ANS-C01 Network Implementation Practice Question
A company is designing a highly available architecture for a web application using an Application Load Balancer (ALB) in multiple Availability Zones. Which TWO configurations are required to achieve high availability?
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
✓
The ALB must be configured with subnets in at least two Availability Zones
The ALB must be configured with subnets in at least two Availability Zones to remain available if one AZ fails. Option B is correct because an internet-facing ALB is required to accept traffic from the internet; an internal ALB would not be accessible. Option C is incorrect because high availability does not require three instances; two instances (one per AZ) can provide high availability. Option D is incorrect because NAT gateways are not required for ALB high availability; they are used for outbound internet access from private subnets. Option E is incorrect because cross-zone load balancing is enabled by default, but it is not a requirement for high availability; high availability is achieved by having instances in multiple AZs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The ALB must be configured with subnets in at least two Availability Zones
Why this is correct
Multiple AZs provide redundancy.
- ✓
The ALB must be internet-facing
Why this is correct
Internet-facing scheme is needed for internet traffic.
- ✗
At least three EC2 instances must be registered with the ALB
Why it's wrong here
Minimum two instances in different AZs are sufficient.
- ✗
A NAT gateway must be deployed in each Availability Zone
Why it's wrong here
NAT gateway is for outbound traffic, not ALB HA.
- ✗
Cross-zone load balancing must be enabled on the ALB
Why it's wrong here
Cross-zone load balancing is enabled by default but not required for HA.
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Variation 1. A company is designing a highly available architecture for a web application using an Application Load Balancer (ALB) across multiple Availability Zones. Which TWO actions should be taken to ensure high availability?
easy- A.Use a Network Load Balancer instead of an ALB.
- ✓ B.Register EC2 instances in multiple Availability Zones.
- C.Place the EC2 instances in a single Availability Zone.
- D.Configure the ALB as internal.
- ✓ E.Configure the ALB as internet-facing.
Why B: Registering EC2 instances in multiple Availability Zones ensures that if one AZ becomes unavailable, the ALB can route traffic to healthy instances in another AZ. This is a fundamental requirement for high availability because the ALB distributes incoming traffic across targets in different AZs, and if all instances are in a single AZ, that AZ becomes a single point of failure.
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.