Terraform EKS Module

This repo contains a set of Terraform modules that can be used to provision an Elastic Kubernetes (EKS) cluster on AWS.

This module provides a way to provision an EKS cluster based on the current best practices employed at Cookpad.

Using this module

To provision an EKS cluster you need (as a minimum) to specify a name, and the details of the VPC network you will create it in.

module "cluster" {
  source  = "cookpad/eks/aws"
  version = "~> 1.25"

  name       = "hal-9000"

  vpc_config = {
    vpc_id = "vpc-345abc"

    public_subnet_ids = {
      use-east-1a = subnet-000af1234
      use-east-1b = subnet-123ae3456
      use-east-1c = subnet-456ab6789
    }

    private_subnet_ids = {
      use-east-1a = subnet-123af1234
      use-east-1b = subnet-456bc3456
      use-east-1c = subnet-789fe6789
    }
  }
}

provider "kubernetes" {
  host                   = module.cluster.config.endpoint
  cluster_ca_certificate = base64decode(module.cluster.config.ca_data)

  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command     = "aws"
    args        = ["eks", "get-token", "--cluster-name", module.cluster.config.name]
  }
}

There are many options that can be set to configure your cluster. Check the input documentation for more information.

Networking

If you only have simple networking requirements you can use the submodule cookpad/eks/aws/modules/vpc to create a VPC, it's output variable config can be used to configure the vpc_config variable.

Check the VPC module documentation for more extensive information.

Karpenter

We use karpenter to provision the nodes that run the workloads in our clusters. You can use the submodule cookpad/eks/aws/modules/vpc to provision the resources required to use karpenter, and a fargate profile to run the karpenter pods.

Check the Karpenter module documentation for more information.

Requirements

In order for this module to communicate with kubernetes correctly this module requires the aws cli to be installed and on your path.

You will need to initialise the kuberntes provider as shown in the example.

Multi User Environments

In an environment where multiple IAM users are used to running terraform run and terraform apply it is recommended to use the assume role functionality to assume a common IAM role in the aws provider definition.

provider "aws" {
  region              = "us-east-1"
  version             = "3.53.0"
  assume_role {
    role_arn = "arn:aws:iam::<your account id>:role/Terraform"
  }
}

see an example role here

Alternatively you should ensure that all users who need to run terraform are listed in the aws_auth_user_map variable of the cluster module.