cdk-eks-karpenter

This construct configures the necessary dependencies and installs Karpenter
on an EKS cluster managed by AWS CDK.

Prerequisites

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If you have not used EC2 spot in your AWS account before, follow the instructions
here to create
the service linked role in your account allowing Karpenter to provision EC2 Spot Capacity.

Using

In your CDK project, initialize a new Karpenter construct for your EKS cluster, like this:

``typescript
const cluster = new Cluster(this, 'testCluster', {
vpc: vpc,
role: clusterRole,
version: KubernetesVersion.V1_27,
defaultCapacity: 1
});

const karpenter = new Karpenter(this, 'Karpenter', {
cluster: cluster,
namespace: "kube-system"
});
`

This will install and configure Karpenter in your cluster. To have Karpenter do something useful, you
also need to create an EC2NodeClass and an
NodePool, for a more complete example, see
test/integ.karpenter.ts.

Known issues

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As of aws/karpenter#1145 the Karpenter Helm chart is
refactored to specify clusterEndpoint and clusterName on the root level of the chart values, previously
these values was specified under the key controller.

Testing

This construct adds a custom task to projen, so you can test a full deployment
of an EKS cluster with Karpenter installed as specified in test/integ.karpenter.ts by running the
following:

`sh
export CDK_DEFAULT_REGION=
export CDK_DEFAULT_ACCOUNT=
npx projen test:deploy
`

As the above will create a cluster without EC2 capacity, with CoreDNS and Karpenter running as Fargate
pods, you can test out the functionality of Karpenter by deploying an inflation deployment, which will
spin up a number of pods that will trigger Karpenter creation of worker nodes:

`sh
kubectl apply -f test/inflater-deployment.yml
`

You can clean things up by deleting the deployment and the CDK test stack:

`sh
kubectl delete -f test/inflater-deployment.yml
npx projen test:destroy
``

FAQ

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1. Ensure you have the appropriate linked role available in your account, for more details,
see the karpenter documentation