CRE-2025-0061
Karpenter Stability Issues on EKS During Leader ElectionMediumImpact: 7/10Mitigation: 4/10
CRE-2025-0061View on GitHub
Description
- EKS may be able to handle steady, predictable scale, but struggles during large‑scale auto scaling events when many workloads and nodes are spinning up or down simultaneously.\n- This instability affects components that implement leader election using the Kubernetes API, such as:\n - aws‑load‑balancer‑controller\n - karpenter\n - keda‑operator\n - ebs‑csi‑controller\n - efs‑csi‑controller\n
Mitigation
- Use Kubernetes API Priority and Fairness (FlowSchema and PriorityLevelConfiguration) to prioritize leader election traffic during high load.\n- Assign `workload‑high` priority to requests from critical components like the Karpenter controller.\n- Monitor etcd size and schedule regular defragmentation to reduce unplanned contention.\n