ANS-C01 Question 85
Select 2Your organization has deployed an application behind an Application Load Balancer (ALB) in AWS. The application requires session persistence to ensure that users are always routed to the same backend instance during their session. Additionally, due to unpredictable traffic patterns, you want to optimize resource utilization across all backend instances in multiple Availability Zones. Which combination of configuration options should you enable on the ALB to meet these requirements?
- A
Enable cross-zone load balancing
- B
Enable sticky sessions (session affinity)
- C
Configure the ALB to use a weighted round-robin routing algorithm
- D
Enable Proxy Protocol
- E
Disable HTTP keep-alive on the target instances
Show answer and explanation
Correct answers: A, B
Explanation
To meet the application's requirements for session persistence and optimized resource utilization across Availability Zones, you need to enable sticky sessions and cross-zone load balancing. Sticky sessions ensure that users are routed to the same backend instance during their session, while cross-zone load balancing distributes traffic evenly across all backend instances in the target group, regardless of the Availability Zone. Other options like Proxy Protocol and disabling HTTP keep-alive are unrelated to the specific requirements of the scenario.
- A. Correct.
Enabling cross-zone load balancing ensures that traffic is distributed evenly across all backend instances in all Availability Zones, optimizing resource utilization.
- B. Correct.
Enabling sticky sessions (session affinity) ensures that users are consistently routed to the same backend instance during their session, which supports session persistence.
- C. Incorrect.
Weighted round-robin is not a configuration option for an ALB; ALBs use a least outstanding requests routing algorithm by default. This option is irrelevant to the scenario.
- D. Incorrect.
Proxy Protocol is used for passing the client's IP address and port information to the backend instances. It is not relevant for session persistence or cross-zone load balancing.
- E. Incorrect.
Disabling HTTP keep-alive on target instances is not recommended for applications requiring session persistence, as it could negatively impact performance and does not align with the requirements.