How to Import an AWS Transit Gateway Connect Peer into Terraform

Import AWS Transit Gateway Connect Peer with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Amazon VPC Transit Gateway resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live AWS Transit Gateway Connect Peer to managed Terraform.

terraback scan all aws --region us-east-1

terraback aws import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = aws_ec2_transit_gateway_connect_peer.example
  id = "tgw-connect-peer-12345678"
}

Example aws_ec2_transit_gateway_connect_peer configuration

Here is a realistic AWS Transit Gateway Connect Peer block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "aws_ec2_transit_gateway_connect_peer" "example" {
  transit_gateway_attachment_id = "tgw-attach-12345678"
  peer_address                  = "10.1.2.3"
  inside_cidr_blocks            = ["169.254.100.0/29"]

  tags = {
    Name = "example-connect-peer"
  }
}

Gotchas when importing a AWS Transit Gateway Connect Peer

• A Connect Peer is a child of an aws_ec2_transit_gateway_connect attachment; transit_gateway_attachment_id must reference that parent Connect attachment, which has to exist first.
• inside_cidr_blocks must be a /29 from the 169.254.0.0/16 link-local range and is immutable; getting it wrong forces recreation.
• bgp_asn and the BGP session details are established with the on-premises appliance at peer_address; importing only captures Terraform state, not the live BGP status, which you must verify separately.
• peer_address, inside_cidr_blocks, and transit_gateway_attachment_id are all force-new; any edit after import destroys and recreates the peer, dropping the GRE tunnel.

Doing it manually with terraform import

The native approach is to write the aws_ec2_transit_gateway_connect_peer block by hand, then run terraform import aws_ec2_transit_gateway_connect_peer.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other AWS resources