Ubuntu 16.04 LTS PHP 7.0-FPM not running

📖 ~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

Web requests return 502 or PHP pages are not processed.

Environment & Reproduction

Ubuntu 16.04 with Apache or Nginx proxying to php-fpm.

Root Cause Analysis

Broken pool configuration or socket permission mismatch causes startup failure.

Quick Triage

Check php-fpm service state and web server upstream errors.

Step-by-Step Diagnosis

Validate php-fpm config syntax and socket path consistency.

Solution – Primary Fix

Fix pool settings, permissions, and restart services in order.

Solution – Alternative Approaches

Switch to TCP upstream temporarily for easier debugging.

Verification & Acceptance Criteria

Dynamic PHP pages load successfully without gateway errors.

Rollback Plan

Revert php-fpm pool and web server upstream changes.

Prevention & Hardening

Add config linting to deployment pipeline for PHP stacks.

Related Errors & Cross-Refs

Compare with Apache module mismatch and process OOM failures.

Related tutorial: View the step-by-step tutorial for Ubuntu 16.04 LTS.

View all Ubuntu 16.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

PHP-FPM configuration references and Ubuntu package docs.