What should a solutions architect recommend to meet these requirements?
Use an Amazon Route 53 routing policy to distribute requests to two AWS Regions, each with one Amazon EC2 instance.
Use Amazon EC2 instances in an Auto Scaling group with an Application Load Balancer across multiple Availability Zones.
Use Amazon EC2 instances in a cluster placement group with an Application Load Balancer across multiple Availability Zones.
Use Amazon EC2 instances in a cluster placement group and include the cluster placement group within a new Auto Scaling group.
Explanations:
Using Route 53 to distribute requests across two regions can provide redundancy, but it doesn’t ensure high availability and fault tolerance as effectively as an Auto Scaling group with an Application Load Balancer (ALB) within a single region. This setup may also introduce latency due to cross-region traffic.
This option provides a highly available and fault-tolerant architecture. An Auto Scaling group allows the application to automatically scale based on traffic demands, and an ALB distributes traffic across multiple EC2 instances in different Availability Zones, minimizing latency and enhancing fault tolerance.
A cluster placement group is designed for high throughput and low latency between instances but does not provide high availability across multiple Availability Zones. If an Availability Zone goes down, all instances in that placement group would be impacted.
While using an Auto Scaling group improves scalability, placing the instances in a cluster placement group limits high availability. If one Availability Zone fails, the entire application could become unavailable, which does not meet the fault tolerance requirement.
I assess that the answer is:
Use Amazon EC2 instances in an Auto Scaling group with an Application Load Balancer across multiple Availability Zones.