Q60 — AWS SAA-C03 Ch.17

Question 60 of 89 | ← Chapter 17

Q1360. company deployed a three-tier web application in a single Availability Zone in the us-east-1 Region on a single Amazon EC2 instance. Usage of the application is growing. A solutions architect needs to ensure that the application can handle the growing amount of traffic. The solutions architect also needs to ensure the application is resilient. Which solution will meet these requirements MOST cost-effectively?

• A. Create two additional EC2 instance spread across two separate Availability Zones. Create an Application Load Balancer(ALB). Configure the ALB to route traffic to a target group that contains all three instances. Create an Amazon CloudWatch alarm to scale the EC2 instances vertically to handle the application traffic.
• B. Create eight additional EC2 instances spread across in three separate Availability Zones. Create an Application Load Balancer(ALB). Configure the ALB to route traffic to a target group that contains all nine instances. Create an Amazon CloudWatch alarm to scale the EC2 instances horizontally to handle the application traffic.
• C. Create an EC2 Auto Scaling group that contains a minimum of three EC2 instances in the same Availability Zone, Create an Application Load Balancer(ALB), Configure the ALB to route traffic to a target group that contains all the instances. Configure scheduled scaling for the Auto Scaling group.
• D. Create an EC2 Auto Scaling group that contains a minimum of three EC2 instances spread across Availability Zones. Create an Application Load Balancer(ALB). Configure the ALB to route traffic to a target ALB to route traffic to a target group that contains all the instances. Create an Amazon CloudWatch alarm to scale the EC2 instances vertically to handle the application traffic. ✓

Correct Answer: D. Create an EC2 Auto Scaling group that contains a minimum of three EC2 instances spread across Availability Zones. Create an Application Load Balancer(ALB). Configure the ALB to route traffic to a target ALB to route traffic to a target group that contains all the instances. Create an Amazon CloudWatch alarm to scale the EC2 instances vertically to handle the application traffic.

Explanation

A OR D.D.The correct answer is D (with a correction in the description). However, since the original option D has a minor typo ("target ALB to route traffic to a target group"), the intended correct answer is likely a modified version of D that properly describes horizontal scaling (not vertical scaling).Corrected Option D (Conceptual Fix):"Create an EC2 Auto Scaling group that contains a minimum of three EC2 instances spread across Availability Zones. Create an Application Load Balancer (ALB). Configure the ALB to route traffic to a target group that contains all the instances. Create an Amazon CloudWatch alarm to scale the EC2 instances horizontally to handle the application traffic."Explanation:The company needs a cost-effective, resilient solution for a growing three-tier web application currently running on a single EC2 instance in one AZ. The solution must:Handle increasing traffic (scalability).Be resilient (fault-tolerant across AZs).Be cost-effective (avoid over-provisioning).Why the Corrected Option D is the Best Choice:Auto Scaling Group (ASG) with multi-AZ deploymentDistributes instances across AZs Ensures high availability (if one AZ fails, others continue serving traffic). Minimum of three instances Provides redundancy while keeping costs low.Application Load Balancer (ALB)Distributes traffic evenly across instances in the target group. Supports health checks Automatically replaces unhealthy instances.Horizontal scaling (via CloudWatch alarms)Adds/removes instances based on demand (e.g., CPU utilization). More cost-effective than vertical scaling (scaling up instance sizes is often pricier).Why Other Options Are Incorrect:A. Two additional instances + ALB + vertical scalingVertical scaling is expensive Larger instances cost more than multiple smaller ones. Only three instances total Less resilient than multi-AZ deployment.B. Eight additional instances + ALB + horizontal scalingOver-provisioned Nine instances may be unnecessary for initial scaling needs (higher cost). No minimum instance constraint Could scale down to zero if not configured properly (risk of downtime).C. ASG in a single AZ + scheduled scalingSingle AZ = no fault tolerance If the AZ fails, the application goes down. Scheduled scaling is inflexible Cannot adapt to unpredictable traffic spikes.Comparison Table:OptionResilience (Multi-AZ)Scalability (Horizontal/Vertical)Cost-EffectivenessBest For Corrected D(3+ AZs)(Horizontal)(Optimal instance count)Growing traffic with fault tolerance A (Single AZ) (Vertical) (Expensive scaling)Small-scale, predictable workloads B(3 AZs)(Horizontal) (Over-provisioned)Large-scale, unpredictable workloads C (Single AZ) (Scheduled) (No fault tolerance)Non-critical, predictable workloads Conclusion:The most cost-effective and resilient solution is Corrected Option D:Multi-AZ Auto Scaling Group Ensures high availability.ALB for traffic distribution Improves performance and reliability.Horizontal scaling Adapts to traffic changes efficiently.Avoid Options A, B, and C (they either lack fault tolerance, are over-provisioned, or use inefficient scaling).Final Answer: D (with the correction to horizontal scaling).