Enable EKS Kubernetes support for VPC module

.gitignore

+.DS_Store
+.terraform/

.gitlab-ci.yml

 image: alpine:latest
 
 variables:
-  TERRAFORM_URL: "https://releases.hashicorp.com/terraform/0.7.1/terraform_0.7.1_linux_amd64.zip"
+  TERRAFORM_URL: "https://releases.hashicorp.com/terraform/0.11.7/terraform_0.11.7_linux_amd64.zip"
 
 before_script:
   - apk update && apk add ca-certificates && update-ca-certificates && apk add openssl
   - wget -O /tmp/terraform.zip $TERRAFORM_URL
-  - unzip /tmp/terraform.zip -d /usr/local/bin 
+  - unzip /tmp/terraform.zip -d /usr/local/bin
 
 test:
-  script: terraform validate
+  script: terraform init && terraform validate -check-variables=false

main.tf

-variable "name" { 
+variable "name" {
   description = "Name of the VPC"
 }
 
-variable "cidr" { 
+variable "cidr" {
   description = "The CIDR block for the VPC"
 }
 
-variable "availability_zones" { 
+variable "availability_zones" {
   description = "List of availability zones"
   type        = "list"
 }
 
-variable "public_subnets" { 
-  description = "List of public subnets to availability zones" 
+variable "public_subnets" {
+  description = "List of public subnets to availability zones"
   type        = "list"
 }
 
 variable "private_subnets" {
-  description = "List of private subnets to availability zones" 
+  description = "List of private subnets to availability zones"
   type        = "list"
 }
 
-variable "enable_dns_hostnames" { 
+variable "enable_dns_hostnames" {
   description = "When set to true, instances in the VPC get DNS hostname"
   default     = true
 }
 
-variable "enable_dns_support" { 
+variable "enable_dns_support" {
   description = "When set to true, the Amazon DNS server is enabled within the VPC"
   default     = true
 }
 
+variable "enable_eks_support" {
+  description = "When set to true, properly tags VPC assets with proper discovery assets"
+  default     = "true"
+}
+
+variable "eks_cluster_name" {
+  description = "Name of the EKS cluster to reside within the VPC"
+}
+
 resource "aws_vpc" "mod" {
   cidr_block           = "${var.cidr}"
   enable_dns_hostnames = "${var.enable_dns_hostnames}"
   enable_dns_support   = "${var.enable_dns_support}"
 
-  tags { 
-    Name = "${var.name}"
-  }
+  tags = "${var.enable_eks_support == "true" ?
+    map(
+      "Name", "${var.name}",
+      "kubernetes.io/cluster/${var.eks_cluster_name}", "shared",
+    ) :
+    map(
+      "Name", "${var.name}",
+    )
+  }"
 }
 
 resource "aws_subnet" "public" {
-  lifecycle { create_before_destroy = true }
+  lifecycle {
+    create_before_destroy = true
+  }
 
   vpc_id                  = "${aws_vpc.mod.id}"
   cidr_block              = "${element(var.public_subnets, count.index)}"
@@ -56,16 +73,24 @@ resource "aws_subnet" "public" {
 }
 
 resource "aws_subnet" "private" {
-  lifecycle { create_before_destroy = true }
+  lifecycle {
+    create_before_destroy = true
+  }
 
   vpc_id            = "${aws_vpc.mod.id}"
   cidr_block        = "${element(var.private_subnets, count.index)}"
   availability_zone = "${element(var.availability_zones, count.index)}"
   count             = "${length(var.private_subnets)}"
-  
-  tags {
-    Name = "${var.name}.private.${element(var.availability_zones, count.index)}"
-  }
+
+  tags = "${var.enable_eks_support == "true" ?
+    map(
+      "Name", "${var.name}.private.${element(var.availability_zones, count.index)}",
+      "kubernetes.io/cluster/${var.eks_cluster_name}", "shared",
+    ) :
+    map(
+      "Name", "${var.name}.private.${element(var.availability_zones, count.index)}",
+    )
+  }"
 }
 
 resource "aws_internet_gateway" "mod" {
@@ -91,8 +116,8 @@ resource "aws_nat_gateway" "nat" {
 resource "aws_route_table" "public" {
   vpc_id = "${aws_vpc.mod.id}"
 
-  tags { 
-    Name = "${var.name}.public" 
+  tags {
+    Name = "${var.name}.public"
   }
 }
 
@@ -117,7 +142,7 @@ resource "aws_route" "nat_gateway" {
   nat_gateway_id         = "${element(aws_nat_gateway.nat.*.id, count.index)}"
   count                  = "${length(var.public_subnets)}"
 
-  depends_on             = ["aws_route_table.private"]
+  depends_on = ["aws_route_table.private"]
 }
 
 resource "aws_route_table_association" "public" {