Overview

What is ECS Express Mode?

ECS Express Mode Express Gateway Service
The aws_ecs_express_gateway_service Terraform resource that provisions an ECS service with managed ALB, auto scaling, and simplified configuration for HTTP/HTTPS web applications and APIs. is a simplified deployment model for Amazon ECS. It lets you deploy stateless HTTP/HTTPS containers without provisioning separate ALB, target group, listener, or auto scaling resources.

Your entire service infrastructure becomes one Terraform resource:

main.tf

resource "aws_ecs_express_gateway_service" "this" {
  service_name            = "my-service"
  cluster                 = aws_ecs_cluster.this.arn
  task_definition         = aws_ecs_task_definition.this.arn
  infrastructure_role_arn = aws_iam_role.infrastructure.arn

  primary_container {
    container_name    = "app"
    container_port    = 8000
    health_check_path = "/health"
  }

  network_configuration {
    subnets         = aws_subnet.public[*].id
    security_groups = [aws_security_group.web.id]
    access_type     = "PUBLIC"
  }

  scaling_target {
    auto_scaling_metric       = "CPU"
    auto_scaling_target_value = 70
    min_task_count            = 1
    max_task_count            = 4
  }
}

That’s it. No ALB resource, no target group, no listener rules, no scaling policies.

The demo application

This walkthrough documents a working project: a Bedrock Bedrock
AWS fully managed service providing foundation models for generative AI applications. -powered image analysis API that:

1. Runs a FastAPI container with a /health endpoint and Swagger UI at /docs
2. Accepts image uploads and returns AI-generated descriptions via Claude Foundation Model
   A pre-trained large language or multimodal model available through Amazon Bedrock.
3. Deploys to a public HTTPS endpoint with auto scaling and health-check-driven rollback
4. Uses a single terraform apply to provision the entire stack

What Terraform manages

Resource	Purpose	File
aws_ecs_express_gateway_service	Service with managed ALB, scaling, health checks	main.tf
aws_ecs_cluster	Fargate-backed cluster	main.tf
aws_ecs_task_definition	Container image, port, environment	main.tf
aws_vpc + subnets	Network with public subnets and IGW	main.tf
aws_security_group	VPC CIDR ingress on container port	main.tf
aws_iam_role (×3)	Task execution, infrastructure, task roles	main.tf

What this walkthrough covers

Section	Content
ECS Express Mode	Concepts, Express Gateway Service resource, auto scaling, health checks
IAM Roles	Three-role model, trust policies, Bedrock permissions
Networking	VPC layout, security groups, public subnets, ingress configuration
Deployment	Terraform apply, verifying health, accessing the web UI
Troubleshooting	Rollback loops, health check failures, common root causes

Note

This walkthrough documents terraform-aws-ecs-express-mode-demo. Clone that repo to follow along with deployment steps.