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title: "Getting Started with Karpenter" linkTitle: "Getting Started with Karpenter" weight: 10 description: > Set up a cluster and add Karpenter

Karpenter automatically provisions new nodes in response to unschedulable pods. Karpenter does this by observing events within the Kubernetes cluster, and then sending commands to the underlying cloud provider.

This guide shows how to get started with Karpenter by creating a Kubernetes cluster and installing Karpenter. To use Karpenter, you must be running a supported Kubernetes cluster on a supported cloud provider. Currently, only EKS on AWS is supported.

Create a cluster and add Karpenter

This guide uses eksctl to create the cluster. It should take less than 1 hour to complete, and cost less than $0.25. Follow the clean-up instructions to reduce any charges.

1. Install utilities

Karpenter is installed in clusters with a Helm chart.

Karpenter requires cloud provider permissions to provision nodes, for AWS IAM Roles for Service Accounts (IRSA) should be used. IRSA permits Karpenter (within the cluster) to make privileged requests to AWS (as the cloud provider) via a ServiceAccount.

Install these tools before proceeding:

  1. AWS CLI
  2. kubectl - the Kubernetes CLI
  3. eksctl - the CLI for AWS EKS
  4. helm - the package manager for Kubernetes

Configure the AWS CLI with a user that has sufficient privileges to create an EKS cluster. Verify that the CLI can authenticate properly by running aws sts get-caller-identity.

2. Set environment variables

After setting up the tools, set the Karpenter and Kubernetes version:

export KARPENTER_VERSION=v0.32.0
export K8S_VERSION={{< param "latest_k8s_version" >}}

Then set the following environment variable:

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step01-config.sh" language="bash"%}}

{{% alert title="Warning" color="warning" %}} If you open a new shell to run steps in this procedure, you need to set some or all of the environment variables again. To remind yourself of these values, type:

echo $KARPENTER_VERSION $K8S_VERSION $CLUSTER_NAME $AWS_DEFAULT_REGION $AWS_ACCOUNT_ID $TEMPOUT

{{% /alert %}}

3. Create a Cluster

Create a basic cluster with eksctl. The following cluster configuration will:

  • Use CloudFormation to set up the infrastructure needed by the EKS cluster.
  • Create a Kubernetes service account and AWS IAM Role, and associate them using IRSA to let Karpenter launch instances.
  • Add the Karpenter node role to the aws-auth configmap to allow nodes to connect.
  • Use AWS EKS managed node groups for the kube-system and karpenter namespaces. Uncomment fargateProfiles settings (and comment out managedNodeGroups settings) to use Fargate for both namespaces instead.
  • Set KARPENTER_IAM_ROLE_ARN variables.
  • Create a role to allow spot instances.
  • Run helm to install karpenter

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step02-create-cluster.sh" language="bash"%}}

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step06-add-spot-role.sh" language="bash"%}}

{{% alert title="Windows Support Notice" color="warning" %}} In order to run Windows workloads, Windows support should be enabled in your EKS Cluster. See Enabling Windows support to learn more. {{% /alert %}}

4. Install Karpenter

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step08-apply-helm-chart.sh" language="bash"%}}

{{% alert title="Warning" color="warning" %}} Karpenter creates a mapping between CloudProvider machines and CustomResources in the cluster for capacity tracking. To ensure this mapping is consistent, Karpenter utilizes the following tag keys:

  • karpenter.sh/managed-by
  • karpenter.sh/nodepool
  • kubernetes.io/cluster/${CLUSTER_NAME}

Because Karpenter takes this dependency, any user that has the ability to Create/Delete these tags on CloudProvider machines will have the ability to orchestrate Karpenter to Create/Delete CloudProvider machines as a side effect. We recommend that you enforce tag-based IAM policies on these tags against any EC2 instance resource (i-*) for any users that might have CreateTags/DeleteTags permissions but should not have RunInstances/TerminateInstances permissions. {{% /alert %}}

5. Create NodePool

A single Karpenter NodePool is capable of handling many different pod shapes. Karpenter makes scheduling and provisioning decisions based on pod attributes such as labels and affinity. In other words, Karpenter eliminates the need to manage many different node groups.

Create a default NodePool using the command below. This NodePool uses securityGroupSelectorTerms and subnetSelectorTerms to discover resources used to launch nodes. We applied the tag karpenter.sh/discovery in the eksctl command above. Depending on how these resources are shared between clusters, you may need to use different tagging schemes.

The consolidationPolicy set to WhenUnderutilized in the disruption block configures Karpenter to reduce cluster cost by removing and replacing nodes. As a result, consolidation will terminate any empty nodes on the cluster. This behavior can be disabled by setting consolidateAfter to Never, telling Karpenter that it should never consolidate nodes. Review the [NodePool API docs]({{<ref "../../concepts/nodepools" >}}) for more information.

Note: This NodePool will create capacity as long as the sum of all created capacity is less than the specified limit.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step12-add-nodepool.sh" language="bash"%}}

Karpenter is now active and ready to begin provisioning nodes.

First Use

Create some pods using a deployment and watch Karpenter provision nodes in response.

Scale up deployment

This deployment uses the pause image and starts with zero replicas.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step13-automatic-node-provisioning.sh" language="bash"%}}

Scale down deployment

Now, delete the deployment. After a short amount of time, Karpenter should terminate the empty nodes due to consolidation.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step14-deprovisioning.sh" language="bash"%}}

Add optional monitoring with Grafana

This section describes optional ways to configure Karpenter to enhance its capabilities. In particular, the following commands deploy a Prometheus and Grafana stack that is suitable for this guide but does not include persistent storage or other configurations that would be necessary for monitoring a production deployment of Karpenter. This deployment includes two Karpenter dashboards that are automatically onboarded to Grafana. They provide a variety of visualization examples on Karpenter metrics.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step09-add-prometheus-grafana.sh" language="bash"%}}

The Grafana instance may be accessed using port forwarding.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step10-add-grafana-port-forward.sh" language="bash"%}}

The new stack has only one user, admin, and the password is stored in a secret. The following command will retrieve the password.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step11-grafana-get-password.sh" language="bash"%}}

Cleanup

Delete Karpenter nodes manually

If you delete a node with kubectl, Karpenter will gracefully cordon, drain, and shutdown the corresponding instance. Under the hood, Karpenter adds a finalizer to the node object, which blocks deletion until all pods are drained and the instance is terminated. Keep in mind, this only works for nodes provisioned by Karpenter.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step15-delete-node.sh" language="bash"%}}

Delete the cluster

To avoid additional charges, remove the demo infrastructure from your AWS account.

{{% script file="./content/en/{VERSION}/getting-started/getting-started-with-karpenter/scripts/step16-cleanup.sh" language="bash"%}}