🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026

📖 ~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 because cloud-init regenerates config unexpectedly.

Environment & Reproduction

Ubuntu 20.04 cloud instance with cloud-init enabled and netplan files under ‘/etc/netplan’.

Root Cause Analysis

cloud-init datasource policy rewrites network YAML during boot, overriding local edits.

Quick Triage

Check cloud-init status, inspect ‘/etc/cloud/cloud.cfg.d’, and identify generated netplan file ownership.

Step-by-Step Diagnosis

Review cloud-init logs, datasource metadata, and boot sequence to locate config regeneration point.

Illustrative mockup for ubuntu-20-04-lts — ubuntu2004-cp25-cloudinit-network-diagnose.webp
Diagnosing cloud-init network reconfiguration surprises — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Disable cloud-init network config for static hosts and maintain authoritative netplan file manually.

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Illustrative mockup for ubuntu-20-04-lts — ubuntu2004-cp25-cloudinit-network-fix.webp
Pinning stable network config against cloud-init overrides — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Define desired network in cloud-init user-data so regeneration remains intentional and versioned.

Verification & Acceptance Criteria

Network settings persist across multiple reboots and instance metadata refresh events.

Rollback Plan

Re-enable previous cloud-init network behavior and restore generated file baseline if required.

Prevention & Hardening

Document ownership of network config and avoid direct edits to auto-generated cloud-init files.

netplan config replaced on boot, lost static IP, and cloud-init stage networking warnings.

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

cloud-init network configuration docs, Ubuntu cloud images guide, and netplan integration references.

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