Ubuntu 22.04 LTS – MySQL fails to start because AppArmor blocks data path – Fix & Prevention

📖 ~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

Database service remains down after datadir relocation, breaking application startup and transactions.

Environment & Reproduction

Seen when MySQL datadir is moved without updating AppArmor rules.

Root Cause Analysis

AppArmor profile for mysqld does not permit access to new storage path, so startup aborts.

Quick Triage

Check kernel audit denials and mysql error logs for AppArmor path violations.

Step-by-Step Diagnosis

Confirm datadir path and required file access patterns in mysqld profile.

Solution – Primary Fix

Add correct datadir rules to AppArmor local override and reload profile before restarting MySQL.

Solution – Alternative Approaches

Return datadir to default location if profile changes are restricted by policy.

Verification & Acceptance Criteria

MySQL starts normally and no new AppArmor denials occur for mysqld process.

Rollback Plan

Remove custom profile lines and revert datadir setting if application behavior regresses.

Prevention & Hardening

Include AppArmor profile updates in any database storage migration procedure.

Related Errors & Cross-Refs

Often appears with file ownership issues and SELinux assumptions imported from non-Ubuntu guides.

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 AppArmor and MySQL deployment documentation.