ANS-C01 Network Design Practice Question
A company is designing a network architecture for a critical application that requires high availability and fault tolerance. The application will be deployed on EC2 instances in an Auto Scaling group across three Availability Zones. The instances must be able to communicate with each other across AZs. Which TWO design decisions improve the fault tolerance of the application? (Choose TWO.)
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that a single NAT Gateway or a single NLB is sufficient for high availability, but the trap here is that these components must be deployed in a redundant manner (e.g., one per AZ) to avoid a single point of failure, while VPC endpoints improve security but not fault tolerance.
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
✓
Configure the Auto Scaling group to launch instances in multiple Availability Zones
Launching instances in multiple Availability Zones (AZs) ensures that if one AZ fails, the Auto Scaling group can still maintain capacity from the remaining AZs, providing fault tolerance. This design leverages the isolation boundaries of AZs within a region, which are physically separate data centers with independent power and networking.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use a single NAT Gateway in one Availability Zone for internet access
Why it's wrong here
A single NAT Gateway creates a single point of failure; deploy one per AZ.
- ✗
Use VPC endpoints for Amazon S3 to reduce internet dependency
Why it's wrong here
VPC endpoints do not improve inter-instance communication fault tolerance.
- ✓
Configure the Auto Scaling group to launch instances in multiple Availability Zones
Why this is correct
Auto Scaling across AZs automatically replaces failed instances and maintains capacity.
- ✗
Use a single Network Load Balancer in one Availability Zone
Why it's wrong here
A single NLB in one AZ is a single point of failure; use cross-zone load balancing.
- ✓
Deploy EC2 instances evenly across three Availability Zones
Why this is correct
Distributing instances across AZs ensures availability if one AZ fails.
Go deeper
Related to this question
About these practice questions
Courseiva writes every ANS-C01 question from scratch — 1,621 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-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 ANS-C01 exam.