Ubuntu 22.04 LTS – netplan apply fails with YAML indentation errors

📖 ~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

Network changes fail and interfaces stay unconfigured after netplan apply.

Environment & Reproduction

Triggered by manual edits introducing tabs, bad indentation, or wrong keys.

Root Cause Analysis

Malformed YAML prevents netplan from generating backend network configuration.

Quick Triage

Identify file and line number from netplan parser errors.

Step-by-Step Diagnosis

Lint and inspect YAML structure before applying to active network.

Solution – Primary Fix

Correct YAML syntax, keep spaces-only indentation, then regenerate and apply.

Solution – Alternative Approaches

Restore last known-good netplan file if the change window is limited.

Verification & Acceptance Criteria

No parser errors and interfaces receive expected IP routes.

Rollback Plan

Revert to backup config and restart network renderer if required.

Prevention & Hardening

Use code review and template validation for all netplan updates.

Related Errors & Cross-Refs

Often coincides with interface not found and renderer mismatch errors.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu 22.04 netplan YAML schema and renderer documentation.