CentOS Stream 10 – Common Problem 054 – Diagnosis and Fix

📖 ~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

A systemd unit refuses to start with `Permission denied` while filesystem ACLs look correct.

Environment & Reproduction

Triggered after copying binaries or data files without preserving SELinux context.

Root Cause Analysis

Files lack the expected SELinux label so the confined domain cannot access them.

Quick Triage

Look for AVC denials with `ausearch -m AVC -ts recent` and `journalctl -t setroubleshoot`.

Step-by-Step Diagnosis

Identify the missing context and the file or port involved in the denial.

Solution – Primary Fix

Restore expected context with `restorecon -Rv ` or add a custom rule via `audit2allow`.

Solution – Alternative Approaches

Temporarily run the domain permissive with `semanage permissive -a ` while debugging.

Verification & Acceptance Criteria

Service starts successfully and no further AVCs appear for the affected operation.

Rollback Plan

Remove custom policy modules and re-relabel if behavior changes break unrelated services.

Prevention & Hardening

Always copy with `cp –preserve=all` or use `rsync -X` to preserve labels.

Related Errors & Cross-Refs

Often paired with port reassignments via `semanage port` and custom unit hardening.

Related tutorial: View the step-by-step tutorial for centos-stream-10.

View all centos-stream-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

SELinux troubleshooting documentation for CentOS Stream 10.