Let's say you have the following files on your Terraform server.

├── required_providers.tf
├── elastic_container_services (directory)
│   ├── services (directory)
│   ├── ├── fargate (directory)
│   ├── ├── ├── provider.tf
│   ├── ├── ├── task_definition.tf

required_providers.tf will almost always have this.

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
    }
  }
}

Let's say provider.tf has the following. In this example, the "default" profile in /home/username/.aws/config and /home/username/.aws/credentials is being used. This assumes you have setup Terraform as described in Amazon Web Services (AWS) - Getting Started with Terraform.

provider "aws" {
  alias   = "default"
  profile = "default"
  region  = "default"
}

This assumes you have already:

• Created an Elastic Container Service (ECS) Cluster using Terraform
• Created an Elastic Container Service (ECS) Fargate Task Definition using Terraform

An ECS deployment can be:

• EC2 - apps run in EC2 instance
• FARGATE - serverless (no EC2 instances)

services.tf could have something like this.

resource "aws_ecs_service" "ecs-flask-fargate-service" {
  name = "flask-fargate-service"
  launch_type = "FARGATE"
  cluster = aws_ecs_cluster.my-ecs-cluster.id
  task_definition = aws_ecs_task_definition.flask-fargate-task-definition.id
  desired_count = 1

   load_balancer {
     target_group_arn = aws_lb_target_group.ecs-application-load-balancer-target-group.arn
     container_name = aws_ecs_task_definition.flask-fargate-task-definition.id
     container_port = 80
  }

  network_configuration {
    subnets = [data.aws_subnets.subnets.ids[0],data.aws_subnets.subnets.ids[1]]
    security_groups = [data.aws_security_group.ecs-security-group.id]
    assign_public_ip = true
  }

  lifecycle {
    ignore_changes = [task_definition, desired_count]
  }

}

You may need to reissue the terraform init command.

~]# terraform init
Initializing the backend...
Initializing modules...
Initializing provider plugins...
Terraform has been successfully initialized!

The terraform plan command can be used to see what Terraform will try to do.

~]$ terraform plan
Terraform will perform the following actions:

  # aws_ecs_service.ecs-flask-fargate-service will be created
  + resource "aws_ecs_service" "ecs-flask-fargate-service" {
      + cluster                            = "arn:aws:ecs:us-east-2:123456789012:cluster/my-ecs-cluster"
      + deployment_maximum_percent         = 200
      + deployment_minimum_healthy_percent = 100
      + desired_count                      = 1
      + enable_ecs_managed_tags            = false
      + enable_execute_command             = false
      + iam_role                           = (known after apply)
      + id                                 = (known after apply)
      + launch_type                        = "FARGATE"
      + name                               = "flask-fargate-service"
      + platform_version                   = (known after apply)
      + scheduling_strategy                = "REPLICA"
      + tags_all                           = (known after apply)
      + task_definition                    = "flask"
      + triggers                           = (known after apply)
      + wait_for_steady_state              = false

      + load_balancer {
          + container_name   = "flask"
          + container_port   = 80
          + target_group_arn = "arn:aws:elasticloadbalancing:us-east-2:123456789012:targetgroup/ecs-target-group/94d249d96f071434"
        }

      + network_configuration {
          + assign_public_ip = false
          + security_groups  = [
              + "sg-0e01a484310ec2f8e",
            ]
          + subnets          = [
              + "subnet-000368eea6348dcd8",
              + "subnet-00a2efcf89006a953",
            ]
        }
    }

Plan: 1 to add, 0 to change, 0 to destroy.

The terraform apply command can be used to create, update or delete the resource.

terraform apply -auto-approve

The aws ecs list-clusters command can be used to list your Elastic Container Service (ECS) Clusters.

~]$ aws ecs list-clusters
{
    "clusterArns": [
        "arn:aws:ecs:us-east-1:123456789012:cluster/my-ecs-cluster"
    ]
}

The aws ecs list-services command can be used to list the ECS Services that have been created. Something like this should be returned.

]$ aws ecs list-services --cluster arn:aws:ecs:us-east-1:123456789012:cluster/my-ecs-cluster
{
    "serviceArns": [
        "arn:aws:ecs:us-east-1:123456789012:service/my-ecs-cluster/flask-fargate-service"
    ]
}

And the Service should be listed in the AWS ECS console.