AWS Transit Gateway Terraform module

Terraform module which creates Transit Gateway resources on AWS.

This type of resources are supported:

• Transit Gateway
• Transit Gateway Route
• Transit Gateway Route Table
• Transit Gateway Route Table Association
• Transit Gateway Route Table Propagation
• Transit Gateway VPC Attachment

Not supported yet:

• Transit Gateway VPC Attachment Accepter

Terraform versions

Only Terraform 0.12 or newer is supported.

Usage with VPC module

module "tgw" {
  source  = "terraform-aws-modules/transit-gateway/aws"
  version = "~> 1.0"
  
  name        = "my-tgw"
  description = "My TGW shared with several other AWS accounts"
  
  enable_auto_accept_shared_attachments = true

  vpc_attachments = {
    vpc = {
      vpc_id       = module.vpc.vpc_id
      subnet_ids   = module.vpc.private_subnets
      dns_support  = true
      ipv6_support = true

      tgw_routes = [
        {
          destination_cidr_block = "30.0.0.0/16"
        },
        {
          blackhole = true
          destination_cidr_block = "40.0.0.0/20"
        }
      ]
    }
  }

  ram_allow_external_principals = true
  ram_principals = [307990089504]

  tags = {
    Purpose = "tgw-complete-example"
  }
}

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "~> 2.0"

  name = "my-vpc"

  cidr = "10.10.0.0/16"

  azs             = ["eu-west-1a", "eu-west-1b", "eu-west-1c"]
  private_subnets = ["10.10.1.0/24", "10.10.2.0/24", "10.10.3.0/24"]

  enable_ipv6                                    = true
  private_subnet_assign_ipv6_address_on_creation = true
  private_subnet_ipv6_prefixes                   = [0, 1, 2]
}

Examples

• Complete example shows TGW in combination with the VPC module and Resource Access Manager (RAM).
• Multi-account example shows TGW resources shared with different AWS accounts (via Resource Access Manager (RAM)).

Requirements

Name	Version
terraform	>= 0.12.7, < 0.14
aws	>= 2.24, < 4.0

Providers

Name	Version
aws	>= 2.24, < 4.0

Inputs

Name	Description	Type	Default	Required
amazon_side_asn	The Autonomous System Number (ASN) for the Amazon side of the gateway. By default the TGW is created with the current default Amazon ASN.	string	"64512"	no
create_tgw	Controls if TGW should be created (it affects almost all resources)	bool	true	no
description	Description of the EC2 Transit Gateway	string	null	no
enable_auto_accept_shared_attachments	Whether resource attachment requests are automatically accepted	bool	false	no
enable_default_route_table_association	Whether resource attachments are automatically associated with the default association route table	bool	true	no
enable_default_route_table_propagation	Whether resource attachments automatically propagate routes to the default propagation route table	bool	true	no
enable_dns_support	Should be true to enable DNS support in the TGW	bool	true	no
enable_vpn_ecmp_support	Whether VPN Equal Cost Multipath Protocol support is enabled	bool	true	no
name	Name to be used on all the resources as identifier	string	""	no
ram_allow_external_principals	Indicates whether principals outside your organization can be associated with a resource share.	bool	false	no
ram_name	The name of the resource share of TGW	string	""	no
ram_principals	A list of principals to share TGW with. Possible values are an AWS account ID, an AWS Organizations Organization ARN, or an AWS Organizations Organization Unit ARN	list(string)	[]	no
ram_resource_share_arn	ARN of RAM resource share	string	""	no
ram_tags	Additional tags for the RAM	map(string)	{}	no
share_tgw	Whether to share your transit gateway with other accounts	bool	true	no
tags	A map of tags to add to all resources	map(string)	{}	no
tgw_route_table_tags	Additional tags for the TGW route table	map(string)	{}	no
tgw_tags	Additional tags for the TGW	map(string)	{}	no
tgw_vpc_attachment_tags	Additional tags for VPC attachments	map(string)	{}	no
transit_gateway_route_table_id	Identifier of EC2 Transit Gateway Route Table to use with the Target Gateway when reusing it between multiple TGWs	string	null	no
vpc_attachments	Maps of maps of VPC details to attach to TGW. Type 'any' to disable type validation by Terraform.	any	{}	no

Outputs

Name	Description
this_ec2_transit_gateway_arn	EC2 Transit Gateway Amazon Resource Name (ARN)
this_ec2_transit_gateway_association_default_route_table_id	Identifier of the default association route table
this_ec2_transit_gateway_id	EC2 Transit Gateway identifier
this_ec2_transit_gateway_owner_id	Identifier of the AWS account that owns the EC2 Transit Gateway
this_ec2_transit_gateway_propagation_default_route_table_id	Identifier of the default propagation route table
this_ec2_transit_gateway_route_ids	List of EC2 Transit Gateway Route Table identifier combined with destination
this_ec2_transit_gateway_route_table_association	Map of EC2 Transit Gateway Route Table Association attributes
this_ec2_transit_gateway_route_table_association_ids	List of EC2 Transit Gateway Route Table Association identifiers
this_ec2_transit_gateway_route_table_default_association_route_table	Boolean whether this is the default association route table for the EC2 Transit Gateway
this_ec2_transit_gateway_route_table_default_propagation_route_table	Boolean whether this is the default propagation route table for the EC2 Transit Gateway
this_ec2_transit_gateway_route_table_id	EC2 Transit Gateway Route Table identifier
this_ec2_transit_gateway_route_table_propagation	Map of EC2 Transit Gateway Route Table Propagation attributes
this_ec2_transit_gateway_route_table_propagation_ids	List of EC2 Transit Gateway Route Table Propagation identifiers
this_ec2_transit_gateway_vpc_attachment	Map of EC2 Transit Gateway VPC Attachment attributes
this_ec2_transit_gateway_vpc_attachment_ids	List of EC2 Transit Gateway VPC Attachment identifiers
this_ram_principal_association_id	The Amazon Resource Name (ARN) of the Resource Share and the principal, separated by a comma
this_ram_resource_share_id	The Amazon Resource Name (ARN) of the resource share

Authors

Module managed by Anton Babenko.

License

Apache 2 Licensed. See LICENSE for full details.