EKS Cluster Autoscaling Not Configured
1
1
medium
What does ZopNight detect here?
EKS clusters whose managed node groups all pin MinSize equal to MaxSize have no visible autoscaling and get a $0 advisory. Karpenter or EKS Auto Mode hosted on a fixed-size node group looks identical, so operators can set autoscaling_managed_externally=true to suppress the finding; Fargate-only clusters are never stamped.
Signal and threshold
| Field | Value |
|---|---|
| Rule IDs | RC-060 |
| Category | compliance |
| Severity | medium |
| Metric | none — pure configuration read |
| Source | eks_autoscaling.go |
Where it applies
Node group scaling config and its blind spot
- Metadata: autoscaling_enabled (bool): the EKS discoverer’s annotateAutoscalingEnabled (eks.go) stamps this per cluster: true when any managed node group’s ScalingConfig has MinSize != MaxSize. Only stamped when the cluster has at least one managed node group (Fargate-only clusters leave the key absent).
- Metadata (optional operator override): autoscaling_managed_externally (bool), set explicitly to true to suppress the rule for a cluster confirmed to autoscale via a controller the discoverer cannot see (Karpenter, EKS Auto Mode) hosted on a fixed-size managed node group. the discoverer’s only signal is managed node group ScalingConfig. A cluster running Karpenter or EKS Auto Mode for elastic scaling, with the controller hosted on a small fixed-size managed node group (MinSize == MaxSize, the AWS-documented topology), is indistinguishable from a cluster with no autoscaling at all and will fire until either the autoscaling_managed_externally override is set on the resource or the discoverer gains a Karpenter/EKS Auto Mode presence signal (not yet implemented).
Why no dollar figure is attached
fixed estimate: $0/mo
Picking an autoscaler, or declaring one
- Choose an autoscaling solution: Cluster Autoscaler, Karpenter, or EKS Auto Mode
- For Cluster Autoscaler: deploy via Helm and configure node group min/max sizes (set MinSize != MaxSize)
- For Karpenter: install the controller and create NodePool + EC2NodeClass manifests
- For EKS Auto Mode: enable in cluster settings (API: UpdateClusterConfig)
- If autoscaling is already handled by Karpenter/EKS Auto Mode on a fixed-size managed node group, set autoscaling_managed_externally=true on the resource to suppress this rule