Support custom IAM roles for cluster and workers (#338)

* allow specifying custom worker IAM instance profiles

* allow specifying custom cluster IAM role

* add doc

* update changelog

* use data.aws_iam_instance_profile.name

Author: erks

CHANGELOG.md

@@ -12,6 +12,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 - Added support for custom service linked role for Auto Scaling group (by @voanhduy1512)
+- Added support for custom IAM roles for cluster and workers (by @erks)
 - Add cluster arn to outputs (by @alexsn)
 - Added outputs for `workers_user_data` and `workers_default_ami_id` (by @max-rocket-internet)
 - Added doc about spot instances (by @max-rocket-internet)

README.md

@@ -118,6 +118,7 @@ MIT Licensed. See [LICENSE](https://github.com/terraform-aws-modules/terraform-a
 | cluster\_enabled\_log\_types | A list of the desired control plane logging to enable. For more information, see Amazon EKS Control Plane Logging documentation (https://docs.aws.amazon.com/eks/latest/userguide/control-plane-logs.html) | list | `[]` | no |
 | cluster\_endpoint\_private\_access | Indicates whether or not the Amazon EKS private API server endpoint is enabled. | string | `"false"` | no |
 | cluster\_endpoint\_public\_access | Indicates whether or not the Amazon EKS public API server endpoint is enabled. | string | `"true"` | no |
+| cluster\_iam\_role\_name | IAM role name for the cluster. Only applicable if manage_cluster_iam_resources is set to false. | string | `""` | no |
 | cluster\_name | Name of the EKS cluster. Also used as a prefix in names of related resources. | string | n/a | yes |
 | cluster\_security\_group\_id | If provided, the EKS cluster will be attached to this security group. If not given, a security group will be created with necessary ingres/egress to work with the workers and provide API access to your current IP/32. | string | `""` | no |
 | cluster\_version | Kubernetes version to use for the EKS cluster. | string | `"1.12"` | no |
@@ -130,6 +131,8 @@ MIT Licensed. See [LICENSE](https://github.com/terraform-aws-modules/terraform-a
 | kubeconfig\_name | Override the default name used for items kubeconfig. | string | `""` | no |
 | local\_exec\_interpreter | Command to run for local-exec resources. Must be a shell-style interpreter. If you are on Windows Git Bash is a good choice. | list | `[ "/bin/sh", "-c" ]` | no |
 | manage\_aws\_auth | Whether to apply the aws-auth configmap file. | string | `"true"` | no |
+| manage\_cluster\_iam\_resources | Whether to let the module manage cluster IAM resources. If set to false, cluster_iam_role_name must be specified. | string | `"true"` | no |
+| manage\_worker\_iam\_resources | Whether to let the module manage worker IAM resources. If set to false, iam_instance_profile_name must be specified for workers. | string | `"true"` | no |
 | map\_accounts | Additional AWS account numbers to add to the aws-auth configmap. See examples/eks_test_fixture/variables.tf for example format. | list | `[]` | no |
 | map\_accounts\_count | The count of accounts in the map_accounts list. | string | `"0"` | no |
 | map\_roles | Additional IAM roles to add to the aws-auth configmap. See examples/eks_test_fixture/variables.tf for example format. | list | `[]` | no |

aws_auth.tf

@@ -39,7 +39,7 @@ data "template_file" "launch_template_worker_role_arns" {
   template = "${file("${path.module}/templates/worker-role.tpl")}"
 
   vars {
-    worker_role_arn = "arn:aws:iam::${data.aws_caller_identity.current.account_id}:role/${element(aws_iam_instance_profile.workers_launch_template.*.role, count.index)}"
+    worker_role_arn = "arn:aws:iam::${data.aws_caller_identity.current.account_id}:role/${element(coalescelist(aws_iam_instance_profile.workers_launch_template.*.role, data.aws_iam_instance_profile.custom_worker_group_launch_template_iam_instance_profile.*.role_name), count.index)}"
   }
 }
 
@@ -48,7 +48,7 @@ data "template_file" "worker_role_arns" {
   template = "${file("${path.module}/templates/worker-role.tpl")}"
 
   vars {
-    worker_role_arn = "arn:aws:iam::${data.aws_caller_identity.current.account_id}:role/${element(aws_iam_instance_profile.workers.*.role, count.index)}"
+    worker_role_arn = "arn:aws:iam::${data.aws_caller_identity.current.account_id}:role/${element(coalescelist(aws_iam_instance_profile.workers.*.role, data.aws_iam_instance_profile.custom_worker_group_iam_instance_profile.*.role_name), count.index)}"
   }
 }
 

cluster.tf

@@ -1,7 +1,7 @@
 resource "aws_eks_cluster" "this" {
   name                      = "${var.cluster_name}"
   enabled_cluster_log_types = "${var.cluster_enabled_log_types}"
-  role_arn                  = "${aws_iam_role.cluster.arn}"
+  role_arn                  = "${local.cluster_iam_role_arn}"
   version                   = "${var.cluster_version}"
 
   vpc_config {
@@ -58,14 +58,17 @@ resource "aws_iam_role" "cluster" {
   permissions_boundary  = "${var.permissions_boundary}"
   path                  = "${var.iam_path}"
   force_detach_policies = true
+  count                 = "${var.manage_cluster_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_role_policy_attachment" "cluster_AmazonEKSClusterPolicy" {
   policy_arn = "arn:aws:iam::aws:policy/AmazonEKSClusterPolicy"
   role       = "${aws_iam_role.cluster.name}"
+  count      = "${var.manage_cluster_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_role_policy_attachment" "cluster_AmazonEKSServicePolicy" {
   policy_arn = "arn:aws:iam::aws:policy/AmazonEKSServicePolicy"
   role       = "${aws_iam_role.cluster.name}"
+  count      = "${var.manage_cluster_iam_resources ? 1 : 0}"
 }

data.tf

@@ -100,3 +100,18 @@ data "template_file" "launch_template_userdata" {
     kubelet_extra_args   = "${lookup(var.worker_groups_launch_template[count.index], "kubelet_extra_args", local.workers_group_launch_template_defaults["kubelet_extra_args"])}"
   }
 }
+
+data "aws_iam_role" "custom_cluster_iam_role" {
+  name  = "${var.cluster_iam_role_name}"
+  count = "${var.manage_cluster_iam_resources ? 0 : 1}"
+}
+
+data "aws_iam_instance_profile" "custom_worker_group_iam_instance_profile" {
+  name  = "${lookup(var.worker_groups[count.index], "iam_instance_profile_name", local.workers_group_defaults["iam_instance_profile_name"])}"
+  count = "${var.manage_worker_iam_resources ? 0 : var.worker_group_count}"
+}
+
+data "aws_iam_instance_profile" "custom_worker_group_launch_template_iam_instance_profile" {
+  name  = "${lookup(var.worker_groups_launch_template[count.index], "iam_instance_profile_name", local.workers_group_launch_template_defaults["iam_instance_profile_name"])}"
+  count = "${var.manage_worker_iam_resources ? 0 : var.worker_group_launch_template_count}"
+}

local.tf

@@ -5,6 +5,9 @@ locals {
   # to workaround terraform not supporting short circut evaluation
   cluster_security_group_id = "${coalesce(join("", aws_security_group.cluster.*.id), var.cluster_security_group_id)}"
 
+  cluster_iam_role_name = "${coalesce(join("", aws_iam_role.cluster.*.name), var.cluster_iam_role_name)}"
+  cluster_iam_role_arn  = "${coalesce(join("", aws_iam_role.cluster.*.arn), join("", data.aws_iam_role.custom_cluster_iam_role.*.arn))}"
+
   worker_security_group_id = "${coalesce(join("", aws_security_group.workers.*.id), var.worker_security_group_id)}"
   default_iam_role_id      = "${element(concat(aws_iam_role.workers.*.id, list("")), 0)}"
   kubeconfig_name          = "${var.kubeconfig_name == "" ? "eks_${var.cluster_name}" : var.kubeconfig_name}"
@@ -34,7 +37,8 @@ locals {
     autoscaling_enabled           = false                           # Sets whether policy and matching tags will be added to allow autoscaling.
     additional_security_group_ids = ""                              # A comma delimited list of additional security group ids to include in worker launch config
     protect_from_scale_in         = false                           # Prevent AWS from scaling in, so that cluster-autoscaler is solely responsible.
-    iam_role_id                   = "${local.default_iam_role_id}"  # Use the specified IAM role if set.
+    iam_instance_profile_name     = ""                              # A custom IAM instance profile name. Used when manage_worker_iam_resources is set to false. Incompatible with iam_role_id.
+    iam_role_id                   = "${local.default_iam_role_id}"  # A custom IAM role id. Incompatible with iam_instance_profile_name.
     suspended_processes           = "AZRebalance"                   # A comma delimited string of processes to to suspend. i.e. AZRebalance,HealthCheck,ReplaceUnhealthy
     target_group_arns             = ""                              # A comma delimited list of ALB target group ARNs to be associated to the ASG
     enabled_metrics               = ""                              # A comma delimited list of metrics to be collected i.e. GroupMinSize,GroupMaxSize,GroupDesiredCapacity
@@ -79,7 +83,8 @@ locals {
     autoscaling_enabled                      = false                                         # Sets whether policy and matching tags will be added to allow autoscaling.
     additional_security_group_ids            = ""                                            # A comma delimited list of additional security group ids to include in worker launch config
     protect_from_scale_in                    = false                                         # Prevent AWS from scaling in, so that cluster-autoscaler is solely responsible.
-    iam_role_id                              = "${local.default_iam_role_id}"                # Use the specified IAM role if set.
+    iam_instance_profile_name                = ""                                            # A custom IAM instance profile name. Used when manage_worker_iam_resources is set to false. Incompatible with iam_role_id.
+    iam_role_id                              = "${local.default_iam_role_id}"                # A custom IAM role id. Incompatible with iam_instance_profile_name.
     suspended_processes                      = "AZRebalance"                                 # A comma delimited string of processes to to suspend. i.e. AZRebalance,HealthCheck,ReplaceUnhealthy
     target_group_arns                        = ""                                            # A comma delimited list of ALB target group ARNs to be associated to the ASG
     enabled_metrics                          = ""                                            # A comma delimited list of metrics to be collected i.e. GroupMinSize,GroupMaxSize,GroupDesiredCapacity

outputs.tf

@@ -35,12 +35,12 @@ output "config_map_aws_auth" {
 
 output "cluster_iam_role_name" {
   description = "IAM role name of the EKS cluster."
-  value       = "${aws_iam_role.cluster.name}"
+  value       = "${local.cluster_iam_role_name}"
 }
 
 output "cluster_iam_role_arn" {
   description = "IAM role ARN of the EKS cluster."
-  value       = "${aws_iam_role.cluster.arn}"
+  value       = "${local.cluster_iam_role_arn}"
 }
 
 output "kubeconfig" {
@@ -105,10 +105,10 @@ output "worker_iam_instance_profile_names" {
 
 output "worker_iam_role_name" {
   description = "default IAM role name for EKS worker groups"
-  value       = "${aws_iam_role.workers.name}"
+  value       = "${element(coalescelist(aws_iam_role.workers.*.name, data.aws_iam_instance_profile.custom_worker_group_iam_instance_profile.*.role_name, data.aws_iam_instance_profile.custom_worker_group_launch_template_iam_instance_profile.*.role_name), 0)}"
 }
 
 output "worker_iam_role_arn" {
   description = "default IAM role ARN for EKS worker groups"
-  value       = "${aws_iam_role.workers.arn}"
+  value       = "${element(coalescelist(aws_iam_role.workers.*.arn, data.aws_iam_instance_profile.custom_worker_group_iam_instance_profile.*.role_arn, data.aws_iam_instance_profile.custom_worker_group_launch_template_iam_instance_profile.*.role_arn), 0)}"
 }

variables.tf

@@ -257,3 +257,18 @@ variable "cluster_endpoint_public_access" {
   description = "Indicates whether or not the Amazon EKS public API server endpoint is enabled."
   default     = true
 }
+
+variable "manage_cluster_iam_resources" {
+  description = "Whether to let the module manage cluster IAM resources. If set to false, cluster_iam_role_name must be specified."
+  default     = true
+}
+
+variable "cluster_iam_role_name" {
+  description = "IAM role name for the cluster. Only applicable if manage_cluster_iam_resources is set to false."
+  default     = ""
+}
+
+variable "manage_worker_iam_resources" {
+  description = "Whether to let the module manage worker IAM resources. If set to false, iam_instance_profile_name must be specified for workers."
+  default     = true
+}

workers.tf

@@ -38,7 +38,7 @@ resource "aws_launch_configuration" "workers" {
   name_prefix                 = "${aws_eks_cluster.this.name}-${lookup(var.worker_groups[count.index], "name", count.index)}"
   associate_public_ip_address = "${lookup(var.worker_groups[count.index], "public_ip", local.workers_group_defaults["public_ip"])}"
   security_groups             = ["${local.worker_security_group_id}", "${var.worker_additional_security_group_ids}", "${compact(split(",",lookup(var.worker_groups[count.index],"additional_security_group_ids", local.workers_group_defaults["additional_security_group_ids"])))}"]
-  iam_instance_profile        = "${element(aws_iam_instance_profile.workers.*.id, count.index)}"
+  iam_instance_profile        = "${element(coalescelist(aws_iam_instance_profile.workers.*.id, data.aws_iam_instance_profile.custom_worker_group_iam_instance_profile.*.name), count.index)}"
   image_id                    = "${lookup(var.worker_groups[count.index], "ami_id", local.workers_group_defaults["ami_id"])}"
   instance_type               = "${lookup(var.worker_groups[count.index], "instance_type", local.workers_group_defaults["instance_type"])}"
   key_name                    = "${lookup(var.worker_groups[count.index], "key_name", local.workers_group_defaults["key_name"])}"
@@ -131,32 +131,36 @@ resource "aws_iam_role" "workers" {
   permissions_boundary  = "${var.permissions_boundary}"
   path                  = "${var.iam_path}"
   force_detach_policies = true
+  count                 = "${var.manage_worker_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_instance_profile" "workers" {
   name_prefix = "${aws_eks_cluster.this.name}"
   role        = "${lookup(var.worker_groups[count.index], "iam_role_id",  lookup(local.workers_group_defaults, "iam_role_id"))}"
-  count       = "${var.worker_group_count}"
+  count       = "${var.manage_worker_iam_resources ? var.worker_group_count : 0}"
   path        = "${var.iam_path}"
 }
 
 resource "aws_iam_role_policy_attachment" "workers_AmazonEKSWorkerNodePolicy" {
   policy_arn = "arn:aws:iam::aws:policy/AmazonEKSWorkerNodePolicy"
   role       = "${aws_iam_role.workers.name}"
+  count      = "${var.manage_worker_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_role_policy_attachment" "workers_AmazonEKS_CNI_Policy" {
   policy_arn = "arn:aws:iam::aws:policy/AmazonEKS_CNI_Policy"
   role       = "${aws_iam_role.workers.name}"
+  count      = "${var.manage_worker_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_role_policy_attachment" "workers_AmazonEC2ContainerRegistryReadOnly" {
   policy_arn = "arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly"
   role       = "${aws_iam_role.workers.name}"
+  count      = "${var.manage_worker_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_role_policy_attachment" "workers_additional_policies" {
-  count      = "${var.workers_additional_policies_count}"
+  count      = "${var.manage_worker_iam_resources ? var.workers_additional_policies_count : 0}"
   role       = "${aws_iam_role.workers.name}"
   policy_arn = "${var.workers_additional_policies[count.index]}"
 }
@@ -174,13 +178,15 @@ resource "null_resource" "tags_as_list_of_maps" {
 resource "aws_iam_role_policy_attachment" "workers_autoscaling" {
   policy_arn = "${aws_iam_policy.worker_autoscaling.arn}"
   role       = "${aws_iam_role.workers.name}"
+  count      = "${var.manage_worker_iam_resources ? 1 : 0}"
 }
 
 resource "aws_iam_policy" "worker_autoscaling" {
   name_prefix = "eks-worker-autoscaling-${aws_eks_cluster.this.name}"
   description = "EKS worker node autoscaling policy for cluster ${aws_eks_cluster.this.name}"
   policy      = "${data.aws_iam_policy_document.worker_autoscaling.json}"
   path        = "${var.iam_path}"
+  count       = "${var.manage_worker_iam_resources ? 1 : 0}"
 }
 
 data "aws_iam_policy_document" "worker_autoscaling" {

workers_launch_template.tf

@@ -75,7 +75,7 @@ resource "aws_launch_template" "workers_launch_template" {
   }
 
   iam_instance_profile {
-    name = "${element(aws_iam_instance_profile.workers_launch_template.*.name, count.index)}"
+    name = "${element(coalescelist(aws_iam_instance_profile.workers_launch_template.*.name, data.aws_iam_instance_profile.custom_worker_group_launch_template_iam_instance_profile.*.name), count.index)}"
   }
 
   image_id      = "${lookup(var.worker_groups_launch_template[count.index], "ami_id", local.workers_group_launch_template_defaults["ami_id"])}"
@@ -118,6 +118,6 @@ resource "aws_launch_template" "workers_launch_template" {
 resource "aws_iam_instance_profile" "workers_launch_template" {
   name_prefix = "${aws_eks_cluster.this.name}"
   role        = "${lookup(var.worker_groups_launch_template[count.index], "iam_role_id",  lookup(local.workers_group_launch_template_defaults, "iam_role_id"))}"
-  count       = "${var.worker_group_launch_template_count}"
+  count       = "${var.manage_worker_iam_resources ? var.worker_group_launch_template_count : 0}"
   path        = "${var.iam_path}"
 }