Use AWS API for EKS authentication and authorization (#206)

Author: Nuru

.github/renovate.json

@@ -1,6 +1,6 @@
 {
   "extends": [
-    "config:base",
+    "config:recommended",
     ":preserveSemverRanges",
     ":rebaseStalePrs"
   ],
@@ -9,6 +9,18 @@
   "dependencyDashboardAutoclose": true,
   "enabledManagers": ["terraform"],
   "terraform": {
-    "ignorePaths": ["**/context.tf"]
-  }
+    "ignorePaths": ["**/context.tf", "**/examples/obsolete*/**"]
+  },
+  "timezone": "America/New_York",
+  "packageRules": [
+    {
+      "matchFileNames": [
+        "/*.tf",
+        "examples/complete/*.tf"
+      ],
+      "groupName": "all",
+      "schedule": ["every 4 weeks on wednesday at 04:00 am"],
+      "groupSlug": "monthly"
+    }
+  ]
 }

LICENSE

@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright 2018-2023 Cloud Posse, LLC
+   Copyright 2018-2024 Cloud Posse, LLC
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

README.md

@@ -1,157 +1,130 @@
-# The EKS service does not provide a cluster-level API parameter or resource to automatically configure the underlying Kubernetes cluster
-# to allow worker nodes to join the cluster via AWS IAM role authentication.
-
-# NOTE: To automatically apply the Kubernetes configuration to the cluster (which allows the worker nodes to join the cluster),
-# the requirements outlined here must be met:
-# https://learn.hashicorp.com/terraform/aws/eks-intro#preparation
-# https://learn.hashicorp.com/terraform/aws/eks-intro#configuring-kubectl-for-eks
-# https://learn.hashicorp.com/terraform/aws/eks-intro#required-kubernetes-configuration-to-join-worker-nodes
-
-# Additional links
-# https://learn.hashicorp.com/terraform/aws/eks-intro
-# https://itnext.io/how-does-client-authentication-work-on-amazon-eks-c4f2b90d943b
-# https://docs.aws.amazon.com/eks/latest/userguide/create-kubeconfig.html
-# https://docs.aws.amazon.com/eks/latest/userguide/add-user-role.html
-# https://docs.aws.amazon.com/cli/latest/reference/eks/update-kubeconfig.html
-# https://docs.aws.amazon.com/en_pv/eks/latest/userguide/create-kubeconfig.html
-# https://itnext.io/kubernetes-authorization-via-open-policy-agent-a9455d9d5ceb
-# http://marcinkaszynski.com/2018/07/12/eks-auth.html
-# https://cloud.google.com/kubernetes-engine/docs/concepts/configmap
-# http://yaml-multiline.info
-# https://github.com/terraform-providers/terraform-provider-kubernetes/issues/216
-# https://www.terraform.io/docs/cloud/run/install-software.html
-# https://stackoverflow.com/questions/26123740/is-it-possible-to-install-aws-cli-package-without-root-permission
-# https://stackoverflow.com/questions/58232731/kubectl-missing-form-terraform-cloud
-# https://docs.aws.amazon.com/cli/latest/userguide/install-bundle.html
-# https://docs.aws.amazon.com/cli/latest/userguide/install-cliv1.html
-
 
 locals {
-  yaml_quote = var.aws_auth_yaml_strip_quotes ? "" : "\""
-
-  need_kubernetes_provider = local.enabled && var.apply_config_map_aws_auth
-
-  kubeconfig_path_enabled = local.need_kubernetes_provider && var.kubeconfig_path_enabled
-  kube_exec_auth_enabled  = local.kubeconfig_path_enabled ? false : local.need_kubernetes_provider && var.kube_exec_auth_enabled
-  kube_data_auth_enabled  = local.kube_exec_auth_enabled ? false : local.need_kubernetes_provider && var.kube_data_auth_enabled
-
-  exec_profile = local.kube_exec_auth_enabled && var.kube_exec_auth_aws_profile_enabled ? ["--profile", var.kube_exec_auth_aws_profile] : []
-  exec_role    = local.kube_exec_auth_enabled && var.kube_exec_auth_role_arn_enabled ? ["--role-arn", var.kube_exec_auth_role_arn] : []
-
-  cluster_endpoint_data     = join("", aws_eks_cluster.default[*].endpoint) # use `join` instead of `one` to keep the value a string
-  cluster_auth_map_endpoint = var.apply_config_map_aws_auth ? local.cluster_endpoint_data : var.dummy_kubeapi_server
-
-  certificate_authority_data_list          = coalescelist(aws_eks_cluster.default[*].certificate_authority, [[{ data : "" }]])
-  certificate_authority_data_list_internal = local.certificate_authority_data_list[0]
-  certificate_authority_data_map           = local.certificate_authority_data_list_internal[0]
-  certificate_authority_data               = local.certificate_authority_data_map["data"]
-
-  # Add worker nodes role ARNs (could be from many un-managed worker groups) to the ConfigMap
-  # Note that we don't need to do this for managed Node Groups since EKS adds their roles to the ConfigMap automatically
-  map_worker_roles = [
-    for role_arn in var.workers_role_arns : {
-      rolearn  = role_arn
-      username = "system:node:{{EC2PrivateDNSName}}"
-      groups = [
-        "system:bootstrappers",
-        "system:nodes"
-      ]
-    }
-  ]
-}
+  # Extract the cluster certificate for use in OIDC configuration
+  certificate_authority_data = try(aws_eks_cluster.default[0].certificate_authority[0]["data"], "")
+
+  eks_policy_short_abbreviation_map = {
+    # List available policies with `aws eks list-access-policies --output table`
+
+    Admin        = "arn:aws:eks::aws:cluster-access-policy/AmazonEKSAdminPolicy"
+    ClusterAdmin = "arn:aws:eks::aws:cluster-access-policy/AmazonEKSClusterAdminPolicy"
+    Edit         = "arn:aws:eks::aws:cluster-access-policy/AmazonEKSEditPolicy"
+    View         = "arn:aws:eks::aws:cluster-access-policy/AmazonEKSViewPolicy"
+    # Add new policies here
+  }
+
+  eks_policy_abbreviation_map = merge({ for k, v in local.eks_policy_short_abbreviation_map : format("AmazonEKS%sPolicy", k) => v },
+  local.eks_policy_short_abbreviation_map)
 
-resource "null_resource" "wait_for_cluster" {
-  count = local.enabled && var.apply_config_map_aws_auth ? 1 : 0
-  depends_on = [
-    aws_eks_cluster.default,
-    aws_security_group_rule.custom_ingress_rules,
-    aws_security_group_rule.managed_ingress_security_groups,
-    aws_security_group_rule.managed_ingress_cidr_blocks,
-  ]
-
-  provisioner "local-exec" {
-    command     = var.wait_for_cluster_command
-    interpreter = var.local_exec_interpreter
-    environment = {
-      ENDPOINT = local.cluster_endpoint_data
-    }
+
+  # Expand abbreviated access policies to full ARNs
+  access_entry_expanded_map = { for k, v in var.access_entry_map : k => merge({
+    # Expand abbreviated policies to full ARNs
+    access_policy_associations = { for kk, vv in v.access_policy_associations : try(local.eks_policy_abbreviation_map[kk], kk) => vv }
+    # Copy over all other fields
+    }, { for kk, vv in v : kk => vv if kk != "access_policy_associations" })
+  }
+
+  # Replace membership in "system:masters" group with association to "ClusterAdmin" policy
+  access_entry_map = { for k, v in local.access_entry_expanded_map : k => merge({
+    # Remove "system:masters" group from standard users
+    kubernetes_groups = [for group in v.kubernetes_groups : group if group != "system:masters" || v.type != "STANDARD"]
+    access_policy_associations = merge(
+      # copy all existing associations
+      v.access_policy_associations,
+      # add "ClusterAdmin" policy if the user was in "system:masters" group and is a standard user
+      contains(v.kubernetes_groups, "system:masters") && v.type == "STANDARD" ? {
+        "arn:aws:eks::aws:cluster-access-policy/AmazonEKSClusterAdminPolicy" = {
+          access_scope = {
+            type       = "cluster"
+            namespaces = null
+          }
+        }
+      } : {}
+    )
+    # Copy over all other fields
+    }, { for kk, vv in v : kk => vv if kk != "kubernetes_groups" && kk != "access_policy_associations" })
   }
+
+  eks_access_policy_association_product_map = merge(flatten([
+    for k, v in local.access_entry_map : [for kk, vv in v.access_policy_associations : { format("%s-%s", k, kk) = {
+      principal_arn = k
+      policy_arn    = kk
+      }
+    }]
+  ])...)
 }
 
+# The preferred way to keep track of entries is by key, but we also support list,
+# because keys need to be known at plan time, but list values do not.
+resource "aws_eks_access_entry" "map" {
+  for_each = local.enabled ? local.access_entry_map : {}
+
+  cluster_name      = local.eks_cluster_id
+  principal_arn     = each.key
+  kubernetes_groups = each.value.kubernetes_groups
+  type              = each.value.type
 
-# Get an authentication token to communicate with the EKS cluster.
-# By default (before other roles are added to the Auth ConfigMap), you can authenticate to EKS cluster only by assuming the role that created the cluster.
-# `aws_eks_cluster_auth` uses IAM credentials from the AWS provider to generate a temporary token.
-# If the AWS provider assumes an IAM role, `aws_eks_cluster_auth` will use the same IAM role to get the auth token.
-# https://www.terraform.io/docs/providers/aws/d/eks_cluster_auth.html
-#
-# You can set `kube_exec_auth_enabled` to use a different IAM Role or AWS config profile to fetch the auth token
-#
-data "aws_eks_cluster_auth" "eks" {
-  count = local.kube_data_auth_enabled ? 1 : 0
-  name  = one(aws_eks_cluster.default[*].id)
+  tags = module.this.tags
 }
 
+resource "aws_eks_access_policy_association" "map" {
+  for_each = local.enabled ? local.eks_access_policy_association_product_map : {}
+
+  cluster_name  = local.eks_cluster_id
+  principal_arn = each.value.principal_arn
+  policy_arn    = each.value.policy_arn
 
-provider "kubernetes" {
-  # Without a dummy API server configured, the provider will throw an error and prevent a "plan" from succeeding
-  # in situations where Terraform does not provide it with the cluster endpoint before triggering an API call.
-  # Since those situations are limited to ones where we do not care about the failure, such as fetching the
-  # ConfigMap before the cluster has been created or in preparation for deleting it, and the worst that will
-  # happen is that the aws-auth ConfigMap will be unnecessarily updated, it is just better to ignore the error
-  # so we can proceed with the task of creating or destroying the cluster.
-  #
-  # If this solution bothers you, you can disable it by setting var.dummy_kubeapi_server = null
-  host                   = local.cluster_auth_map_endpoint
-  cluster_ca_certificate = local.enabled && !local.kubeconfig_path_enabled ? base64decode(local.certificate_authority_data) : null
-  token                  = local.kube_data_auth_enabled ? one(data.aws_eks_cluster_auth.eks[*].token) : null
-  # The Kubernetes provider will use information from KUBECONFIG if it exists, but if the default cluster
-  # in KUBECONFIG is some other cluster, this will cause problems, so we override it always.
-  config_path    = local.kubeconfig_path_enabled ? var.kubeconfig_path : ""
-  config_context = var.kubeconfig_context
-
-  dynamic "exec" {
-    for_each = local.kube_exec_auth_enabled && length(local.cluster_endpoint_data) > 0 ? ["exec"] : []
-    content {
-      api_version = "client.authentication.k8s.io/v1beta1"
-      command     = "aws"
-      args        = concat(local.exec_profile, ["eks", "get-token", "--cluster-name", try(aws_eks_cluster.default[0].id, "deleted")], local.exec_role)
-    }
+  access_scope {
+    type       = local.access_entry_map[each.value.principal_arn].access_policy_associations[each.value.policy_arn].access_scope.type
+    namespaces = local.access_entry_map[each.value.principal_arn].access_policy_associations[each.value.policy_arn].access_scope.namespaces
   }
 }
 
-resource "kubernetes_config_map" "aws_auth_ignore_changes" {
-  count      = local.enabled && var.apply_config_map_aws_auth && var.kubernetes_config_map_ignore_role_changes ? 1 : 0
-  depends_on = [null_resource.wait_for_cluster]
+# We could combine all the list access entries into a single resource,
+# but separating them by category minimizes the ripple effect of changes
+# due to adding and removing items from the list.
+resource "aws_eks_access_entry" "standard" {
+  count = local.enabled ? length(var.access_entries) : 0
 
-  metadata {
-    name      = "aws-auth"
-    namespace = "kube-system"
-  }
+  cluster_name      = local.eks_cluster_id
+  principal_arn     = var.access_entries[count.index].principal_arn
+  kubernetes_groups = var.access_entries[count.index].kubernetes_groups
+  type              = "STANDARD"
 
-  data = {
-    mapRoles    = yamlencode(distinct(concat(local.map_worker_roles, var.map_additional_iam_roles)))
-    mapUsers    = yamlencode(var.map_additional_iam_users)
-    mapAccounts = yamlencode(var.map_additional_aws_accounts)
-  }
+  tags = module.this.tags
+}
 
-  lifecycle {
-    ignore_changes = [data["mapRoles"]]
-  }
+resource "aws_eks_access_entry" "linux" {
+  count = local.enabled ? length(lookup(var.access_entries_for_nodes, "EC2_LINUX", [])) : 0
+
+  cluster_name  = local.eks_cluster_id
+  principal_arn = var.access_entries_for_nodes.EC2_LINUX[count.index]
+  type          = "EC2_LINUX"
+
+  tags = module.this.tags
 }
 
-resource "kubernetes_config_map" "aws_auth" {
-  count      = local.enabled && var.apply_config_map_aws_auth && var.kubernetes_config_map_ignore_role_changes == false ? 1 : 0
-  depends_on = [null_resource.wait_for_cluster]
+resource "aws_eks_access_entry" "windows" {
+  count = local.enabled ? length(lookup(var.access_entries_for_nodes, "EC2_WINDOWS", [])) : 0
 
-  metadata {
-    name      = "aws-auth"
-    namespace = "kube-system"
-  }
+  cluster_name  = local.eks_cluster_id
+  principal_arn = var.access_entries_for_nodes.EC2_WINDOWS[count.index]
+  type          = "EC2_WINDOWS"
+
+  tags = module.this.tags
+}
+
+resource "aws_eks_access_policy_association" "list" {
+  count = local.enabled ? length(var.access_policy_associations) : 0
+
+  cluster_name  = local.eks_cluster_id
+  principal_arn = var.access_policy_associations[count.index].principal_arn
+  policy_arn = try(local.eks_policy_abbreviation_map[var.access_policy_associations[count.index].policy_arn],
+  var.access_policy_associations[count.index].policy_arn)
 
-  data = {
-    mapRoles    = replace(yamlencode(distinct(concat(local.map_worker_roles, var.map_additional_iam_roles))), "\"", local.yaml_quote)
-    mapUsers    = replace(yamlencode(var.map_additional_iam_users), "\"", local.yaml_quote)
-    mapAccounts = replace(yamlencode(var.map_additional_aws_accounts), "\"", local.yaml_quote)
+  access_scope {
+    type       = var.access_policy_associations[count.index].access_scope.type
+    namespaces = var.access_policy_associations[count.index].access_scope.namespaces
   }
 }

README.yaml

@@ -10,7 +10,9 @@ by the user, to ensure the nodes and control plane can communicate.
 Before version 2, this module, by default, created an additional Security Group. Prior to version `0.19.0` of this module, that additional Security Group was the only one exposed by
 this module (because EKS at the time did not create the managed Security Group for the cluster), and it was intended that all worker nodes (managed and unmanaged) be placed in this
 additional Security Group. With version `0.19.0`, this module exposed the managed Security Group created by the EKS cluster, in which all managed node groups are placed by default. We now
-recommend placing non-managed node groups in the EKS-created Security Group as well by using the `allowed_security_group_ids` variable, and not create an additional Security Group.
+recommend placing non-managed node groups in the EKS-created Security Group 
+as well by using the `eks_cluster_managed_security_group_id` output to 
+associate the node groups with it, and not create an additional Security Group.
 
 See https://docs.aws.amazon.com/eks/latest/userguide/sec-group-reqs.html for more details.