Amazon EKS · 12 August 2026

Amazon EKS control plane parameters¶

Amazon EKS now lets you configure four parameters on kube-apiserver, kube-scheduler, and kube-controller-manager through the EKS API. Existing clusters keep their previous behaviour until you explicitly call UpdateClusterConfig.

See the parameters Existing clusters

At a glance¶

Component	Parameter	Default	Range
kube-scheduler	Scoring strategy	`LeastAllocated`	`LeastAllocated` · `MostAllocated`
kube-controller-manager	HPA sync period	`15s`	`10s`–`15s` (Provisioned only)
kube-apiserver	Event TTL	`60m`	`10m`–`60m`
kube-apiserver	NodePort range	`30000`–`32767`	`10260`–`32767`

Requires Kubernetes 1.31 or later. Updates apply with a rolling control plane update and affect only new scheduling decisions and new events.

Requirements¶

Requirement	Minimum
Cluster Kubernetes version	1.31
AWS CLI (only if you use the CLI, not the console)	2.36.21 — first release with `--kube-scheduler-config` / `--kube-api-server-config` / `--kube-controller-manager-config`
Provisioned Control Plane	Only if you set HPA sync period below 15s

The console does not depend on the CLI version. Upgrade AWS CLI v2 with the bundled installer (./aws/install --update). Do not use pip install awscli for v2.

Why this matters¶

Before Spread was the only option

The EKS scheduler used LeastAllocated. Bin-packing required running a second scheduler and annotating every pod with spec.schedulerName.

roadmap #1468 Existing clusters No behaviour change on launch day

DescribeCluster returns the new fields as null until you Save. Scheduling does not change on launch day.

new binds only Interaction Scheduler ≠ provisioner

MostAllocated places pods on existing nodes. Karpenter or Auto Mode decides whether nodes should exist at all.

two layers

What this does not do¶

Move running pods. Scoring applies to new scheduling decisions. Pods already bound to a node stay there.
Replace a full KubeSchedulerConfiguration. As of August 2026, only the four fields above are supported. RequestedToCapacityRatio and arbitrary flags are still unavailable.
Apply automatically. A cluster created before 12 August 2026 keeps its defaults until you explicitly update it.

Contents¶

1. Before this feature Custom schedulers, GKE comparison, and what was unsupported 2. Existing clusters API response versus scheduler behaviour; running pods stay bound 3. Parameters Defaults, validated ranges, CLI examples, and operational limits 4. Scheduler and provisioner MostAllocated places pods; it does not create or delete nodes

Relation to AWS documentation

This site adds context to the What's New announcement and the Amazon EKS user guide. The AWS walkthrough shows how to enable MostAllocated. These pages describe what that change does and does not do.