DVA-C02 Development with AWS Services Practice Question
Which TWO AWS services can be used to decouple microservices in a distributed application? (Choose TWO.)
⚠ Common exam trap
Candidates often confuse Elastic Load Balancer (ELB) with a message broker, but ELB operates at the transport layer (TCP/HTTP) for synchronous load balancing, not for asynchronous decoupling via queues or pub/sub messaging.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Amazon Simple Notification Service (SNS)
Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service that enables microservices to communicate asynchronously by broadcasting messages to multiple subscribers (e.g., SQS queues, Lambda functions, HTTP endpoints). This decouples the producer from the consumers, allowing each microservice to scale and fail independently without blocking the sender.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon CloudWatch
Why it's wrong here
Amazon CloudWatch is primarily an observability and monitoring service that collects and tracks metrics, collects and monitors log files, and sets alarms. While crucial for understanding microservice health and performance, it does not provide any messaging, queuing, or event-driven capabilities to facilitate asynchronous communication or independent operation between services, which are fundamental for decoupling.
- ✗
Elastic Load Balancer (ELB)
Why it's wrong here
An Elastic Load Balancer distributes incoming application traffic across multiple targets, such as EC2 instances, in multiple Availability Zones, enhancing application availability and scalability. However, ELB operates as a synchronous request router, forwarding client requests directly to backend services. It does not introduce an asynchronous buffer or messaging layer to enable services to operate independently without direct knowledge of each other, thus not providing decoupling.
- ✓
Amazon Simple Notification Service (SNS)
Why this is correct
Amazon SNS is a fully managed publish/subscribe messaging service that effectively decouples microservices by allowing publishers to send messages to a central topic. This topic then fans out those messages to multiple subscribed endpoints or services asynchronously, ensuring that the publisher does not need to know about or directly interact with the consumers. This pattern promotes loose coupling, independent scaling, and fault tolerance across the system.
- ✓
Amazon Simple Queue Service (SQS)
Why this is correct
Amazon SQS is a fully managed message queuing service that enables robust decoupling by providing an asynchronous buffer between producer and consumer microservices. Producers can send messages to an SQS queue without waiting for consumers to process them, allowing services to operate independently, handle varying loads, and recover from failures without direct synchronous dependencies. This enhances system resilience and scalability.
- ✗
Amazon Route 53
Why it's wrong here
Amazon Route 53 is a highly available and scalable cloud Domain Name System (DNS) web service that translates human-readable domain names into IP addresses and routes internet traffic to various AWS resources. While essential for service discovery and traffic management, Route 53 operates at the DNS layer and does not offer any messaging, queuing, or event-driven capabilities necessary for achieving asynchronous communication and decoupling between microservices.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DVA-C02 exam.