SOA-C02 Question 92
Select 3You are managing a web application running on a fleet of Amazon EC2 instances behind an Application Load Balancer (ALB). The application stores user-uploaded files that need to be accessible to all instances in the fleet. Additionally, you want to ensure fault tolerance for both the application and the file storage solution. Which combination of configurations will meet these requirements?
- A
Configure an Amazon Elastic File System (Amazon EFS) and mount it to all EC2 instances.
- B
Use an Auto Scaling group for the EC2 instances with a minimum of two instances across multiple Availability Zones.
- C
Store the user-uploaded files locally on each EC2 instance.
- D
Allocate an Elastic IP address to the Application Load Balancer.
- E
Enable cross-zone load balancing on the Application Load Balancer.
Show answer and explanation
Correct answers: A, B, E
Explanation
To implement a fault-tolerant workload for this scenario, you need a highly available file storage solution (Amazon EFS) and fault-tolerant compute infrastructure (Auto Scaling across multiple Availability Zones). Additionally, enabling cross-zone load balancing on the ALB ensures balanced traffic distribution, improving fault tolerance. Storing files locally or using Elastic IP for the ALB does not address the fault tolerance or high availability requirements.
- A. Correct.
Correct. Amazon EFS provides a fault-tolerant file storage solution that can be mounted across multiple EC2 instances, ensuring shared and highly available storage.
- B. Correct.
Correct. Using an Auto Scaling group with instances spread across multiple Availability Zones ensures fault tolerance for the compute layer of the application.
- C. Incorrect.
Incorrect. Storing files locally on each EC2 instance is not fault-tolerant as the files will be lost if the instance terminates.
- D. Incorrect.
Incorrect. Elastic IP addresses are used for static IP management and are not relevant to fault tolerance for this scenario.
- E. Correct.
Correct. Enabling cross-zone load balancing ensures that traffic is evenly distributed across all instances in different Availability Zones, improving fault tolerance and availability.