📖 ~1 min read
Table of contents
Symptom & Impact
System time drifts or resets, causing certificate validation failures and inconsistent scheduled task execution.
Environment & Reproduction
Timestamps jump after reboot or resume, and logs show events out of sequence across services.
Root Cause Analysis
Disabled NTP sync, incorrect timezone settings, RTC mismatch, or failing CMOS battery may be involved.
Quick Triage
Verify timezone configuration and check whether time synchronization service is active.
Step-by-Step Diagnosis
Inspect timedate status, NTP reachability, and RTC drift behavior over a controlled observation window.
Solution – Primary Fix
Enable network time synchronization, correct timezone and RTC mode, and restart time services.
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Solution – Alternative Approaches
Switch to an internal NTP source or replace failing hardware clock battery where drift persists.
Verification & Acceptance Criteria
System time remains accurate across reboot cycles and certificate-dependent services operate normally.
Rollback Plan
Revert custom time daemon settings and restore default sync configuration if side effects appear.
Prevention & Hardening
Monitor time offset metrics and enforce trusted time sources across all managed hosts.
Related Errors & Cross-Refs
Associated with TLS handshake failures, Kerberos clock skew, and cron schedule drift.
Related tutorial: View the step-by-step tutorial for Ubuntu 16.04 LTS.
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References & Further Reading
Use Ubuntu time synchronization documentation and NTP service administration references.
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