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

📖 ~1 min read

Table of contents
  1. Problem Summary
  2. Symptoms
  3. Diagnostics
  4. Root Cause
  5. Primary Fix
  6. Verification
  7. Prevention
  8. Rollback
  9. Automation
  10. Command Reference
  11. Escalation
  12. Related Notes

Problem Summary

System clock drifts because chronyd never reaches synchronized state.

Symptoms

timedatectl shows System clock synchronized: no.

Diagnostics

Run chronyc sources -v and systemctl status chronyd.

Root Cause

NTP sources blocked by firewall or incorrect chrony.conf.

Primary Fix

Allow UDP/123 in firewalld and set reliable NTP servers.

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Illustrative mockup for rhel-10 — rhel10-b02-p32-1
Illustrative mockup — Progressive Robot — Illustrative mockup — Progressive Robot

Verification

Check chronyc tracking reports low offset and normal stratum.

Illustrative mockup for rhel-10 — rhel10-b02-p32-2
Illustrative mockup — Progressive Robot — Illustrative mockup — Progressive Robot

Prevention

Use internal NTP hierarchy and source monitoring.

Rollback

Restore previous chrony.conf from config management baseline.

Automation

Enforce chrony settings through system role timesync.

Command Reference

firewall-cmd –add-service=ntp –permanent; systemctl restart chronyd

Escalation

Attach chrony logs and upstream network path checks.

Large VM suspend/resume gaps can require makestep tuning.

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.

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