Adding external ENIs

README.md

@@ -280,6 +280,7 @@ Available targets:
 | <a name="input_enabled"></a> [enabled](#input\_enabled) | Set to false to prevent the module from creating any resources | `bool` | `null` | no |
 | <a name="input_environment"></a> [environment](#input\_environment) | ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT' | `string` | `null` | no |
 | <a name="input_evaluation_periods"></a> [evaluation\_periods](#input\_evaluation\_periods) | The number of periods over which data is compared to the specified threshold. | `number` | `5` | no |
+| <a name="input_external_network_interface_enabled"></a> [external\_network\_interface\_enabled](#input\_external\_network\_interface\_enabled) | Wheter to attach an external ENI as the eth0 interface for the instance. Any change to the interface will force instance recreation. | `bool` | `false` | no |
 | <a name="input_id_length_limit"></a> [id\_length\_limit](#input\_id\_length\_limit) | Limit `id` to this many characters (minimum 6).<br>Set to `0` for unlimited length.<br>Set to `null` for keep the existing setting, which defaults to `0`.<br>Does not affect `id_full`. | `number` | `null` | no |
 | <a name="input_instance_initiated_shutdown_behavior"></a> [instance\_initiated\_shutdown\_behavior](#input\_instance\_initiated\_shutdown\_behavior) | Specifies whether an instance stops or terminates when you initiate shutdown from the instance. Can be one of 'stop' or 'terminate'. | `string` | `null` | no |
 | <a name="input_instance_profile"></a> [instance\_profile](#input\_instance\_profile) | A pre-defined profile to attach to the instance (default is to build our own) | `string` | `""` | no |

docs/terraform.md

@@ -83,6 +83,7 @@
 | <a name="input_enabled"></a> [enabled](#input\_enabled) | Set to false to prevent the module from creating any resources | `bool` | `null` | no |
 | <a name="input_environment"></a> [environment](#input\_environment) | ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT' | `string` | `null` | no |
 | <a name="input_evaluation_periods"></a> [evaluation\_periods](#input\_evaluation\_periods) | The number of periods over which data is compared to the specified threshold. | `number` | `5` | no |
+| <a name="input_external_network_interface_enabled"></a> [external\_network\_interface\_enabled](#input\_external\_network\_interface\_enabled) | Wheter to attach an external ENI as the eth0 interface for the instance. Any change to the interface will force instance recreation. | `bool` | `false` | no |
 | <a name="input_id_length_limit"></a> [id\_length\_limit](#input\_id\_length\_limit) | Limit `id` to this many characters (minimum 6).<br>Set to `0` for unlimited length.<br>Set to `null` for keep the existing setting, which defaults to `0`.<br>Does not affect `id_full`. | `number` | `null` | no |
 | <a name="input_instance_initiated_shutdown_behavior"></a> [instance\_initiated\_shutdown\_behavior](#input\_instance\_initiated\_shutdown\_behavior) | Specifies whether an instance stops or terminates when you initiate shutdown from the instance. Can be one of 'stop' or 'terminate'. | `string` | `null` | no |
 | <a name="input_instance_profile"></a> [instance\_profile](#input\_instance\_profile) | A pre-defined profile to attach to the instance (default is to build our own) | `string` | `""` | no |

main.tf

@@ -123,9 +123,9 @@ resource "aws_instance" "default" {
   user_data_base64                     = var.user_data_base64
   iam_instance_profile                 = local.instance_profile
   instance_initiated_shutdown_behavior = var.instance_initiated_shutdown_behavior
-  associate_public_ip_address          = var.associate_public_ip_address
+  associate_public_ip_address          = var.external_network_interface_enabled ? null : var.associate_public_ip_address
   key_name                             = var.ssh_key_pair
-  subnet_id                            = var.subnet
+  subnet_id                            = var.external_network_interface_enabled ? null : var.subnet
   monitoring                           = var.monitoring
   private_ip                           = var.private_ip
   secondary_private_ips                = var.secondary_private_ips
@@ -134,13 +134,23 @@ resource "aws_instance" "default" {
   ipv6_addresses                       = length(var.ipv6_addresses) == 0 ? null : var.ipv6_addresses
   tenancy                              = var.tenancy
 
-  vpc_security_group_ids = compact(
+  vpc_security_group_ids = var.external_network_interface_enabled ? null : compact(
     concat(
       formatlist("%s", module.security_group.id),
       var.security_groups
     )
   )
 
+  dynamic "network_interface" {
+    for_each = var.external_network_interface_enabled ? var.external_network_interfaces : []
+    content {
+      delete_on_termination = each.key.delete_on_termination ? each.key.delete_on_termination : false
+      device_index          = each.key.device_index != 0 ? each.key.device_index : 0
+      network_card_index    = each.key.network_card_index != 0 ? each.key.network_card_index : 0
+      network_interface_id  = each.key.network_interface_id
+    }
+
+  }
   root_block_device {
     volume_type           = local.root_volume_type
     volume_size           = var.root_volume_size

variables.tf

@@ -384,3 +384,20 @@ variable "tenancy" {
     error_message = "Tenancy field can only be one of default, dedicated, host."
   }
 }
+
+variable "external_network_interface_enabled" {
+  type        = bool
+  default     = false
+  description = "Wheter to attach an external ENI as the eth0 interface for the instance. Any change to the interface will force instance recreation."
+}
+
+variable "external_network_interfaces" {
+  type = object({
+    delete_on_termination = bool
+    device_index          = number
+    network_card_index    = number
+    network_interface_id  = string
+  })
+  description = "The external interface definitions to attach to the instances. This depends on the instance type"
+  default     = null
+}