feat: Add supprot for creating placement group for managed node group (#2959)

Co-authored-by: Bryant Biggs <[email protected]>

Author: james-masson

modules/eks-managed-node-group/README.md

@@ -120,6 +120,7 @@ module "eks_managed_node_group" {
 | <a name="input_create"></a> [create](#input\_create) | Determines whether to create EKS managed node group or not | `bool` | `true` | no |
 | <a name="input_create_iam_role"></a> [create\_iam\_role](#input\_create\_iam\_role) | Determines whether an IAM role is created or to use an existing IAM role | `bool` | `true` | no |
 | <a name="input_create_launch_template"></a> [create\_launch\_template](#input\_create\_launch\_template) | Determines whether to create a launch template or not. If set to `false`, EKS will use its own default launch template | `bool` | `true` | no |
+| <a name="input_create_placement_group"></a> [create\_placement\_group](#input\_create\_placement\_group) | Determines whether a placement group is created & used by the nodegroup | `bool` | `false` | no |
 | <a name="input_create_schedule"></a> [create\_schedule](#input\_create\_schedule) | Determines whether to create autoscaling group schedule or not | `bool` | `true` | no |
 | <a name="input_credit_specification"></a> [credit\_specification](#input\_credit\_specification) | Customize the credit specification of the instance | `map(string)` | `{}` | no |
 | <a name="input_desired_size"></a> [desired\_size](#input\_desired\_size) | Desired number of instances/nodes | `number` | `1` | no |
@@ -162,6 +163,7 @@ module "eks_managed_node_group" {
 | <a name="input_name"></a> [name](#input\_name) | Name of the EKS managed node group | `string` | `""` | no |
 | <a name="input_network_interfaces"></a> [network\_interfaces](#input\_network\_interfaces) | Customize network interfaces to be attached at instance boot time | `list(any)` | `[]` | no |
 | <a name="input_placement"></a> [placement](#input\_placement) | The placement of the instance | `map(string)` | `{}` | no |
+| <a name="input_placement_group_strategy"></a> [placement\_group\_strategy](#input\_placement\_group\_strategy) | The placement group strategy | `string` | `"cluster"` | no |
 | <a name="input_platform"></a> [platform](#input\_platform) | Identifies if the OS platform is `bottlerocket` or `linux` based; `windows` is not supported | `string` | `"linux"` | no |
 | <a name="input_post_bootstrap_user_data"></a> [post\_bootstrap\_user\_data](#input\_post\_bootstrap\_user\_data) | User data that is appended to the user data script after of the EKS bootstrap script. Not used when `platform` = `bottlerocket` | `string` | `""` | no |
 | <a name="input_pre_bootstrap_user_data"></a> [pre\_bootstrap\_user\_data](#input\_pre\_bootstrap\_user\_data) | User data that is injected into the user data script ahead of the EKS bootstrap script. Not used when `platform` = `bottlerocket` | `string` | `""` | no |

modules/eks-managed-node-group/main.tf

@@ -60,7 +60,7 @@ locals {
   launch_template_name = coalesce(var.launch_template_name, "${var.name}-eks-node-group")
   security_group_ids   = compact(concat([var.cluster_primary_security_group_id], var.vpc_security_group_ids))
 
-  placement = var.create && var.enable_efa_support ? { group_name = aws_placement_group.this[0].name } : var.placement
+  placement = var.create && (var.enable_efa_support || var.create_placement_group) ? { group_name = aws_placement_group.this[0].name } : var.placement
 }
 
 resource "aws_launch_template" "this" {
@@ -526,10 +526,10 @@ resource "aws_iam_role_policy_attachment" "additional" {
 ################################################################################
 
 resource "aws_placement_group" "this" {
-  count = var.create && var.enable_efa_support ? 1 : 0
+  count = var.create && (var.enable_efa_support || var.create_placement_group) ? 1 : 0
 
   name     = "${var.cluster_name}-${var.name}"
-  strategy = "cluster"
+  strategy = var.placement_group_strategy
 
   tags = var.tags
 }

modules/eks-managed-node-group/variables.tf

@@ -276,6 +276,18 @@ variable "placement" {
   default     = {}
 }
 
+variable "create_placement_group" {
+  description = "Determines whether a placement group is created & used by the nodegroup"
+  type        = bool
+  default     = false
+}
+
+variable "placement_group_strategy" {
+  description = "The placement group strategy"
+  type        = string
+  default     = "cluster"
+}
+
 variable "private_dns_name_options" {
   description = "The options for the instance hostname. The default values are inherited from the subnet"
   type        = map(string)

node_groups.tf

@@ -369,6 +369,8 @@ module "eks_managed_node_group" {
   metadata_options                   = try(each.value.metadata_options, var.eks_managed_node_group_defaults.metadata_options, local.metadata_options)
   enable_monitoring                  = try(each.value.enable_monitoring, var.eks_managed_node_group_defaults.enable_monitoring, true)
   enable_efa_support                 = try(each.value.enable_efa_support, var.eks_managed_node_group_defaults.enable_efa_support, false)
+  create_placement_group             = try(each.value.create_placement_group, var.eks_managed_node_group_defaults.create_placement_group, false)
+  placement_group_strategy           = try(each.value.placement_group_strategy, var.eks_managed_node_group_defaults.placement_group_strategy, "cluster")
   network_interfaces                 = try(each.value.network_interfaces, var.eks_managed_node_group_defaults.network_interfaces, [])
   placement                          = try(each.value.placement, var.eks_managed_node_group_defaults.placement, {})
   maintenance_options                = try(each.value.maintenance_options, var.eks_managed_node_group_defaults.maintenance_options, {})