux rarely blocks chronyd defaults, but firewalld must allow NTP traffic according to security policy.

Rollback Plan

Confirm synchronized status, monitor drift values, and verify dependent services recover from time-related errors.

Prevention & Hardening

If new time sources fail, revert to previous source list and re-enable last stable synchronization profile.

Continuously monitor offset metrics and alert when chrony service state changes from active.

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 chrony and RHEL time synchronization guides for enterprise-safe NTP configuration.

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