Ubuntu 18.04 LTS – memory pressure triggers OOM kills and random restarts – 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

Critical services are killed under load, causing outages and instability.

Environment & Reproduction

Ubuntu 20.04 VM with constrained RAM and bursty workloads.

Root Cause Analysis

Memory overcommit and absent guardrails trigger kernel OOM decisions.

Quick Triage

Inspect dmesg for OOM traces and identify repeatedly killed processes.

Step-by-Step Diagnosis

Profile resident memory growth and cgroup usage during peak traffic.

Solution – Primary Fix

Set resource limits, optimize memory-heavy services, and tune swap strategy.

Solution – Alternative Approaches

Scale vertically or distribute workload across additional nodes.

Verification & Acceptance Criteria

No OOM kills occur under representative stress and latency remains stable.

Rollback Plan

Revert tuning changes and restore previous service memory settings.

Prevention & Hardening

Use alerts for memory saturation and enforce per-service memory quotas.

Related Errors & Cross-Refs

Swap thrashing and high iowait often precede OOM conditions.

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

View all Ubuntu 18.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Linux memory management and OOM tuning on Ubuntu.