CentOS Stream 9 – Common Problem 036 – 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

Critical service killed by oom-killer during memory pressure on CentOS Stream 9.

Environment & Reproduction

Hosts running JVM or in-memory caches without cgroup limits.

cat /etc/os-release
uname -r
rpm -qa | grep 

Root Cause Analysis

Workload exceeds physical memory and overcommit policy is permissive.

Quick Triage

Confirm package, network, SELinux and firewall state.

free -h
dmesg | grep -i oom
top -o %MEM

Step-by-Step Diagnosis

Drill into kernel/oom state and recent journal entries to isolate the failure.

journalctl -k -b | grep -i 'Out of memory'
systemctl show  | grep -i memory

Solution – Primary Fix

Apply the standard remediation for kernel/oom on CentOS Stream 9.

sudo systemctl edit   # set MemoryHigh and MemoryMax
sudo systemctl daemon-reload
sudo systemctl restart 

Solution – Alternative Approaches

Tune vm.overcommit_memory and add swap on dedicated SSD.

Verification & Acceptance Criteria

Validate the fix with positive functional checks before closing.

systemctl status 
free -h

Rollback Plan

Revert to the previous known-good configuration if the fix regresses.

sudo systemctl revert 

Prevention & Hardening

Codify the fix in configuration management and add monitoring.

Automate patch management and compliance across your fleet with our DevOps services.

Monitor cgroup memory.high events via Prometheus node exporter.

Related Errors & Cross-Refs

JVM heap mis-tuning and container memory limits.

Related tutorial: View the step-by-step tutorial for centos-stream-9.

View all centos-stream-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

systemd resource control documentation.