First

README.md

@@ -1 +1,7 @@
-# terraform-aws-scalr_dynamic_vpc_dns
+# scalr_dynamic_vpc_dns module
+
+Manages a VPC and dynamically created subnets in AWS.
+
+1. VPC has DNS enabled
+2. Subnets created dynamically based on max_subnets setting with VPC CIDR broken up evenly into CIDRs for the subnet.
+3. Optional to make the subnets public

main.tf

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+# scalr-vpc-dns
+#
+# Manages a DNS enabled VPC with subnets in every AZ of the region
+
+resource "aws_vpc" "scalr_vpc_dns" {
+  cidr_block              = var.cidr
+  enable_dns_support      = true
+  enable_dns_hostnames    = true
+
+  tags = {
+    Name = "${var.prefix}-scalr-vpc"
+  }
+}
+
+data "aws_availability_zones" "azs" {
+  state = "available"
+}
+
+locals {
+  subnets = var.max_subnets > 0 && var.max_subnets <= length(data.aws_availability_zones.azs.zone_ids) ? var.max_subnets : length(data.aws_availability_zones.azs.zone_ids) 
+}
+
+resource "aws_subnet" "scalr_subnet" {
+  count        = local.subnets
+    vpc_id                  = aws_vpc.scalr_vpc_dns.id
+    availability_zone_id    = element(data.aws_availability_zones.azs.zone_ids,count.index)
+    cidr_block = cidrsubnet(
+                      aws_vpc.scalr_vpc_dns.cidr_block,
+                      ceil(log(local.subnets * 2, 2)),
+                      count.index
+                 )
+    map_public_ip_on_launch = var.public
+
+    tags = {
+      Name = "${var.prefix}-scalr-subnet-${count.index}"
+    }
+
+}

outputs.tf

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+output subnet_ids {
+  value = aws_subnet.scalr_subnet.*.id
+}
+
+output subnet_cidrs {
+  value = aws_subnet.scalr_subnet.*.cidr_block
+}
+
+output vpc_id {
+  value = aws_vpc.scalr_vpc_dns.id
+}

variables.tf

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+variable cidr {
+  description = "CIDR blockfor the VPC in format n.n.n.n/n. Subnet CIDR's will be generated to splut this range evenly across the subnets"
+}
+
+variable prefix {
+ description = "Prefic for resource names"
+}
+
+variable public {
+  description = "Indicates if public IP's should be allocated to instances on launched in the VPC"
+  type        = bool
+}
+
+variable max_subnets {
+  description = "Maximum number of subnets to create. Must be <= number of AZs (-1 = all AZs)"
+  default     = -1
+}