Remove cluster-name tagging from subnets

* These tags were previously required by aws-load-balancer-controller/alb-ingress-controller
* We no longer ship a ingress controller with the module since #225
* aws-load-balancer-controller doesn't need those tags anyway since v2.1.2 - kubernetes-sigs/aws-load-balancer-controller#1773

Author: errm

main.tf

@@ -4,7 +4,6 @@ module "vpc" {
   name               = var.cluster_name
   cidr_block         = var.cidr_block
   availability_zones = var.availability_zones
-  cluster_names      = var.cluster_names
 }
 
 module "iam" {

modules/vpc/subnets.tf

@@ -1,6 +1,5 @@
 locals {
   az_subnet_numbers = zipmap(var.availability_zones, range(0, length(var.availability_zones)))
-  cluster_tags      = { for cluster_name in var.cluster_names : "kubernetes.io/cluster/${cluster_name}" => "shared" }
 }
 
 resource "aws_subnet" "public" {
@@ -11,14 +10,11 @@ resource "aws_subnet" "public" {
   vpc_id                  = aws_vpc.network.id
   map_public_ip_on_launch = true
 
-  tags = merge(
-    local.cluster_tags,
-    {
-      Name                             = "${var.name}-public-${each.key}"
-      "kubernetes.io/role/elb"         = "1"
-      "kubernetes.io/role/alb-ingress" = "1"
-    }
-  )
+  tags = {
+    Name                             = "${var.name}-public-${each.key}"
+    "kubernetes.io/role/elb"         = "1"
+    "kubernetes.io/role/alb-ingress" = "1"
+  }
 }
 
 resource "aws_route_table_association" "public" {

modules/vpc/variables.tf

@@ -11,9 +11,3 @@ variable "cidr_block" {
 variable "availability_zones" {
   description = "The availability zones to create subnets in"
 }
-
-variable "cluster_names" {
-  description = "Names of the EKS clusters deployed in this VPC."
-  type        = list(string)
-  default     = []
-}

variables.tf

@@ -3,11 +3,6 @@ variable "cluster_name" {
   description = "A name for the EKS cluster, and the resources it depends on"
 }
 
-variable "cluster_names" {
-  type        = list(string)
-  description = ""
-}
-
 variable "cidr_block" {
   type        = string
   description = "The CIDR block for the VPC that EKS will run in"