Time Drift In Virtual Machines Affecting Kerberos And TLS

📖 ~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

Kerberos tickets and TLS handshakes fail intermittently due to host clock skew.

Environment & Reproduction

Check `timedatectl`, `chronyc tracking`, and compare guest time with trusted reference.

Root Cause Analysis

Ensure virtualization guest tools and `chrony` packages are installed and current.

Quick Triage

Validate `systemctl status chronyd` and hypervisor time-sync interaction settings.

Step-by-Step Diagnosis

Inspect `journalctl -u chronyd` for source flaps and large step corrections.

Solution – Primary Fix

Record chrony config and hypervisor clock settings before policy changes.

Solution – Alternative Approaches

Ensure NTP traffic is allowed and DNS to time sources is stable through firewalld policies.

Verification & Acceptance Criteria

SELinux seldom blocks chrony defaults, but verify no denials on custom config paths.

Rollback Plan

Tune chrony sources, disable conflicting hypervisor sync where required, and restart chronyd.

Prevention & Hardening

Confirm offset remains low and auth-related errors no longer appear.

Related Errors & Cross-Refs

Use standardized VM time policies and monitor offset thresholds continuously.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Share chrony diagnostics, virtualization platform details, and drift timelines.