SOA-C02 Question 79
Select 3Your company hosts a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application must remain highly available and resilient to failure across multiple Availability Zones. You are tasked with designing a solution to meet these requirements. Which of the following steps should you implement?
- A
Deploy the EC2 instances in at least two Availability Zones within the same AWS Region.
- B
Configure the Auto Scaling group to span multiple Availability Zones.
- C
Use an Elastic IP address to associate with the Application Load Balancer.
- D
Enable Cross-Zone Load Balancing on the Application Load Balancer.
- E
Configure the Auto Scaling group to terminate instances in one Availability Zone before scaling in other zones.
Show answer and explanation
Correct answers: A, B, D
Explanation
To achieve high availability and resilience, you must distribute resources across multiple Availability Zones, configure Auto Scaling groups for scalability and fault tolerance, and enable Cross-Zone Load Balancing to ensure even traffic distribution. These configurations collectively address potential failures and maintain application uptime.
- A. Correct.
Correct. Deploying EC2 instances in multiple Availability Zones ensures high availability and resilience to failure in the event of an AZ-level outage.
- B. Correct.
Correct. Configuring the Auto Scaling group to span multiple AZs ensures that the EC2 instances are distributed across zones for fault tolerance and scalability.
- C. Incorrect.
Incorrect. Elastic IP addresses are typically used for static IP mapping to resources like individual EC2 instances, not for load balancers. ALBs manage traffic distribution automatically and don’t use Elastic IPs.
- D. Correct.
Correct. Cross-Zone Load Balancing ensures that traffic is evenly distributed across instances in all enabled Availability Zones, improving overall availability and fault tolerance.
- E. Incorrect.
Incorrect. Terminating instances in one AZ before scaling in other zones could reduce fault tolerance and risks impacting application availability if that AZ experiences a failure.