Merge pull request #66 from FairwindsOps/nb/single-cluster-optional-subnet

allow admin subnet to be optional

Author: bambash

modules/single-cluster/outputs.tf

@@ -5,3 +5,23 @@ output "provisioned_cidrs" {
     admin_cidr_subnets   = local.admin_cidr_subnets
   }
 }
+
+output "aws_subnet_ids" {
+  value = {
+    "admin"   = aws_subnet.admin.*.id
+    "private" = aws_subnet.private.*.id
+    "public"  = aws_subnet.public.*.id
+  }
+}
+
+output "aws_subnet_admin_ids" {
+  value = [aws_subnet.admin.*.id]
+}
+
+output "aws_subnet_public_ids" {
+  value = [aws_subnet.public.*.id]
+}
+
+output "aws_subnet_private_ids" {
+  value = [aws_subnet.private.*.id]
+}

modules/single-cluster/subnet.tf

@@ -1,24 +1,20 @@
 # Subnet creation
 ## Admin
 resource "aws_subnet" "admin" {
-  count             = local._count_of_availability_zones
+  count             = var.enable_admin_subnet == false ? 0 : local._count_of_availability_zones
   vpc_id            = aws_vpc.kube_vpc.id
   cidr_block        = local.admin_cidr_subnets[count.index]
   availability_zone = local.avail_zones_list[count.index]
   tags = merge(
-    local.tags,
+    local.admin_subnet_tags,
     {
       "Name" = "Admin Subnet"
-    },
+    }
   )
 }
 
-output "aws_subnet_admin_ids" {
-  value = [aws_subnet.admin.*.id]
-}
-
 resource "aws_route_table_association" "admin" {
-  count          = local._count_of_availability_zones
+  count          = var.enable_admin_subnet == false ? 0 : local._count_of_availability_zones
   subnet_id      = element(aws_subnet.admin.*.id, count.index)
   route_table_id = element(aws_route_table.private.*.id, count.index)
 }
@@ -30,17 +26,13 @@ resource "aws_subnet" "public" {
   cidr_block        = local.public_cidr_subnets[count.index]
   availability_zone = local.avail_zones_list[count.index]
   tags = merge(
-    local.tags,
+    local.public_subnet_tags,
     {
       "Name" = "Public Subnet"
-    },
+    }
   )
 }
 
-output "aws_subnet_public_ids" {
-  value = [aws_subnet.public.*.id]
-}
-
 resource "aws_route_table_association" "public" {
   count          = local._count_of_availability_zones
   subnet_id      = element(aws_subnet.public.*.id, count.index)
@@ -54,17 +46,13 @@ resource "aws_subnet" "private" {
   cidr_block        = local.private_cidr_subnets[count.index]
   availability_zone = local.avail_zones_list[count.index]
   tags = merge(
-    local.tags,
+    local.private_subnet_tags,
     {
       "Name" = "Private Subnet"
-    },
+    }
   )
 }
 
-output "aws_subnet_private_ids" {
-  value = [aws_subnet.private.*.id]
-}
-
 resource "aws_route_table_association" "private" {
   count          = local._count_of_availability_zones
   subnet_id      = element(aws_subnet.private.*.id, count.index)

modules/single-cluster/variables.tf

@@ -16,6 +16,13 @@ variable "private_subnets_list" {
 variable "admin_subnets_list" {
   type        = list(string)
   description = "A list of the subnets to create for admin subnets"
+  default     = null
+}
+
+variable "enable_admin_subnet" {
+  type        = bool
+  description = "A true/false value to enable the admin subnets"
+  default     = true
 }
 
 variable "vpc_name" {
@@ -45,7 +52,28 @@ variable "vpc_enable_classiclink" {
 }
 
 ## Tagging Settings
-variable "extra_tags" {
+variable "extra_tags_global" {
+  type        = map(string)
+  description = "Map of tags to apply in addition to already predefined tags of the module."
+  default     = {}
+}
+
+## Tagging Settings
+variable "extra_tags_admin_subnet" {
+  type        = map(string)
+  description = "Map of tags to apply in addition to already predefined tags of the module."
+  default     = {}
+}
+
+## Tagging Settings
+variable "extra_tags_public_subnet" {
+  type        = map(string)
+  description = "Map of tags to apply in addition to already predefined tags of the module."
+  default     = {}
+}
+
+## Tagging Settings
+variable "extra_tags_private_subnet" {
   type        = map(string)
   description = "Map of tags to apply in addition to already predefined tags of the module."
   default     = {}
@@ -58,7 +86,10 @@ locals {
     "Author"     = "Fairwinds"
   }
 
-  tags             = merge(local.default_tags, var.extra_tags)
+  tags             = merge(local.default_tags, var.extra_tags_global)
+  admin_subnet_tags = merge(local.tags, var.extra_tags_admin_subnet)
+  private_subnet_tags = merge(local.tags, var.extra_tags_private_subnet)
+  public_subnet_tags = merge(local.tags, var.extra_tags_public_subnet)
   avail_zones_list = split(",", var.availability_zones)
 }
 
@@ -73,7 +104,7 @@ locals {
   _count_of_availability_zones          = length(local.avail_zones_list)
   _public_subnets_count_minus_az_count  = length(var.public_subnets_list) - local._count_of_availability_zones
   _private_subnets_count_minus_az_count = length(var.private_subnets_list) - local._count_of_availability_zones
-  _admin_subnets_count_minus_az_count   = length(var.admin_subnets_list) - local._count_of_availability_zones
+  _admin_subnets_count_minus_az_count   = var.enable_admin_subnet == false ? 0 : length(var.admin_subnets_list) - local._count_of_availability_zones
 }
 
 resource "null_resource" "validate_public_subnet_count_matches_availability_zone_count" {