Q27 — AWS DOP-C02 Ch.3

Question 27 of 100 | ← Chapter 3

A company is testing a web application running on Amazon EC2 instances behind an Application Load Balancer. These instances run in an Auto Scaling group spanning multiple Availability Zones. During deployment of new software, the company uses a blue/green deployment process. During the testing period, users are automatically logged out of the application. Testers report that all users are logged out when deploying the new version of the application. The development team needs a solution to ensure users remain logged in during scaling events and application deployments.

• A. Enable intelligent session stickiness on the load balancer and modify the application to check for existing sessions.
• B. Enable session sharing on the load balancer and modify the application to read from the session store.
• C. Store user session information in an Amazon S3 bucket and modify the application to read session information from the bucket.
• D. Modify the application to store user session information in an Amazon ElastiCache cluster. ✓

Correct Answer: D. Modify the application to store user session information in an Amazon ElastiCache cluster.

Explanation

Answer D is the most effective method. An ElastiCache cluster provides fast data access and low-latency responses, making it ideal for storing and rapidly retrieving user session information. During application deployments and scaling events, the application can quickly retrieve user session information from ElastiCache, ensuring users remain logged in. Option A's intelligent session stickiness may be insufficiently stable and efficient in this complex scenario. Option B's session sharing may introduce compatibility and data consistency issues. Option C's use of Amazon S3 for session storage results in relatively slow read speeds, potentially degrading user experience. Therefore, option D is the most effective method to ensure users remain logged in.