Add support for DHCP options set (terraform-aws-modules#20)

* Add support for DHCP options set

* code cleanup

* remove unnecessary depends_on in aws_vpc_dhcp_options_association definition

Author: bcenker

README.md

@@ -14,7 +14,8 @@ These types of resources are supported:
 * [VPN Gateway](https://www.terraform.io/docs/providers/aws/r/vpn_gateway.html)
 * [VPC Endpoint](https://www.terraform.io/docs/providers/aws/r/vpc_endpoint.html) (S3 and DynamoDB)
 * [RDS DB Subnet Group](https://www.terraform.io/docs/providers/aws/r/db_subnet_group.html) 
-* [ElastiCache Subnet Group](https://www.terraform.io/docs/providers/aws/r/elasticache_subnet_group.html) 
+* [ElastiCache Subnet Group](https://www.terraform.io/docs/providers/aws/r/elasticache_subnet_group.html)
+* [DHCP Options Set](https://www.terraform.io/docs/providers/aws/r/vpc_dhcp_options.html)
 
 Usage
 -----

examples/complete-vpc/main.tf

@@ -19,6 +19,10 @@ module "vpc" {
   enable_s3_endpoint       = true
   enable_dynamodb_endpoint = true
 
+  enable_dhcp_options              = true
+  dhcp_options_domain_name         = "service.consul"
+  dhcp_options_domain_name_servers = ["127.0.0.1", "10.10.0.2"]
+
   tags = {
     Owner       = "user"
     Environment = "staging"

main.tf

@@ -10,6 +10,29 @@ resource "aws_vpc" "this" {
   tags = "${merge(var.tags, map("Name", format("%s", var.name)))}"
 }
 
+###################
+# DHCP Options Set
+###################
+resource "aws_vpc_dhcp_options" "this" {
+  count = "${var.enable_dhcp_options ? 1 : 0}"
+
+  domain_name          = "${var.dhcp_options_domain_name}"
+  domain_name_servers  = "${var.dhcp_options_domain_name_servers}"
+  ntp_servers          = "${var.dhcp_options_ntp_servers}"
+  netbios_name_servers = "${var.dhcp_options_netbios_name_servers}"
+  netbios_node_type    = "${var.dhcp_options_netbios_node_type}"
+}
+
+###############################
+# DHCP Options Set Association
+###############################
+resource "aws_vpc_dhcp_options_association" "this" {
+  count = "${var.enable_dhcp_options ? 1 : 0}"
+
+  vpc_id          = "${aws_vpc.this.id}"
+  dhcp_options_id = "${aws_vpc_dhcp_options.this.id}"
+}
+
 ###################
 # Internet Gateway
 ###################

variables.tf

@@ -129,3 +129,36 @@ variable "elasticache_subnet_tags" {
   description = "Additional tags for the elasticache subnets"
   default     = {}
 }
+
+variable "enable_dhcp_options" {
+  description = "Should be true if you want to specify a DHCP options set with a custom domain name, DNS servers, NTP servers, netbios servers, and/or netbios server type"
+  default     = false
+}
+
+variable "dhcp_options_domain_name" {
+  description = "Specifies DNS name for DHCP options set"
+  default     = ""
+}
+
+variable "dhcp_options_domain_name_servers" {
+  description = "Specify a list of DNS server addresses for DHCP options set, default to AWS provided"
+  type        = "list"
+  default     = ["AmazonProvidedDNS"]
+}
+
+variable "dhcp_options_ntp_servers" {
+  description = "Specify a list of NTP servers for DHCP options set"
+  type        = "list"
+  default     = []
+}
+
+variable "dhcp_options_netbios_name_servers" {
+  description = "Specify a list of netbios servers for DHCP options set"
+  type        = "list"
+  default     = []
+}
+
+variable "dhcp_options_netbios_node_type" {
+  description = "Specify netbios node_type for DHCP options set"
+  default     = ""
+}