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. - This instability affects components that implement leader election using the Kubernetes API, such as: - aws‑load‑balancer‑controller - karpenter - keda‑operator - ebs‑csi‑controller - efs‑csi‑controller
Mitigation
- Use Kubernetes API Priority and Fairness (FlowSchema and PriorityLevelConfiguration) to prioritize leader election traffic during high load. - Assign `workload‑high` priority to requests from critical components like the Karpenter controller. - Monitor etcd size and schedule regular defragmentation to reduce unplanned contention.