ECS service and target group

• associate ECS service to load balancer
• define target group for load balancer
• running tasks of this ECS service become targets of this target group

#cloudformation template snippet
Service:
    Type: "AWS::ECS::Service"
    Properties:
      Cluster: !FindInMap [BuildEnvironment, !Ref 'EnvironmentType', "cluster"]
      DesiredCount: !FindInMap [BuildEnvironment, !Ref 'EnvironmentType', "desire"]
      LoadBalancers:
        - ContainerName: !Sub "${EnvironmentType}-${APP}"
          ContainerPort: 80
          TargetGroupArn: my_target_group_arn