AWS Certified SysOps Administrator SOA-C01 – Question097

A sys admin has created a shopping cart application and hosted it on EC2. The EC2 instances are running behind ELB. The admin wants to ensure that the end user request will always go to the EC2 instance where the user session has been created. How can the admin configure this?

A. Enable ELB cross zone load balancing
B. Enable ELB cookie setup
C. Enable ELB sticky session
D. Enable ELB connection draining

Correct Answer: C

Explanation:

Explanation: Generally, AWS ELB routes each request to a zone with the minimum load. The Elastic Load Balancer provides a feature called sticky session which binds the user’s session with a specific EC2 instance. If the sticky session is enabled the first request from the user will be redirected to any of the EC2 instances. But, henceforth, all requests from the same user will be redirected to the same EC2 instance. This ensures that all requests coming from the user during the session will be sent to the same application instance.