How to Import an AWS ECS Service into Terraform

Import AWS ECS Service with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Amazon ECS resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live AWS ECS Service 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_ecs_service.web
  id = "prod-cluster/web"
}

Example aws_ecs_service configuration

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

resource "aws_ecs_service" "web" {
  name            = "web"
  cluster         = "prod-cluster"
  task_definition = "web:42"
  desired_count   = 3
  launch_type     = "FARGATE"

  network_configuration {
    subnets          = ["subnet-0bb1c79de3a1b2c3d"]
    security_groups  = ["sg-0123456789abcdef0"]
    assign_public_ip = false
  }
}

Gotchas when importing a AWS ECS Service

• The import ID is cluster-name/service-name, not the service ARN.
• task_definition and desired_count drift as deployments happen and the service scales; the generated config commonly ignores changes to both.
• The referenced task definition, cluster, target groups, and security groups are separate resources and are not imported with the service.
• For services using an external deployment controller (CODE_DEPLOY or EXTERNAL), Terraform should not manage the deployment fields.

Doing it manually with terraform import

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