Ubuntu 18.04 LTS – Java app fails with too many open files

📖 ~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

Application crashes or degrades when file descriptor limits are exhausted.

Environment & Reproduction

Usually under high connection volume with low process or service ulimit values.

Root Cause Analysis

Open file/socket count exceeds configured hard or soft descriptor limits.

Quick Triage

Measure active descriptor count and compare against process limits.

Step-by-Step Diagnosis

Inspect service unit limits, PAM limits, and application leak patterns.

Solution – Primary Fix

Increase descriptor limits appropriately and remediate file/socket leak behavior.

Solution – Alternative Approaches

Reduce connection churn with pooling and tune worker concurrency to safe levels.

Verification & Acceptance Criteria

Descriptor usage remains below thresholds during peak load tests.

Rollback Plan

Restore previous limits if side effects appear in multi-tenant environments.

Prevention & Hardening

Track descriptor trends and alert before exhaustion thresholds are reached.

Related Errors & Cross-Refs

EMFILE too many open files and failed accept socket entries.

Related tutorial: View the step-by-step tutorial for Ubuntu 18.04 LTS.

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Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Linux file descriptor tuning and service-level ulimit management.