This module will manage a Transit Gateway, as well as its Route Tables, Routes, VPC attachments, Route Table associations and propagations, and VPC routes associated with the VPC attachments.

This module includes several submodules for different workflows and use cases.

• cross-account-vpc-attachment: Creates a cross-account Transit Gateway VPC Attachment by managing the invite/accept interaction between two accounts. Requires two providers, one for each account. The providers must be different accounts, and must be using the same region. The Transit Gateway must be shared using the AWS Resource Access Manager.
• cross-region-peering-attachment:: Creates a cross-region Peering Attachment, managing the invite/accept workflow between the two regions. Requires two providers, one for each region. The providers may be the same or different account, but must be different regions.
• peering-accepter: Accepts a peering attachment request. Used by the cross-region-peering-attachment module.
• peering-attachment: Sends a peering attachment invite. Used by the cross-region-peering-attachment module.
• route: Creates a Transit Gateway Route.
• route-table: Creates a Transit Gateway Route Table.
• vpc-accepter: Accepts a VPC attachment request. Used by the cross-account-vpc-attachment module. Will also the create Transit Gateway Route Table association and propagations for the attachment, and will manage VPC routes associated with the attachment.
• vpc-attachment: Sends a VPC attachment invite. Used by the cross-account-vpc-attachment module. Will also the create Transit Gateway Route Table association and propagations for the attachment, and will manage VPC routes associated with the attachment.

list(object({
    # name used as for_each key
    name = string
    tags = map(string)
  }))

list(object({
    # name used as for_each key
    name                   = string
    blackhole              = bool
    default_route_table    = bool
    destination_cidr_block = string
    # name from vpc_attachments or id of a pre-existing tgw attachment
    transit_gateway_attachment = string
    # name from route_tables or id of a pre-existing route table
    transit_gateway_route_table = string
  }))

list(object({
    # name used as for_each key
    name                   = string
    subnet_ids             = list(string)
    appliance_mode_support = string
    dns_support            = string
    ipv6_support           = string
    tags                   = map(string)
    vpc_routes = list(object({
      # name is used as for_each key
      name                        = string
      route_table_id              = string
      destination_cidr_block      = string
      destination_ipv6_cidr_block = string
    }))
    transit_gateway_default_route_table_association = bool
    transit_gateway_default_route_table_propagation = bool
    # name from route_tables or id of a pre-existing route table
    transit_gateway_route_table_association = string
    # list of route table names from route_tables or ids of pre-existing route tables
    transit_gateway_route_table_propagations = list(string)
  }))

This module has tests that require multiple providers. In order to simplify the provider config, it assumes you have AWS Profiles named aws and awsalternate. These profiles should resolve a credential for two different accounts.