CentOS Stream 10 – Common Problem 198 – 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

After a crash there is no /var/crash//vmcore file.

Environment & Reproduction

Insufficient crashkernel memory or wrong target path.

kdumpctl status
cat /etc/kdump.conf

Root Cause Analysis

kdump kernel cannot boot or cannot reach the configured target.

Quick Triage

Verify reserved memory and kdump service state.

cat /sys/kernel/kexec_crash_size
systemctl status kdump

Step-by-Step Diagnosis

Test kdump by triggering a sysrq crash on a non-prod host.

echo 1 > /proc/sys/kernel/sysrq && echo c > /proc/sysrq-trigger

Solution – Primary Fix

Increase crashkernel and rebuild initrd.

grubby --update-kernel=ALL --args=crashkernel=512M
kdumpctl restart

Solution – Alternative Approaches

Ship vmcore to a remote NFS or SSH target.

echo 'ssh user@dumphost' >> /etc/kdump.conf
kdumpctl propagate

Verification & Acceptance Criteria

After a triggered crash, /var/crash contains a fresh vmcore.

ls -ltrh /var/crash | tail

Rollback Plan

Revert grub args.

grubby --update-kernel=ALL --remove-args=crashkernel

Prevention & Hardening

Test kdump quarterly.

echo c > /proc/sysrq-trigger # scheduled in non-prod

Related Errors & Cross-Refs

kdump fails, kexec error, no vmcore generated.

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

kdump docs, makedumpfile reference.