SOA-C02 Question 78
Select 2You are managing an application hosted on Amazon EC2 instances behind an Application Load Balancer (ALB) in a single Availability Zone. After a recent outage in that Availability Zone, your manager has asked you to implement a solution that ensures high availability for the application. Which of the following steps should you take to meet this requirement?
- A
Deploy additional EC2 instances in a second Availability Zone and register them with the existing ALB.
- B
Enable cross-zone load balancing on the ALB.
- C
Configure an Amazon Route 53 health check to monitor the ALB.
- D
Set up an Auto Scaling group with multiple Availability Zones enabled.
- E
Move all EC2 instances to a larger instance type for better performance.
Show answer and explanation
Correct answers: A, D
Explanation
To implement high availability, you must ensure your application can withstand the failure of a single Availability Zone. Deploying EC2 instances across multiple Availability Zones and using an Auto Scaling group configured for multiple zones ensures that your application remains resilient and available during outages.
- A. Correct.
Deploying EC2 instances in a second Availability Zone ensures the application remains available even if one Availability Zone becomes unavailable. This is a key step in achieving high availability.
- B. Incorrect.
Enabling cross-zone load balancing helps distribute traffic evenly across targets in multiple zones but does not directly address resilience if instances are only in one Availability Zone.
- C. Incorrect.
Configuring an Amazon Route 53 health check is useful for monitoring and failover in DNS routing but does not address the lack of high availability across multiple Availability Zones.
- D. Correct.
An Auto Scaling group configured across multiple Availability Zones ensures instances are automatically launched and balanced across zones, providing both scalability and high availability.
- E. Incorrect.
Moving to a larger instance type may improve performance but does not address the single point of failure caused by hosting all instances in a single Availability Zone.