Terraform Apply

Setting Terraform Variables

Before deploying, configure the Terraform variables in terraform.tfvars. The terraform-aws-ecs-express-mode-demo project exposes four input variables — all have defaults, so you only need to override values you want to change.

Create a terraform.tfvars file in the repository root:

terraform.tfvars

project     = "ecs-express-mode-demo"
environment = "dev"
aws_region  = "ap-southeast-2"
vpc_cidr    = "10.42.0.0/16"

Variable	Type	Description
project	string	Project name used for resource naming and tagging. Lowercase alphanumeric characters and hyphens only; 3–50 characters.
environment	string	Deployment environment. Must be one of dev, staging, or prod.
aws_region	string	AWS region for resource deployment. Must support your chosen Bedrock foundation model.
vpc_cidr	string	CIDR block for the VPC created by this project (for example, 10.42.0.0/16).

Tip

Choose an aws_region where your Bedrock foundation model is available. The project name is applied to resource names and tags across the stack.

Initializing Terraform

Run terraform init to download provider plugins and initialize the working directory. This step fetches the AWS provider and prepares the local state:

terraform init

You should see output confirming that providers were installed and Terraform is ready:

Initializing the backend...
Initializing provider plugins...
- Finding latest version of hashicorp/aws...
- Installing hashicorp/aws...

Terraform has been successfully initialized!

Running Terraform Apply

With variables configured and providers initialized, run terraform apply to create all resources:

terraform apply

Terraform displays a plan showing the resources it will create. Review the plan and type yes to confirm. The Express Gateway Service 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. resource triggers Express Mode to provision its managed infrastructure alongside your declared resources.

Note

The apply typically takes 3–5 minutes. Most of the time is spent provisioning the ALB and waiting for target group health checks to pass.

What Express Mode Provisions

When Terraform applies the Express Gateway Service 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. resource, ECS Express Mode automatically provisions several managed resources that you would otherwise configure manually with classic ECS:

Resource	What Express Mode Does
Application Load Balancer Shared ALB The Application Load Balancer shared by up to 25 Express services in the same VPC using Host header routing rules.	Creates or reuses a shared ALB in the VPC with Host header routing rules. Up to 25 Express services share a single ALB.
Target group	Registers ECS tasks automatically and configures health checks using the health_check_path you specify.
Auto scaling	Configures target tracking scaling based on the auto_scaling_metric (CPU or memory), scaling between min_task_count and max_task_count.
DNS / Application URL Application URL The unique Express-provisioned HTTPS URL on *.ecs.<region>.on.aws used for all normal application traffic.	Assigns a unique HTTPS endpoint on *.ecs.<region>.on.aws with a managed TLS certificate — no Route 53 or ACM configuration required.
Rollback alarm RollbackAlarm A CloudWatch metric alarm created by Express Mode that triggers automatic deployment rollback when new tasks fail ALB health checks.	Creates a CloudWatch alarm that triggers automatic deployment rollback when new tasks fail ALB health checks.

Caution

You do not declare ALB, target group, listener, or auto scaling resources in your Terraform code when using Express Mode. ECS manages these internally. Attempting to create them separately will conflict with the managed resources.

After Apply Completes

Once terraform apply finishes successfully, Terraform outputs the Application URL Application URL
The unique Express-provisioned HTTPS URL on *.ecs.<region>.on.aws used for all normal application traffic. and other resource identifiers. The next step is verifying the service is healthy and accessible — covered on the Verifying page.

terraform output