Amazon EKS Construct Library

--- ![cfn-resources: Stable](https://img.shields.io/badge/cfn--resources-stable-success.svg?style=for-the-badge) > All classes with the `Cfn` prefix in this module ([CFN Resources](https://docs.aws.amazon.com/cdk/latest/guide/constructs.html#constructs_lib)) are always stable and safe to use. ![cdk-constructs: Experimental](https://img.shields.io/badge/cdk--constructs-experimental-important.svg?style=for-the-badge) > The APIs of higher level constructs in this module are experimental and under active development. They are subject to non-backward compatible changes or removal in any future version. These are not subject to the [Semantic Versioning](https://semver.org/) model and breaking changes will be announced in the release notes. This means that while you may use them, you may need to update your source code when upgrading to a newer version of this package. ---

This construct library allows you to define Amazon Elastic Container Service for Kubernetes (EKS) clusters programmatically. This library also supports programmatically defining Kubernetes resource manifests within EKS clusters.

This example defines an Amazon EKS cluster with the following configuration:

  • Managed nodegroup with 2x m5.large instances (this instance type suits most common use-cases, and is good value for money)

  • Dedicated VPC with default configuration (see ec2.Vpc)

  • A Kubernetes pod with a container based on the paulbouwer/hello-kubernetes image.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster = eks.Cluster(self, "hello-eks")

cluster.add_resource("mypod",
    api_version="v1",
    kind="Pod",
    metadata={"name": "mypod"},
    spec={
        "containers": [{
            "name": "hello",
            "image": "paulbouwer/hello-kubernetes:1.5",
            "ports": [{"container_port": 8080}]
        }
        ]
    }
)

Capacity

By default, eks.Cluster is created with a managed nodegroup with x2 m5.large instances.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
eks.Cluster(self, "cluster-two-m5-large")

To use the traditional self-managed Amazon EC2 instances instead, set defaultCapacityType to DefaultCapacityType.EC2

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster = eks.Cluster(self, "cluster-self-managed-ec2",
    default_capacity_type=eks.DefaultCapacityType.EC2
)

The quantity and instance type for the default capacity can be specified through the defaultCapacity and defaultCapacityInstance props:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
eks.Cluster(self, "cluster",
    default_capacity=10,
    default_capacity_instance=ec2.InstanceType("m2.xlarge")
)

To disable the default capacity, simply set defaultCapacity to 0:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
eks.Cluster(self, "cluster-with-no-capacity", default_capacity=0)

The cluster.defaultCapacity property will reference the AutoScalingGroup resource for the default capacity. It will be undefined if defaultCapacity is set to 0 or defaultCapacityType is either NODEGROUP or undefined.

And the cluster.defaultNodegroup property will reference the Nodegroup resource for the default capacity. It will be undefined if defaultCapacity is set to 0 or defaultCapacityType is EC2.

You can add AutoScalingGroup resource as customized capacity through cluster.addCapacity() or cluster.addAutoScalingGroup():

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster.add_capacity("frontend-nodes",
    instance_type=ec2.InstanceType("t2.medium"),
    min_capacity=3,
    vpc_subnets={"subnet_type": ec2.SubnetType.PUBLIC}
)

Managed Node Groups

Amazon EKS managed node groups automate the provisioning and lifecycle management of nodes (Amazon EC2 instances) for Amazon EKS Kubernetes clusters. By default, eks.Nodegroup create a nodegroup with x2 t3.medium instances.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
eks.Nodegroup(stack, "nodegroup", cluster=cluster)

You can add customized node group through cluster.addNodegroup():

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster.add_nodegroup("nodegroup",
    instance_type=ec2.InstanceType("m5.large"),
    min_size=4
)

Fargate

AWS Fargate is a technology that provides on-demand, right-sized compute capacity for containers. With AWS Fargate, you no longer have to provision, configure, or scale groups of virtual machines to run containers. This removes the need to choose server types, decide when to scale your node groups, or optimize cluster packing.

You can control which pods start on Fargate and how they run with Fargate Profiles, which are defined as part of your Amazon EKS cluster.

See Fargate Considerations in the AWS EKS User Guide.

You can add Fargate Profiles to any EKS cluster defined in your CDK app through the addFargateProfile() method. The following example adds a profile that will match all pods from the “default” namespace:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster.add_fargate_profile("MyProfile",
    selectors=[{"namespace": "default"}]
)

To create an EKS cluster that only uses Fargate capacity, you can use FargateCluster.

The following code defines an Amazon EKS cluster without EC2 capacity and a default Fargate Profile that matches all pods from the “kube-system” and “default” namespaces. It is also configured to run CoreDNS on Fargate through the coreDnsComputeType cluster option.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster = eks.FargateCluster(self, "MyCluster")

# apply k8s resources on this cluster
cluster.add_resource(...)

NOTE: Classic Load Balancers and Network Load Balancers are not supported on pods running on Fargate. For ingress, we recommend that you use the ALB Ingress Controller on Amazon EKS (minimum version v1.1.4).

Spot Capacity

If spotPrice is specified, the capacity will be purchased from spot instances:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster.add_capacity("spot",
    spot_price="0.1094",
    instance_type=ec2.InstanceType("t3.large"),
    max_capacity=10
)

Spot instance nodes will be labeled with lifecycle=Ec2Spot and tainted with PreferNoSchedule.

The AWS Node Termination Handler DaemonSet will be installed from ` Amazon EKS Helm chart repository <https://github.com/aws/eks-charts/tree/master/stable/aws-node-termination-handler>`_ on these nodes. The termination handler ensures that the Kubernetes control plane responds appropriately to events that can cause your EC2 instance to become unavailable, such as EC2 maintenance events and EC2 Spot interruptions and helps gracefully stop all pods running on spot nodes that are about to be terminated.

Bootstrapping

When adding capacity, you can specify options for /etc/eks/boostrap.sh which is responsible for associating the node to the EKS cluster. For example, you can use kubeletExtraArgs to add custom node labels or taints.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
# up to ten spot instances
cluster.add_capacity("spot",
    instance_type=ec2.InstanceType("t3.large"),
    min_capacity=2,
    bootstrap_options={
        "kubelet_extra_args": "--node-labels foo=bar,goo=far",
        "aws_api_retry_attempts": 5
    }
)

To disable bootstrapping altogether (i.e. to fully customize user-data), set bootstrapEnabled to false when you add the capacity.

Masters Role

The Amazon EKS construct library allows you to specify an IAM role that will be granted system:masters privileges on your cluster.

Without specifying a mastersRole, you will not be able to interact manually with the cluster.

The following example defines an IAM role that can be assumed by all users in the account and shows how to use the mastersRole property to map this role to the Kubernetes system:masters group:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
# first define the role
cluster_admin = iam.Role(self, "AdminRole",
    assumed_by=iam.AccountRootPrincipal()
)

# now define the cluster and map role to "masters" RBAC group
eks.Cluster(self, "Cluster",
    masters_role=cluster_admin
)

When you cdk deploy this CDK app, you will notice that an output will be printed with the update-kubeconfig command.

Something like this:

Outputs:
eks-integ-defaults.ClusterConfigCommand43AAE40F = aws eks update-kubeconfig --name cluster-ba7c166b-c4f3-421c-bf8a-6812e4036a33 --role-arn arn:aws:iam::112233445566:role/eks-integ-defaults-Role1ABCC5F0-1EFK2W5ZJD98Y

Copy & paste the “aws eks update-kubeconfig ...” command to your shell in order to connect to your EKS cluster with the “masters” role.

Now, given AWS CLI is configured to use AWS credentials for a user that is trusted by the masters role, you should be able to interact with your cluster through kubectl (the above example will trust all users in the account).

For example:

$ aws eks update-kubeconfig --name cluster-ba7c166b-c4f3-421c-bf8a-6812e4036a33 --role-arn arn:aws:iam::112233445566:role/eks-integ-defaults-Role1ABCC5F0-1EFK2W5ZJD98Y
Added new context arn:aws:eks:eu-west-2:112233445566:cluster/cluster-ba7c166b-c4f3-421c-bf8a-6812e4036a33 to /Users/boom/.kube/config

$ kubectl get nodes # list all nodes
NAME                                         STATUS   ROLES    AGE   VERSION
ip-10-0-147-66.eu-west-2.compute.internal    Ready    <none>   21m   v1.13.7-eks-c57ff8
ip-10-0-169-151.eu-west-2.compute.internal   Ready    <none>   21m   v1.13.7-eks-c57ff8

$ kubectl get all -n kube-system
NAME                           READY   STATUS    RESTARTS   AGE
pod/aws-node-fpmwv             1/1     Running   0          21m
pod/aws-node-m9htf             1/1     Running   0          21m
pod/coredns-5cb4fb54c7-q222j   1/1     Running   0          23m
pod/coredns-5cb4fb54c7-v9nxx   1/1     Running   0          23m
pod/kube-proxy-d4jrh           1/1     Running   0          21m
pod/kube-proxy-q7hh7           1/1     Running   0          21m

NAME               TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)         AGE
service/kube-dns   ClusterIP   172.20.0.10   <none>        53/UDP,53/TCP   23m

NAME                        DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR   AGE
daemonset.apps/aws-node     2         2         2       2            2           <none>          23m
daemonset.apps/kube-proxy   2         2         2       2            2           <none>          23m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/coredns   2/2     2            2           23m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/coredns-5cb4fb54c7   2         2         2       23m

For your convenience, an AWS CloudFormation output will automatically be included in your template and will be printed when running cdk deploy.

NOTE: if the cluster is configured with kubectlEnabled: false, it will be created with the role/user that created the AWS CloudFormation stack. See Kubectl Support for details.

Kubernetes Resources

The KubernetesResource construct or cluster.addResource method can be used to apply Kubernetes resource manifests to this cluster.

The following examples will deploy the paulbouwer/hello-kubernetes service on the cluster:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
app_label = {"app": "hello-kubernetes"}

deployment = {
    "api_version": "apps/v1",
    "kind": "Deployment",
    "metadata": {"name": "hello-kubernetes"},
    "spec": {
        "replicas": 3,
        "selector": {"match_labels": app_label},
        "template": {
            "metadata": {"labels": app_label},
            "spec": {
                "containers": [{
                    "name": "hello-kubernetes",
                    "image": "paulbouwer/hello-kubernetes:1.5",
                    "ports": [{"container_port": 8080}]
                }
                ]
            }
        }
    }
}

service = {
    "api_version": "v1",
    "kind": "Service",
    "metadata": {"name": "hello-kubernetes"},
    "spec": {
        "type": "LoadBalancer",
        "ports": [{"port": 80, "target_port": 8080}],
        "selector": app_label
    }
}

# option 1: use a construct
KubernetesResource(self, "hello-kub",
    cluster=cluster,
    manifest=[deployment, service]
)

# or, option2: use `addResource`
cluster.add_resource("hello-kub", service, deployment)

Since Kubernetes resources are implemented as CloudFormation resources in the CDK. This means that if the resource is deleted from your code (or the stack is deleted), the next cdk deploy will issue a kubectl delete command and the Kubernetes resources will be deleted.

Dependencies

There are cases where Kubernetes resources must be deployed in a specific order. For example, you cannot define a resource in a Kubernetes namespace before the namespace was created.

You can represent dependencies between KubernetesResources using resource.node.addDependency():

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
namespace = cluster.add_resource("my-namespace",
    api_version="v1",
    kind="Namespace",
    metadata={"name": "my-app"}
)

service = cluster.add_resource("my-service",
    metadata={
        "name": "myservice",
        "namespace": "my-app"
    },
    spec=
)

service.node.add_dependency(namespace)

NOTE: when a KubernetesResource includes multiple resources (either directly or through cluster.addResource()) (e.g. cluster.addResource('foo', r1, r2, r3,...))), these resources will be applied as a single manifest via kubectl and will be applied sequentially (the standard behavior in kubectl).

Patching Kubernetes Resources

The KubernetesPatch construct can be used to update existing kubernetes resources. The following example can be used to patch the hello-kubernetes deployment from the example above with 5 replicas.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
KubernetesPatch(self, "hello-kub-deployment-label",
    cluster=cluster,
    resource_name="deployment/hello-kubernetes",
    apply_patch={"spec": {"replicas": 5}},
    restore_patch={"spec": {"replicas": 3}}
)

AWS IAM Mapping

As described in the Amazon EKS User Guide, you can map AWS IAM users and roles to Kubernetes Role-based access control (RBAC).

The Amazon EKS construct manages the aws-auth ConfigMap Kubernetes resource on your behalf and exposes an API through the cluster.awsAuth for mapping users, roles and accounts.

Furthermore, when auto-scaling capacity is added to the cluster (through cluster.addCapacity or cluster.addAutoScalingGroup), the IAM instance role of the auto-scaling group will be automatically mapped to RBAC so nodes can connect to the cluster. No manual mapping is required any longer.

NOTE: cluster.awsAuth will throw an error if your cluster is created with kubectlEnabled: false.

For example, let’s say you want to grant an IAM user administrative privileges on your cluster:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
admin_user = iam.User(self, "Admin")
cluster.aws_auth.add_user_mapping(admin_user, groups=["system:masters"])

A convenience method for mapping a role to the system:masters group is also available:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster.aws_auth.add_masters_role(role)

Cluster Security Group

When you create an Amazon EKS cluster, a cluster security group is automatically created as well. This security group is designed to allow all traffic from the control plane and managed node groups to flow freely between each other.

The ID for that security group can be retrieved after creating the cluster.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster_security_group_id = cluster.cluster_security_group_id

Cluster Encryption Configuration

When you create an Amazon EKS cluster, envelope encryption of Kubernetes secrets using the AWS Key Management Service (AWS KMS) can be enabled. The documentation on creating a cluster can provide more details about the customer master key (CMK) that can be used for the encryption.

The Amazon Resource Name (ARN) for that CMK can be retrieved.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cluster_encryption_config_key_arn = cluster.cluster_encryption_config_key_arn

Node ssh Access

If you want to be able to SSH into your worker nodes, you must already have an SSH key in the region you’re connecting to and pass it, and you must be able to connect to the hosts (meaning they must have a public IP and you should be allowed to connect to them on port 22):

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
asg = cluster.add_capacity("Nodes",
    instance_type=ec2.InstanceType("t2.medium"),
    vpc_subnets=SubnetSelection(subnet_type=ec2.SubnetType.PUBLIC),
    key_name="my-key-name"
)

# Replace with desired IP
asg.connections.allow_from(ec2.Peer.ipv4("1.2.3.4/32"), ec2.Port.tcp(22))

If you want to SSH into nodes in a private subnet, you should set up a bastion host in a public subnet. That setup is recommended, but is unfortunately beyond the scope of this documentation.

kubectl Support

When you create an Amazon EKS cluster, the IAM entity user or role, such as a federated user that creates the cluster, is automatically granted system:masters permissions in the cluster’s RBAC configuration.

In order to allow programmatically defining Kubernetes resources in your AWS CDK app and provisioning them through AWS CloudFormation, we will need to assume this “masters” role every time we want to issue kubectl operations against your cluster.

At the moment, the AWS::EKS::Cluster AWS CloudFormation resource does not support this behavior, so in order to support “programmatic kubectl”, such as applying manifests and mapping IAM roles from within your CDK application, the Amazon EKS construct library uses a custom resource for provisioning the cluster. This custom resource is executed with an IAM role that we can then use to issue kubectl commands.

The default behavior of this library is to use this custom resource in order to retain programmatic control over the cluster. In other words: to allow you to define Kubernetes resources in your CDK code instead of having to manage your Kubernetes applications through a separate system.

One of the implications of this design is that, by default, the user who provisioned the AWS CloudFormation stack (executed cdk deploy) will not have administrative privileges on the EKS cluster.

  1. Additional resources will be synthesized into your template (the AWS Lambda function, the role and policy).

  2. As described in Interacting with Your Cluster, if you wish to be able to manually interact with your cluster, you will need to map an IAM role or user to the system:masters group. This can be either done by specifying a mastersRole when the cluster is defined, calling cluster.awsAuth.addMastersRole or explicitly mapping an IAM role or IAM user to the relevant Kubernetes RBAC groups using cluster.addRoleMapping and/or cluster.addUserMapping.

If you wish to disable the programmatic kubectl behavior and use the standard AWS::EKS::Cluster resource, you can specify kubectlEnabled: false when you define the cluster:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
eks.Cluster(self, "cluster",
    kubectl_enabled=False
)

Take care: a change in this property will cause the cluster to be destroyed and a new cluster to be created.

When kubectl is disabled, you should be aware of the following:

  1. When you log-in to your cluster, you don’t need to specify --role-arn as long as you are using the same user that created the cluster.

  2. As described in the Amazon EKS User Guide, you will need to manually edit the aws-auth ConfigMap when you add capacity in order to map the IAM instance role to RBAC to allow nodes to join the cluster.

  3. Any eks.Cluster APIs that depend on programmatic kubectl support will fail with an error: cluster.addResource, cluster.addChart, cluster.awsAuth, props.mastersRole.

Helm Charts

The HelmChart construct or cluster.addChart method can be used to add Kubernetes resources to this cluster using Helm.

The following example will install the NGINX Ingress Controller to you cluster using Helm.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
# option 1: use a construct
HelmChart(self, "NginxIngress",
    cluster=cluster,
    chart="nginx-ingress",
    repository="https://helm.nginx.com/stable",
    namespace="kube-system"
)

# or, option2: use `addChart`
cluster.add_chart("NginxIngress",
    chart="nginx-ingress",
    repository="https://helm.nginx.com/stable",
    namespace="kube-system"
)

Helm charts will be installed and updated using helm upgrade --install, where a few parameters are being passed down (such as repo, values, version, namespace, wait, timeout, etc). This means that if the chart is added to CDK with the same release name, it will try to update the chart in the cluster. The chart will exists as CloudFormation resource.

Helm charts are implemented as CloudFormation resources in CDK. This means that if the chart is deleted from your code (or the stack is deleted), the next cdk deploy will issue a helm uninstall command and the Helm chart will be deleted.

When there is no release defined, the chart will be installed using the node.uniqueId, which will be lower cased and truncated to the last 63 characters.

By default, all Helm charts will be installed concurrently. In some cases, this could cause race conditions where two Helm charts attempt to deploy the same resource or if Helm charts depend on each other. You can use chart.node.addDependency() in order to declare a dependency order between charts:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
chart1 = cluster.add_chart(...)
chart2 = cluster.add_chart(...)

chart2.node.add_dependency(chart1)

Bottlerocket

Bottlerocket is a Linux-based open-source operating system that is purpose-built by Amazon Web Services for running containers on virtual machines or bare metal hosts. At this moment the managed nodegroup only supports Amazon EKS-optimized AMI but it’s possible to create a capacity of self-managed AutoScalingGroup running with bottlerocket Linux AMI.

NOTICE: Bottlerocket is in public preview and only available in some supported AWS regions.

The following example will create a capacity with self-managed Amazon EC2 capacity of 2 t3.small Linux instances running with Bottlerocket AMI.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
# add bottlerocket nodes
cluster.add_capacity("BottlerocketNodes",
    instance_type=ec2.InstanceType("t3.small"),
    min_capacity=2,
    machine_image_type=eks.MachineImageType.BOTTLEROCKET
)

To define only Bottlerocket capacity in your cluster, set defaultCapacity to 0 when you define the cluster as described above.

Please note Bottlerocket does not allow to customize bootstrap options and bootstrapOptions properties is not supported when you create the Bottlerocket capacity.

Service Accounts

With services account you can provide Kubernetes Pods access to AWS resources.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
# add service account
sa = cluster.add_service_account("MyServiceAccount")

bucket = Bucket(self, "Bucket")
bucket.grant_read_write(service_account)

mypod = cluster.add_resource("mypod",
    api_version="v1",
    kind="Pod",
    metadata={"name": "mypod"},
    spec={
        "service_account_name": sa.service_account_name,
        "containers": [{
            "name": "hello",
            "image": "paulbouwer/hello-kubernetes:1.5",
            "ports": [{"container_port": 8080}]
        }
        ]
    }
)

# create the resource after the service account
mypod.node.add_dependency(sa)

# print the IAM role arn for this service account
cdk.CfnOutput(self, "ServiceAccountIamRole", value=sa.role.role_arn)

Roadmap

  • [ ] AutoScaling (combine EC2 and Kubernetes scaling)