Introduction

This action terminates a percentage of the EC2 instances backing an EKS managed node group.

Instances are terminated through the node group's underlying Auto Scaling group, which replaces them automatically within minutes.

Use Cases

• Validate that pods reschedule onto healthy nodes when a fraction of the node group disappears.
• Verify Pod Disruption Budgets, taints/tolerations, and topology spread constraints under node loss.
• Measure cold-start cost: image pull, CSI volume re-attach, init containers on freshly launched nodes.

Rollback

This attack does not support rollback.

The terminated instances cannot be brought back; the Auto Scaling group launches fresh replacements. Cancellation is a no-op.

Parameters

Parameter	Description	Default
Percentage of instances to terminate	Percentage (1-100) of InService instances to terminate. Rounded up to at least one host.	33