Allow enabling cloudwatch auto scaling group metrics collection for H…

…A mode

README.md

@@ -22,6 +22,7 @@ module "fck-nat" {
   vpc_id               = "vpc-abc1234"
   subnet_id            = "subnet-abc1234"
   # ha_mode              = true                 # Enables high-availability mode
+  # ha_mode_enabled_metrics = ["GroupInServiceInstances"] # Enables specified Cloudwatch metrics collection for high-availability mode
   # eip_allocation_ids   = ["eipalloc-abc1234"] # Allocation ID of an existing EIP
   # use_cloudwatch_agent = true                 # Enables Cloudwatch agent and have metrics reported
 
@@ -78,6 +79,7 @@ module "fck-nat" {
 | <a name="input_eip_allocation_ids"></a> [eip\_allocation\_ids](#input\_eip\_allocation\_ids) | EIP allocation IDs to use for the NAT instance. Automatically assign a public IP if none is provided. Note: Currently only supports at most one EIP allocation. | `list(string)` | `[]` | no |
 | <a name="input_encryption"></a> [encryption](#input\_encryption) | Whether or not to encrypt the EBS volume | `bool` | `true` | no |
 | <a name="input_ha_mode"></a> [ha\_mode](#input\_ha\_mode) | Whether or not high-availability mode should be enabled via autoscaling group | `bool` | `true` | no |
+| <a name="input_ha_mode_enabled_metrics"></a> [ha\_mode\_enabled\_metrics](#input\_ha\_mode\_enabled\_metrics) | Whether or not to enable autoscaling group cloudwatch metrics collection for specified metrics. Disabled by default or when no metrics were provided | `list(string)` | `[]` | no |
 | <a name="input_instance_type"></a> [instance\_type](#input\_instance\_type) | Instance type to use for the NAT instance | `string` | `"t4g.micro"` | no |
 | <a name="input_kms_key_id"></a> [kms\_key\_id](#input\_kms\_key\_id) | Will use the provided KMS key ID to encrypt the EBS volume. Uses the default KMS key if none provided | `string` | `null` | no |
 | <a name="input_name"></a> [name](#input\_name) | Name used for resources created within the module | `string` | n/a | yes |

asg.tf

@@ -1,3 +1,7 @@
+locals {
+  asg_cw_metrics_enabled = length(var.ha_mode_enabled_metrics) >= 1
+}
+
 resource "aws_autoscaling_group" "main" {
   count = var.ha_mode ? 1 : 0
 
@@ -8,6 +12,8 @@ resource "aws_autoscaling_group" "main" {
   health_check_type   = "EC2"
   vpc_zone_identifier = [var.subnet_id]
 
+  enabled_metrics = local.asg_cw_metrics_enabled ? var.ha_mode_enabled_metrics : null
+
   launch_template {
     id      = aws_launch_template.main.id
     version = "$Latest"

docs/header.md

@@ -22,6 +22,7 @@ module "fck-nat" {
   vpc_id               = "vpc-abc1234"
   subnet_id            = "subnet-abc1234"
   # ha_mode              = true                 # Enables high-availability mode
+  # ha_mode_enabled_metrics = ["GroupInServiceInstances"] # Enables specified Cloudwatch metrics collection for high-availability mode
   # eip_allocation_ids   = ["eipalloc-abc1234"] # Allocation ID of an existing EIP
   # use_cloudwatch_agent = true                 # Enables Cloudwatch agent and have metrics reported
 

examples/full/main.tf

@@ -12,6 +12,9 @@ module "fck-nat" {
   vpc_id    = aws_vpc.main.id
   subnet_id = aws_subnet.public.id
   ha_mode   = true
+  ha_mode_enabled_metrics = [
+    "GroupInServiceInstances"
+  ]
 
   update_route_tables = true
   route_tables_ids = {

variables.tf

@@ -55,6 +55,12 @@ variable "ha_mode" {
   default     = true
 }
 
+variable "ha_mode_enabled_metrics" {
+  description = "Whether or not to enable autoscaling group cloudwatch metrics collection for specified metrics. Disabled by default or when no metrics were provided"
+  type = list(string)
+  default = []
+}
+
 variable "instance_type" {
   description = "Instance type to use for the NAT instance"
   type        = string