Affected versions: 26.04

πŸ“– ~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

TLS connections fail, logs have incorrect timestamps, and scheduled jobs run at wrong times due to clock drift.

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Environment & Reproduction

Common in virtualized hosts, disconnected networks, or systems migrated across time zones.

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Root Cause Analysis

NTP service is disabled, blocked by firewall, or pointed to unreachable servers.

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Quick Triage

Run timedatectl and systemctl status systemd-timesyncd to verify synchronization state quickly.

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Step-by-Step Diagnosis

Check NTP peers and recent sync attempts with journalctl -u systemd-timesyncd -n 100.

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Solution – Primary Fix

Enable service using sudo systemctl enable –now systemd-timesyncd, set valid NTP servers in /etc/systemd/timesyncd.conf, then restart service.

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Solution – Alternative Approaches

Use chrony package for advanced environments requiring multiple peers and stricter drift controls.

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Verification & Acceptance Criteria

timedatectl shows ‘System clock synchronized: yes’ and TLS services stop reporting certificate time mismatch.

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Rollback Plan

Revert timesyncd configuration changes and disable custom NTP entries if they create instability.

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Prevention & Hardening

Use internal NTP sources for servers and monitor time offset in routine health checks.

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Related errors include apt TLS failures and Kerberos skew issues due to incorrect system time.

Related tutorial: View the step-by-step tutorial for Ubuntu 26.04 LTS.

View all Ubuntu 26.04 LTS tutorials on the Tutorials Hub β†’

Browse all common problems & solutions on the Tutorials Hub.

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References & Further Reading

timedatectl man page, systemd-timesyncd docs, and Ubuntu server time synchronization guidance.

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Need Expert Help?

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