AWS VPC Module

Creates a VPC in AWS.

The default behavior of this module is to create a both an Internal and External for two Availability Zones for the AWS Region configured on the AWS Provider.

Availability Zones

You can either provide a list of subnets for the Region via the availability_zones input or allow the Module to resolve the list of available zones and specify a count of how many Availability Zones should be used via the availability_zones_count input. The count input is ignored when an explicit list is given.

This module does support Local Zones by setting the allow_local_zones input to true. When using Local Zones, its recommended to pass an explicit list of zones via the availability_zones input.

Subnets

By Default a Public (external) and Private (internal) subnet will be provisioned for each Availability Zone used.

This module allows you to pass in the desired size of the Subnets based on the count of desired IP Addresses. The Subnet sizes are determined via the external_subnets and internal_subnets list inputs. Internally, the size is resolved down to the correct mask and CIDR Range will be produced based off the given VPC CIDR Block.

If you pass a single value in either the list input, that value will be used for all subnets of that type.

It's important that the CIDR Block for the VPC has the address space necessary to support the requested IP Address counts for each subnet.

NAT Gateways

The default behavior is to create a NAT Gateway for each Internal Subnet, to provide egress out to the internet. This behavior can be disabled by passing the use_nat_gateways input as false.

Default Usage

 module "vpc" {
   source = "terra-mod/vpc/aws"

   environment = "production"
   name        = "some-vpc"
   
   cidr = "10.0.0.0/16"
   
   region = "us-west-2"
   
   // you can manually specify subnets, or just use the availability_zone_count
   availability_zone_count = 2
   
   // provision each external subnet with 256 ip addresses (/24)
   external_subnets = [256]
   
   // provision each internal subnet with 256 ip addresses (/24)
   internal_subnets = [256]
   
   // Use NAT Gateways to provide egress to the internet for the Internal subnets
   use_nat_gateways = true
 }

Example with Differing Subnet Sizes

 module "vpc" {
   source = "terra-mod/vpc/aws"

   environment = "production"
   name        = "some-vpc"
   
   cidr = "10.0.0.0/16"
   
   // you can manually specify subnets, or just use the availability_zone_count
   availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]
   
   // provision three external subnets with 256 ip addresses each (/24)
   external_subnets = [256]
   
   // provision one /24 (in us-west-2a) and two /20's (might be useful for EIN heavy services, lambda, fargate, etc)
   internal_subnets = [256, 4096, 4096]
 }