SAA-C03 Question 286
Select 3A company is designing a highly available web application hosted on Amazon EC2 instances in the us-east-1 Region. The application must be resilient to the failure of an entire Availability Zone. How can the company achieve this?
- A
Deploy the EC2 instances across multiple Availability Zones within the us-east-1 Region.
- B
Deploy the EC2 instances in a single Availability Zone and use an Elastic Load Balancer to distribute traffic.
- C
Use an Auto Scaling group to launch EC2 instances in multiple Availability Zones.
- D
Configure an Amazon RDS Multi-AZ deployment for the application's database.
- E
Deploy the EC2 instances across multiple AWS Regions to ensure high availability.
Show answer and explanation
Correct answers: A, C, D
Explanation
To design a highly available application, the EC2 instances should be distributed across multiple Availability Zones within the same Region. This ensures resilience to the failure of an entire Zone. Using an Auto Scaling group can further enhance fault tolerance by managing instance distribution automatically. Additionally, a Multi-AZ RDS deployment ensures that the application's database remains available even if one Zone becomes unavailable. Deploying across Regions is not required for high availability but is more relevant for disaster recovery scenarios.
- A. Correct.
Correct: Deploying across multiple Availability Zones ensures that the application can continue running even if one Availability Zone fails.
- B. Incorrect.
Incorrect: Deploying in a single Availability Zone creates a single point of failure, even if traffic is balanced using an Elastic Load Balancer.
- C. Correct.
Correct: An Auto Scaling group can distribute EC2 instances across multiple Availability Zones, increasing resilience to Zone failures.
- D. Correct.
Correct: Amazon RDS Multi-AZ deployments provide high availability for databases, which is critical for the overall application resilience.
- E. Incorrect.
Incorrect: While deploying across multiple Regions increases disaster recovery capabilities, it is not necessary for high availability within a single Region.