terraform-aws-eks-cluster

Terraform module to provision an EKS cluster on AWS.

This Terraform module provisions a fully-configured AWS EKS (Elastic Kubernetes Service) cluster. It's engineered to integrate smoothly with Karpenter and EKS addons, forming a critical part of Cloud Posse's reference architecture. Ideal for teams looking to deploy scalable and manageable Kubernetes clusters on AWS with minimal fuss.

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Introduction

The module provisions the following resources:

• EKS cluster of master nodes that can be used together with the terraform-aws-eks-node-group and terraform-aws-eks-fargate-profile modules to create a full-blown EKS/Kubernetes cluster. You can also use the terraform-aws-eks-workers module to provision worker nodes for the cluster, but it is now rare for that to be a better choice than to use terraform-aws-eks-node-group.
• IAM Role to allow the cluster to access other AWS services
• EKS access entries to allow IAM users to access and administer the cluster

Usage

For a complete example, see examples/complete.

For automated tests of the complete example using bats and Terratest (which tests and deploys the example on AWS), see test/src.

Other examples:

• terraform-aws-components/eks/cluster - Cloud Posse's service catalog of "root module" invocations for provisioning reference architectures

  provider "aws" {
    region = var.region
  }

  # Note: This example creates an explicit access entry for the current user,
  # but in practice, you should use a static map of IAM users or roles that should have access to the cluster.
  # Granting access to the current user in this way is not recommended for production use.
  data "aws_caller_identity" "current" {}
  
  # IAM session context converts an assumed role ARN into an IAM Role ARN.
  # Again, this is primarily to simplify the example, and in practice, you should use a static map of IAM users or roles.
  data "aws_iam_session_context" "current" {
    arn = data.aws_caller_identity.current.arn
  }
  
  locals {
    # The usage of the specific kubernetes.io/cluster/* resource tags below are required
    # for EKS and Kubernetes to discover and manage networking resources
    # https://aws.amazon.com/premiumsupport/knowledge-center/eks-vpc-subnet-discovery/
    # https://github.com/kubernetes-sigs/aws-load-balancer-controller/blob/main/docs/deploy/subnet_discovery.md
    tags = { "kubernetes.io/cluster/${module.label.id}" = "shared" }
  
    # required tags to make ALB ingress work https://docs.aws.amazon.com/eks/latest/userguide/alb-ingress.html
    public_subnets_additional_tags = {
      "kubernetes.io/role/elb" : 1
    }
    private_subnets_additional_tags = {
      "kubernetes.io/role/internal-elb" : 1
    }
  
    # Enable the IAM user creating the cluster to administer it,
    # without using the bootstrap_cluster_creator_admin_permissions option,
    # as an example of how to use the access_entry_map feature.
    # In practice, this should be replaced with a static map of IAM users or roles
    # that should have access to the cluster, but we use the current user
    # to simplify the example.
    access_entry_map = {
      (data.aws_iam_session_context.current.issuer_arn) = {
        access_policy_associations = {
          ClusterAdmin = {}
        }
      }
    }
  }

  module "label" {
    source = "cloudposse/label/null"
    # Cloud Posse recommends pinning every module to a specific version
    # version  = "x.x.x"

    namespace  = var.namespace
    name       = var.name
    stage      = var.stage
    delimiter  = var.delimiter
    tags       = var.tags
  }

  module "vpc" {
    source = "cloudposse/vpc/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version     = "x.x.x"

    ipv4_primary_cidr_block = "172.16.0.0/16"

    tags    = local.tags
    context = module.label.context
  }

  module "subnets" {
    source = "cloudposse/dynamic-subnets/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version     = "x.x.x"

    availability_zones   = var.availability_zones
    vpc_id               = module.vpc.vpc_id
    igw_id               = [module.vpc.igw_id]
    ipv4_cidr_block      = [module.vpc.vpc_cidr_block]
    nat_gateway_enabled  = true
    nat_instance_enabled = false

    public_subnets_additional_tags  = local.public_subnets_additional_tags
    private_subnets_additional_tags = local.private_subnets_additional_tags

    tags    = local.tags
    context = module.label.context
  }

  module "eks_node_group" {
    source = "cloudposse/eks-node-group/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version     = "x.x.x"

    instance_types    = [var.instance_type]
    subnet_ids        = module.subnets.private_subnet_ids
    health_check_type = var.health_check_type
    min_size          = var.min_size
    max_size          = var.max_size
    cluster_name      = module.eks_cluster.eks_cluster_id

    # Enable the Kubernetes cluster auto-scaler to find the auto-scaling group
    cluster_autoscaler_enabled = var.autoscaling_policies_enabled

    context = module.label.context
  }

  module "eks_cluster" {
    source = "cloudposse/eks-cluster/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version = "x.x.x"

    subnet_ids            = concat(module.subnets.private_subnet_ids, module.subnets.public_subnet_ids)
    kubernetes_version    = var.kubernetes_version
    oidc_provider_enabled = true

    addons = [
      # https://docs.aws.amazon.com/eks/latest/userguide/managing-vpc-cni.html#vpc-cni-latest-available-version
      {
        addon_name                  = "vpc-cni"
        addon_version               = var.vpc_cni_version
        resolve_conflicts_on_create = "OVERWRITE"
        resolve_conflicts_on_update = "OVERWRITE"
        service_account_role_arn    = var.vpc_cni_service_account_role_arn # Creating this role is outside the scope of this example
      },
      # https://docs.aws.amazon.com/eks/latest/userguide/managing-kube-proxy.html
      {
        addon_name                  = "kube-proxy"
        addon_version               = var.kube_proxy_version
        resolve_conflicts_on_create = "OVERWRITE"
        resolve_conflicts_on_update = "OVERWRITE"
        service_account_role_arn    = null
      },
      # https://docs.aws.amazon.com/eks/latest/userguide/managing-coredns.html
      {
        addon_name                  = "coredns"
        addon_version               = var.coredns_version
        resolve_conflicts_on_create = "OVERWRITE"
        resolve_conflicts_on_update = "OVERWRITE"
        service_account_role_arn    = null
      },
    ]
    addons_depends_on = [module.eks_node_group]

    context = module.label.context

    cluster_depends_on = [module.subnets]
  }

Module usage with two unmanaged worker groups:

  locals {
    # Unfortunately, the `aws_ami` data source attribute `most_recent` (https://github.com/cloudposse/terraform-aws-eks-workers/blob/34a43c25624a6efb3ba5d2770a601d7cb3c0d391/main.tf#L141)
    # does not work as you might expect. If you are not going to use a custom AMI you should
    # use the `eks_worker_ami_name_filter` variable to set the right kubernetes version for EKS workers,
    # otherwise the first version of Kubernetes supported by AWS (v1.11) for EKS workers will be selected, but the
    # EKS control plane will ignore it to use one that matches the version specified by the `kubernetes_version` variable.
    eks_worker_ami_name_filter = "amazon-eks-node-${var.kubernetes_version}*"
  }

  module "eks_workers" {
    source = "cloudposse/eks-workers/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version     = "x.x.x"

    attributes                         = ["small"]
    instance_type                      = "t3.small"
    eks_worker_ami_name_filter         = local.eks_worker_ami_name_filter
    vpc_id                             = module.vpc.vpc_id
    subnet_ids                         = module.subnets.public_subnet_ids
    health_check_type                  = var.health_check_type
    min_size                           = var.min_size
    max_size                           = var.max_size
    wait_for_capacity_timeout          = var.wait_for_capacity_timeout
    cluster_name                       = module.label.id
    cluster_endpoint                   = module.eks_cluster.eks_cluster_endpoint
    cluster_certificate_authority_data = module.eks_cluster.eks_cluster_certificate_authority_data
    cluster_security_group_id          = module.eks_cluster.eks_cluster_managed_security_group_id

    # Auto-scaling policies and CloudWatch metric alarms
    autoscaling_policies_enabled           = var.autoscaling_policies_enabled
    cpu_utilization_high_threshold_percent = var.cpu_utilization_high_threshold_percent
    cpu_utilization_low_threshold_percent  = var.cpu_utilization_low_threshold_percent

    context = module.label.context
  }

  module "eks_workers_2" {
    source = "cloudposse/eks-workers/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version     = "x.x.x"

    attributes                         = ["medium"]
    instance_type                      = "t3.medium"
    eks_worker_ami_name_filter         = local.eks_worker_ami_name_filter
    vpc_id                             = module.vpc.vpc_id
    subnet_ids                         = module.subnets.public_subnet_ids
    health_check_type                  = var.health_check_type
    min_size                           = var.min_size
    max_size                           = var.max_size
    wait_for_capacity_timeout          = var.wait_for_capacity_timeout
    cluster_name                       = module.label.id
    cluster_endpoint                   = module.eks_cluster.eks_cluster_endpoint
    cluster_certificate_authority_data = module.eks_cluster.eks_cluster_certificate_authority_data
    cluster_security_group_id          = module.eks_cluster.eks_cluster_managed_security_group_id

    # Auto-scaling policies and CloudWatch metric alarms
    autoscaling_policies_enabled           = var.autoscaling_policies_enabled
    cpu_utilization_high_threshold_percent = var.cpu_utilization_high_threshold_percent
    cpu_utilization_low_threshold_percent  = var.cpu_utilization_low_threshold_percent

    context = module.label.context
  }

  module "eks_cluster" {
    source = "cloudposse/eks-cluster/aws"
    # Cloud Posse recommends pinning every module to a specific version
    # version     = "x.x.x"

    subnet_ids            = concat(module.subnets.private_subnet_ids, module.subnets.public_subnet_ids)
    kubernetes_version    = var.kubernetes_version
    oidc_provider_enabled = true # needed for VPC CNI

    access_entries_for_nodes = {
      EC2_LINUX = [module.eks_workers.workers_role_arn, module.eks_workers_2.workers_role_arn]
    }

    context = module.label.context
  }

[!WARNING] Release 4.0.0 contains major breaking changes that will require you to update your existing EKS cluster and configuration to use this module. Please see the v3 to v4 migration path for more information. Release 2.0.0 (previously released as version 0.45.0) contains some changes that, if applied to a cluster created with an earlier version of this module, could result in your existing EKS cluster being replaced (destroyed and recreated). To prevent this, follow the instructions in the v1 to v2 migration path.

[!NOTE] Prior to v4 of this module, AWS did not provide an API to manage access to the EKS cluster, causing numerous challenges. With v4 of this module, it exclusively uses the AWS API, resolving many issues you may read about that had affected prior versions. See the version 2 README and release notes for more information on the challenges and workarounds that were required prior to v3.

[!IMPORTANT] In Cloud Posse's examples, we avoid pinning modules to specific versions to prevent discrepancies between the documentation and the latest released versions. However, for your own projects, we strongly advise pinning each module to the exact version you're using. This practice ensures the stability of your infrastructure. Additionally, we recommend implementing a systematic approach for updating versions to avoid unexpected changes.

Makefile Targets

Available targets:

  help                                Help screen
  help/all                            Display help for all targets
  help/short                          This help short screen
  lint                                Lint terraform code

Requirements

Providers

Modules

Resources

Inputs

object({
    authentication_mode                         = optional(string, "API")
    bootstrap_cluster_creator_admin_permissions = optional(bool, false)
  })

list(object({
    principal_arn     = string
    user_name         = optional(string, null)
    kubernetes_groups = optional(list(string), null)
  }))

map(object({
    # key is principal_arn
    user_name = optional(string)
    # Cannot assign "system:*" groups to IAM users, use ClusterAdmin and Admin instead
    kubernetes_groups = optional(list(string), [])
    type              = optional(string, "STANDARD")
    access_policy_associations = optional(map(object({
      # key is policy_arn or policy_name
      access_scope = optional(object({
        type       = optional(string, "cluster")
        namespaces = optional(list(string))
      }), {}) # access_scope
    })), {})  # access_policy_associations
  }))

list(object({
    principal_arn = string
    policy_arn    = string
    access_scope = object({
      type       = optional(string, "cluster")
      namespaces = optional(list(string))
    })
  }))

list(object({
    addon_name           = string
    addon_version        = optional(string, null)
    configuration_values = optional(string, null)
    # resolve_conflicts is deprecated, but we keep it for backwards compatibility
    # and because if not declared, Terraform will silently ignore it.
    resolve_conflicts           = optional(string, null)
    resolve_conflicts_on_create = optional(string, null)
    resolve_conflicts_on_update = optional(string, null)
    service_account_role_arn    = optional(string, null)
    create_timeout              = optional(string, null)
    update_timeout              = optional(string, null)
    delete_timeout              = optional(string, null)
  }))

[
  "cluster"
]

[
  "secrets"
]

{
  "additional_tag_map": {},
  "attributes": [],
  "delimiter": null,
  "descriptor_formats": {},
  "enabled": true,
  "environment": null,
  "id_length_limit": null,
  "label_key_case": null,
  "label_order": [],
  "label_value_case": null,
  "labels_as_tags": [
    "unset"
  ],
  "name": null,
  "namespace": null,
  "regex_replace_chars": null,
  "stage": null,
  "tags": {},
  "tenant": null
}

list(object({
    description              = string
    from_port                = number
    to_port                  = number
    protocol                 = string
    source_security_group_id = string
  }))

[
  "default"
]

[
  "0.0.0.0/0"
]

Outputs

Related Projects

Check out these related projects.

• terraform-aws-components eks/clusters - Cloud Posse's component (root module) using this module to provision an EKS cluster
• terraform-aws-components eks/karpenter and eks/karpenter-provisioner - Cloud Posse's components (root modules) deploying Karpenter to manage auto-scaling of EKS node groups
• terraform-aws-eks-workers - Terraform module to provision an AWS AutoScaling Group, IAM Role, and Security Group for EKS Workers
• terraform-aws-ec2-autoscale-group - Terraform module to provision Auto Scaling Group and Launch Template on AWS
• terraform-aws-ecs-container-definition - Terraform module to generate well-formed JSON documents (container definitions) that are passed to the aws_ecs_task_definition Terraform resource
• terraform-aws-ecs-alb-service-task - Terraform module which implements an ECS service which exposes a web service via ALB
• terraform-aws-ecs-web-app - Terraform module that implements a web app on ECS and supports autoscaling, CI/CD, monitoring, ALB integration, and much more
• terraform-aws-ecs-codepipeline - Terraform module for CI/CD with AWS Code Pipeline and Code Build for ECS
• terraform-aws-ecs-cloudwatch-autoscaling - Terraform module to autoscale ECS Service based on CloudWatch metrics
• terraform-aws-ecs-cloudwatch-sns-alarms - Terraform module to create CloudWatch Alarms on ECS Service level metrics
• terraform-aws-ec2-instance - Terraform module for providing a general purpose EC2 instance
• terraform-aws-ec2-instance-group - Terraform module for provisioning multiple general purpose EC2 hosts for stateful applications

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License

Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

  https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.

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