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Design for New SolutionshardMultiple ChoiceObjective-mapped

SAP-C02 Design for New Solutions Practice Question

A company is designing a microservices architecture on ECS with Fargate. Services need to communicate securely within a VPC and be accessible from the internet via an Application Load Balancer. The solution must minimize operational overhead. Which networking configuration should be used?

⚠ Common exam trap

Many exam-takers confuse the need for a NAT Gateway with outbound-only internet access, mistakenly thinking private subnets cannot reach the internet at all, or they assume an NLB is sufficient for HTTP-based microservices without considering Layer 7 routing requirements.

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

Services in private subnets with a NAT Gateway and an ALB in public subnets.

Placing ECS Fargate services in private subnets ensures they are not directly exposed to the internet, enhancing security. The Application Load Balancer (ALB) in public subnets handles internet-facing traffic and forwards requests to the private services. A NAT Gateway is required for the private services to initiate outbound internet access (e.g., for pulling container images or external dependencies), while the ALB provides inbound connectivity without exposing the services directly. This setup minimizes operational overhead by using AWS-managed components (Fargate, ALB, NAT Gateway) and avoids managing bastion hosts or custom routing.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Services in private subnets with a NAT Gateway and an ALB in public subnets.

    Why this is correct

    Private subnets provide isolation, NAT for outbound, ALB for inbound.

  • Services in private subnets with a VPC endpoint and an NLB.

    Why it's wrong here

    NLB is not ideal for HTTP traffic.

  • Services in a single public subnet with an ALB.

    Why it's wrong here

    Single subnet lacks high availability.

  • Services in public subnets with Internet Gateways and an ALB.

    Why it's wrong here

    Public subnets expose services directly, less secure.

Visual reference

Inside (Private) PC-A 10.0.0.1 PC-B 10.0.0.2 NAT Router Outside (Public) 203.0.113.1 Inside Global Server PAT: many private IPs share one public IP via unique port numbers

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This SAP-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 SAP-C02 exam.