ANS-C01 Question 78
Select 2You are designing a high-traffic web application that requires a highly available and scalable architecture. Your application is deployed in multiple Availability Zones (AZs) within a single AWS region. When scaling your Application Load Balancer (ALB), what factors should you consider to ensure optimal performance and availability?
- A
The number of unique IP addresses that can be allocated to the ALB in each subnet
- B
The application’s response time to ensure that the ALB can handle scaling events effectively
- C
The number of target groups associated with the ALB
- D
The maximum number of listeners supported by the ALB
- E
The ALB's cross-zone load balancing configuration
Show answer and explanation
Correct answers: A, E
Explanation
When scaling an ALB, the number of unique IP addresses in each subnet is crucial because the ALB requires an Elastic Network Interface (ENI) in each AZ. Each ENI consumes an IP address, and the number of available IPs in the subnet can limit the scalability of the ALB. Additionally, enabling cross-zone load balancing ensures that traffic is evenly distributed across all AZs, even if some AZs have fewer healthy targets, which enhances both scalability and availability.
- A. Correct.
Correct: The number of unique IP addresses in each subnet directly impacts the ALB's ability to scale since each ALB node in an AZ requires an IP address from the subnet.
- B. Incorrect.
Incorrect: While application response time is important for end-user experience, it does not directly factor into the scaling capabilities of the ALB.
- C. Incorrect.
Incorrect: The number of target groups impacts routing granularity but does not affect the scaling capabilities of the ALB.
- D. Incorrect.
Incorrect: The maximum number of listeners affects how many protocols/ports the ALB can listen on, but it is not directly related to scaling.
- E. Correct.
Correct: Cross-zone load balancing configuration impacts how traffic is distributed across AZs and can influence the effective utilization of backend resources, which is critical for scaling.