Grub Entry Boots Wrong Kernel by Default

📖 ~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

System repeatedly boots into an older or unintended kernel version.

Environment & Reproduction

Use grubby –default-kernel and grubby –info=ALL.

Root Cause Analysis

Verify installed kernels and identify expected production default.

Quick Triage

Default index not updated or old entry retained as first priority.

Step-by-Step Diagnosis

Set desired default with grubby –set-default /boot/vmlinuz-.

Solution – Primary Fix

Reboot and confirm with uname -r plus grubby –default-kernel.

Solution – Alternative Approaches

Confirm critical services start on target kernel after reboot.

Verification & Acceptance Criteria

Check NIC driver behavior and firewalld startup on new kernel.

Rollback Plan

SELinux policy should relabel normally; monitor for boot-time denials.

Prevention & Hardening

journalctl -b -1 helps compare previous boot behavior if needed.

Related Errors & Cross-Refs

Track kernel pinning policy in change management documents.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Select prior kernel from GRUB menu if regression appears.