Ubuntu 20.04 LTS cloud-init Overwrites Netplan Configuration

📖 ~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

Manual network changes disappear after reboot, causing unpredictable addressing.

Environment & Reproduction

Ubuntu 20.04 LTS cloud image converted to long-lived server role.

Root Cause Analysis

cloud-init network module rewrites netplan from datasource metadata.

Quick Triage

Check whether cloud-init manages networking before editing netplan manually.

Step-by-Step Diagnosis

Review cloud-init configs and generated netplan files under /etc/netplan.

Solution – Primary Fix

Disable cloud-init network rendering and apply persistent custom netplan.

Solution – Alternative Approaches

Update datasource-provided network metadata to desired static settings.

Verification & Acceptance Criteria

Network config persists across reboot without cloud-init overwrites.

Rollback Plan

Re-enable cloud-init network module and restore previous generated files.

Prevention & Hardening

Decide a single source of truth for networking in server build templates.

Related Errors & Cross-Refs

Frequently appears alongside interface rename and DHCP fallback issues.

Related tutorial: View the step-by-step tutorial for Ubuntu 20.04 LTS.

View all Ubuntu 20.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

See cloud-init networking docs and netplan renderer guidance.