Skip to content

Karpenter custom Nodepool as default

Configure custom nodepool as your primary

karpenter EKS Auto mode comes with pre-installed Karpenter Autoscaler, default NodeClass and a default Nodepool. Default Nodepool is configured to provision AMD architecture, on-demand servers. While this makes it easy to get started, many organizations have complex requirements like deploying specific CPU or GPU instances, or making use of SPOT or Reserved instances to save cost.

Custom NodePool as default

The default NodePool provided by AWS cannot be modified, however Karpenter allows you to order your NodePools using the spec.weight field so that the Karpenter scheduler will attempt to schedule one NodePool before another. This field can be used to define custom NodePool that will have higher priority than default NodePool. ec2 Spot instance

Nodepool with Spot and on-demanad instances

In this example, I am creating a custom Nodepool that has priority over default NodePool. This NodePool will provision SPOT and On-Demanad instances. Karpenter aims to provision most cost effective instances, which are often Spot instances. You can achieve split of On-Demanad vsSpot instances using On-Demand/Spot Ratio Split or by provisioning 2 nodepools with same weight.

primary-nodepool.yaml 

apiVersion: karpenter.sh/v1
kind: NodePool
metadata:
  name: primary-nodepool
spec:
  weight: 50
  template:
    spec:
      expireAfter: 336h
      nodeClassRef:
        group: eks.amazonaws.com
        kind: NodeClass
        name: default
      requirements:
      - key: karpenter.sh/capacity-type
        operator: In
        values: ["spot","on-demand"]
      - key: eks.amazonaws.com/instance-category
        operator: In
        values: ["c","m","r"]
      - key: eks.amazonaws.com/instance-generation
        operator: Gt
        values: ["5"]
      - key: kubernetes.io/arch
        operator: In
        values:
        - amd64
      - key: kubernetes.io/os
        operator: In
        values:
        - linux
      terminationGracePeriod: 24h0m0s
Since primary-nodepool has higher weight, this nodepool will be selected first.

karpenter

If you have purchased a Savings Plan or Reserved Instances, this methodcan be used to make Karpenter to prioritize this reserved capacity ahead of other instance types.