How to Import an AWS Route Table Association into Terraform

Import AWS Route Table Association with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Amazon VPC resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live AWS Route Table Association 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_route_table_association.public_a
  id = "subnet-0aa1b2c3d4e5f6a7b/rtb-0a1b2c3d4e5f6a7b8"
}

Example aws_route_table_association configuration

Here is a realistic AWS Route Table Association block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "aws_route_table_association" "public_a" {
  subnet_id      = "subnet-0aa1b2c3d4e5f6a7b"
  route_table_id = "rtb-0a1b2c3d4e5f6a7b8"
}

Gotchas when importing a AWS Route Table Association

• The import ID is SUBNET-ID/ROUTE-TABLE-ID for a subnet association, or GATEWAY-ID/ROUTE-TABLE-ID for a gateway (edge) association.
• This association is a separate resource from aws_route_table; importing the route table does not import its associations.
• A subnet can be associated with only one route table at a time; importing an association that conflicts with the implicit main-table link is expected and replaces it.
• The implicit association to the VPC main route table is not a real resource and cannot be imported; manage it with aws_main_route_table_association instead.

Doing it manually with terraform import

The native approach is to write the aws_route_table_association block by hand, then run terraform import aws_route_table_association.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