Add target_group_arns to worker ASG (#167)

* add target_group_arns to worker default

* add to changelog

CHANGELOG.md

@@ -10,6 +10,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 - `suspended_processes` to `worker_groups` input (by @bkmeneguello)
+- `target_group_arns` to `worker_groups` input (by @zihaoyu)
 
 ### Changed
 

local.tf

@@ -30,10 +30,11 @@ locals {
     kubelet_extra_args            = ""                              # This string is passed directly to kubelet if set. Useful for adding labels or taints.
     subnets                       = "${join(",", var.subnets)}"     # A comma delimited string of subnets to place the worker nodes in. i.e. subnet-123,subnet-456,subnet-789
     autoscaling_enabled           = false                           # Sets whether policy and matching tags will be added to allow autoscaling.
-    additional_security_group_ids = ""                              # A comman delimited list of additional security group ids to include in worker launch config
+    additional_security_group_ids = ""                              # A comma delimited list of additional security group ids to include in worker launch config
     protect_from_scale_in         = false                           # Prevent AWS from scaling in, so that cluster-autoscaler is solely responsible.
     iam_role_id                   = "${local.default_iam_role_id}"  # Use the specified IAM role if set.
     suspended_processes           = ""                              # 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
   }
 
   workers_group_defaults = "${merge(local.workers_group_defaults_defaults, var.workers_group_defaults)}"

workers.tf

@@ -3,6 +3,7 @@ resource "aws_autoscaling_group" "workers" {
   desired_capacity      = "${lookup(var.worker_groups[count.index], "asg_desired_capacity", local.workers_group_defaults["asg_desired_capacity"])}"
   max_size              = "${lookup(var.worker_groups[count.index], "asg_max_size", local.workers_group_defaults["asg_max_size"])}"
   min_size              = "${lookup(var.worker_groups[count.index], "asg_min_size", local.workers_group_defaults["asg_min_size"])}"
+  target_group_arns     = ["${compact(split(",", coalesce(lookup(var.worker_groups[count.index], "target_group_arns", ""), local.workers_group_defaults["target_group_arns"])))}"]
   launch_configuration  = "${element(aws_launch_configuration.workers.*.id, count.index)}"
   vpc_zone_identifier   = ["${split(",", coalesce(lookup(var.worker_groups[count.index], "subnets", ""), local.workers_group_defaults["subnets"]))}"]
   protect_from_scale_in = "${lookup(var.worker_groups[count.index], "protect_from_scale_in", local.workers_group_defaults["protect_from_scale_in"])}"