AWS Certified Solutions Architect High Availability and Scalability 3

Question 1

A company wants to run a stateless web tier that scales to zero when there is no traffic. Which AWS service best achieves this with the lowest operational overhead?

Accepted Answer

AWS Lambda with API Gateway

Answer

Lambda scales to zero automatically and only runs when invoked, making it ideal for workloads that need true scale-to-zero with no idle costs.

Question 2

An application requires that user sessions persist even when requests are routed to different EC2 instances. Which solution maintains high availability without sticky sessions?

Accepted Answer

Store session data in Amazon ElastiCache Redis

Answer

Storing sessions in ElastiCache Redis externalizes state so any instance can serve any request, enabling true stateless scaling.

Question 3

A company deploys a Multi-AZ RDS instance and a read replica in a different region. A full region outage occurs. What manual action is required?

Accepted Answer

The read replica must be manually promoted to a standalone DB instance

Answer

Cross-region read replicas require manual promotion during a region outage; they are not part of the automatic Multi-AZ failover mechanism.

Question 4

Which Auto Scaling lifecycle hook allows a custom script to run before an instance is terminated during a scale-in event?

Accepted Answer

EC2_INSTANCE_TERMINATING hook with CONTINUE action

Answer

The EC2_INSTANCE_TERMINATING hook pauses termination, allowing cleanup scripts to run, and CONTINUE resumes the termination afterward.

Question 5

A solutions architect needs an active-active multi-region architecture for a DynamoDB-backed application. Which DynamoDB feature enables this?

Accepted Answer

DynamoDB Global Tables

Answer

DynamoDB Global Tables provide multi-region, fully replicated tables that support active-active reads and writes in any configured region.

AWS Practice Test

AWS Practice Test

AWS Certified Solutions Architect High Availability and Scalability 3