Ubuntu 22.04 LTS – kubelet fails because swap is enabled – 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

kubelet fails to start, preventing node registration and workload scheduling.

Environment & Reproduction

Seen on Ubuntu 22.04 nodes where swap is enabled by default or re-enabled after reboot.

Root Cause Analysis

Kubernetes node configuration requires swap to be disabled for stable kubelet operation.

Quick Triage

Check active swap devices and kubelet journal for startup validation errors.

Step-by-Step Diagnosis

Confirm fstab entries and kubelet flags to ensure swap policy alignment.

Solution – Primary Fix

Disable swap immediately and persist configuration so it stays disabled after reboot.

Solution – Alternative Approaches

If swap must remain for policy reasons, use controlled kubelet configuration with explicit risk acceptance.

Verification & Acceptance Criteria

kubelet is active, swap is disabled, and node reports Ready status.

Rollback Plan

Restore prior fstab entries only if reverting Kubernetes deployment on the host.

Prevention & Hardening

Enforce swap disablement in node bootstrap automation and compliance checks.

Related Errors & Cross-Refs

Often paired with container runtime misconfiguration and cgroup driver mismatches.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Kubernetes node prerequisites and Ubuntu 22.04 LTS operational practices for kubelet stability.