PAS-C01 Technology Practice Question
A company is designing a microservices architecture on Amazon ECS with Fargate. The services need to communicate securely and be accessible only within the VPC. Which TWO steps should the solutions architect take to meet these requirements? (Choose TWO.)
⚠ Common exam trap
A common mix-up: candidates confuse public subnets with the ability to communicate privately, or assume that an internet gateway is required for any inter-service communication, when in fact internal load balancers and VPC endpoints provide fully private connectivity.
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
✓
Use an internal Application Load Balancer to distribute traffic between services.
An internal Application Load Balancer (ALB) operates within a VPC and does not expose a public endpoint, ensuring that traffic between microservices remains private. It distributes incoming requests to Fargate tasks based on defined rules, enabling secure, internal communication without internet access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Attach an Internet Gateway to the VPC and configure route tables for the private subnets.
Why it's wrong here
An Internet Gateway provides internet access, not needed for internal communication.
- ✗
Place the Fargate tasks in public subnets to allow them to communicate with each other through the internet gateway.
Why it's wrong here
Public subnets and internet gateway expose services to the internet.
- ✗
Use AWS Cloud Map for service discovery and register a public DNS name for each service.
Why it's wrong here
Public DNS would make services accessible from the internet.
- ✓
Use an internal Application Load Balancer to distribute traffic between services.
Why this is correct
Internal ALB routes traffic within the VPC.
- ✓
Create a VPC endpoint for Amazon ECS to allow the service to call the ECS API without internet access.
Why this is correct
VPC endpoints keep API traffic within the VPC.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PAS-C01 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 PAS-C01 exam.