AWS Certified Solutions Architect High Availability and Scalability 2

Question 1

An application uses an Application Load Balancer with EC2 instances in two Availability Zones. After a recent deployment, one AZ becomes unhealthy. What does the ALB do automatically?

Accepted Answer

Routes all traffic to the healthy AZ while the unhealthy AZ recovers

Answer

ALB automatically detects unhealthy targets via health checks and routes traffic only to healthy targets across remaining AZs.

Question 2

A company wants to scale EC2 instances based on the number of messages in an SQS queue. Which Auto Scaling policy type is most appropriate?

Accepted Answer

Target tracking scaling policy using a custom CloudWatch metric

Answer

Target tracking scaling with a custom CloudWatch metric (e.g., ApproximateNumberOfMessages per instance) is ideal for SQS-driven scaling.

Question 3

Which RDS feature automatically promotes a standby replica to primary when the primary instance fails, minimizing downtime?

Accepted Answer

Multi-AZ failover

Answer

RDS Multi-AZ maintains a synchronous standby that is automatically promoted during a primary failure, typically within 60-120 seconds.

Question 4

A web application needs to handle sudden traffic spikes that last only a few minutes. Which EC2 Auto Scaling feature best handles this without over-provisioning?

Accepted Answer

Warm pools

Answer

Warm pools keep pre-initialized EC2 instances ready to launch quickly, reducing launch latency during sudden short spikes.

Question 5

An Elastic Load Balancer must distribute traffic to EC2 instances across three AZs, but one AZ has significantly fewer instances. Which feature ensures even distribution?

Accepted Answer

Cross-zone load balancing

Answer

Cross-zone load balancing distributes requests evenly across all registered instances in all enabled AZs, regardless of instance count per AZ.

AWS Practice Test

AWS Practice Test

AWS Certified Solutions Architect High Availability and Scalability 2