Ubuntu 24.04 LTS Cloud-Init Overwrites Netplan on Reboot

📖 ~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 settings vanish after reboot, causing intermittent outages and changed IP assignments.

Environment & Reproduction

Typical on cloud images promoted to long-running Ubuntu 24.04 LTS server workloads.

Root Cause Analysis

cloud-init networking module rewrites netplan from datasource metadata on each boot.

Quick Triage

Verify whether cloud-init still controls network rendering before editing netplan files again.

cloud-init status --long; ls /etc/cloud/cloud.cfg.d

Step-by-Step Diagnosis

Inspect generated netplan files and cloud-init logs to confirm ownership of configuration writes.

grep -R network /etc/cloud/cloud.cfg* /etc/cloud/cloud.cfg.d/*; sudo journalctl -u cloud-init --since '1 day ago'

Solution – Primary Fix

Disable cloud-init network config and maintain authoritative netplan YAML managed by operations.

printf 'network: {config: disabled}
' | sudo tee /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg && sudo netplan apply

Solution – Alternative Approaches

Retain cloud-init but provide stable user-data network definitions per instance profile.

Verification & Acceptance Criteria

Reboot preserves interface config and no new cloud-init netplan file overrides appear.

Rollback Plan

Remove disable file and rerun cloud-init clean if managed cloud networking is required.

Prevention & Hardening

Standardize image post-provisioning policy that defines a single source of network truth.

Related Errors & Cross-Refs

Cross-reference DHCP lease churn and netplan renderer mismatch scenarios.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

cloud-init networking docs and Ubuntu cloud image guidance.