How to Import an AWS Load Balancer Listener Rule into Terraform

Import AWS Load Balancer Listener Rule with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Elastic Load Balancing resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live AWS Load Balancer Listener Rule 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_lb_listener_rule.api
  id = "arn:aws:elasticloadbalancing:us-east-1:123456789012:listener-rule/app/web/0a1b/0c2d/0e3f"
}

Example aws_lb_listener_rule configuration

Here is a realistic AWS Load Balancer Listener Rule block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "aws_lb_listener_rule" "api" {
  listener_arn = "arn:aws:elasticloadbalancing:us-east-1:123456789012:listener/app/web/0a1b/0c2d"
  priority     = 100

  action {
    type             = "forward"
    target_group_arn = "arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/api/0a1b2c3d"
  }

  condition {
    path_pattern {
      values = ["/api/*"]
    }
  }
}

Gotchas when importing a AWS Load Balancer Listener Rule

• Import by the full listener-rule ARN, not the listener ARN; note the ARN contains an extra ID segment beyond the listener.
• priority must be unique within the listener; the default rule has no priority and is managed through the aws_lb_listener default_action, not here.
• Rules are separate from the parent aws_lb_listener and the aws_lb_target_group they forward to; import each piece you manage.
• Every rule needs at least one condition and one action; an empty rule is invalid and will fail to apply after import.

Doing it manually with terraform import

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