I think the answer here is "D" because usually when you see terms like "monolithic" the answer will likely refer to microservices.

D is organic pattern, lift and shift, decompose to containers, first making most use of existing code, whilst new features can be added over time with lambda+api gw later. A is leapfrog pattern. requiring refactoring all code up front.

Amazon API Gateway and Amplify both server less. Also you can import your code from GitHub in the amplify.

The company wants to keep much of its existing code. So the preferable solution is ECS. However the option D does not mention AWS Fargate which would cover the 'least operational overhead ' part.

Different teams working means " microservices based architecture" so basically decoupling the application ..u can achieve this only by containerizing the app so answer is D

B allows for a serverless architecture using AWS Lambda functions, which are highly scalable and require minimal operational overhead. AWS Amplify can help in managing the front-end code, while Amazon API Gateway integrated with AWS Lambda can handle the backend services. D imo is not the best option in this scenario. While ECS can be a good choice for containerized workloads, it might introduce more operational overhead compared to a serverless solution like AWS Lambda and AWS Amplify.

I have a problem with this question. "The company wants to keep as much of the front-end code and the backend code as possible" So containerization is the solution here (D)? ABC don't make much sense so I will go with D but using containers for FE/BE code and configuring ALB for ECS (hopefully for frontend containers) is a pain in practice. Maybe this is worded in a bad way.

Original state: monolithic with FE and BE code Wanted state: seperate to mutilple components for diff. teams as Microservices B is correct to decouple monolithic to microservices. D still keep monolithic application in ECS.

IT is B. AWS amplify. AWS Amplify will help seperate FE and BE. I agree with MM_Korvinus answer.

https://aws.amazon.com/tutorials/break-monolith-app-microservices-ecs-docker-ec2/module-three/ This page explained clearly why D is the correct answer

'Non-monolithic', 'smaller applications', 'minimized operational overhead' all screaming 'microservices'.

The reasons are: ECS allows running Docker containers, so the existing monolithic app can be containerized and run on ECS with minimal code changes. The app can be broken into smaller microservices by containerizing different components and managing them separately. ECS provides auto scaling capabilities to scale each microservice independently. Using an Application Load Balancer with ECS enables distributing traffic across containers and auto scaling. ECS has minimal operational overhead compared to managing EC2 instances directly. Serverless options like Lambda and API Gateway would require significant code refactoring which is not ideal for migrating an existing app.

Honestly, from my experience, the minimal operational overhead is with Amplify and API Gateway with lambdas. Both services have neat release features, you do not need to fiddle around ECS configurations as everything is server-less, which is also highly scalable. Eventhough it is much harder to refactor monolithic app to this set-up it is definitely easier to operate. Not talking about complexities around ALB.

ECS provides a highly scalable and managed environment for running containerized applications, reducing operational overhead. By setting up an ALB with ECS as the target, traffic can be distributed across multiple instances of the application for scalability and availability. This solution enables different teams to manage each application independently, promoting team autonomy and efficient development. A is more suitable for event-driven and serverless workloads. It may not be the ideal choice for migrating a monolithic application and maintaining the existing codebase. B integrates with Lambda and API Gateway, it may not provide the required flexibility for breaking the application into smaller applications and managing them independently. C would involve managing the infrastructure and scaling manually. It may result in higher operational overhead compared to using a container service like ECS.

I was confused about this, but actually Amazon ECS service can be configured to use Elastic Load Balancing to distribute traffic evenly across the tasks in your service. https://docs.aws.amazon.com/AmazonECS/latest/userguide/create-application-load-balancer.html

monolithic = microservices = ECS

I thought ALB is about distributing load. How do we want to use it to connect decoupled applications that needs to call themselves. I am kind of confused why most people are going with D. I think I will go with A.