AWS Certified SysOps Administrator – Associate (legacy) — Question 204

A company has created an online retail application that is hosted on a fleet of Amazon EC2 instances behind an ELB Application Load Balancer. User authentication is handled at the individual EC2 instance level. Once a user is authenticated; all requests from that user must go to the same EC2 instance.
What should the SysOps Administrator enable to meet these requirements?

Answer options

• A. ELB TCP listeners
• B. ELB sticky sessions
• C. ELB connection draining
• D. ELB cross-zone load balancing

Correct answer: B

Explanation

ELB sticky sessions allow a user's requests to consistently be routed to the same EC2 instance after they have authenticated, which is essential in this scenario. The other options do not provide the required session persistence; TCP listeners manage protocols, connection draining is for gracefully handling instance termination, and cross-zone load balancing distributes traffic across multiple availability zones but does not ensure request consistency for authenticated users.