AWS Certified Solutions Architect – Professional SAP-C01 – Question092

You are designing a multi-platform web application for AWS The application will run on EC2 instances and will be accessed from PCs. Tablets and smart phones Supported accessing platforms are Windows, MacOS, IOS and Android Separate sticky session and SSL certificate setups are required for different platform types.
Which of the following describes the most cost effective and performance efficient architecture setup?

A.
Setup a hybrid architecture to handle session state and SSL certificates on-prem and separate EC2 Instance groups running web applications for different platform types running in a VPC.
B. Set up one ELB for all platforms to distribute load among multiple instance under it Each EC2 instance implements ail functionality for a particular platform.
C. Set up two ELBs The first ELB handles SSL certificates for all platforms and the second ELB handles session stickiness for all platforms for each ELB run separate EC2 instance groups to handle the web application for each platform.
D. Assign multiple ELBS to an EC2 instance or group of EC2 instances running the common components of the web application, one ELB for each platform type Session stickiness and SSL termination are done at the ELBs.

Correct Answer: D

Explanation:

Explanation: One ELB cannot handle different SSL certificates but since we are using sticky sessions it must be handled at the ELB level. SSL could be handled on the EC2 instances only with TCP configured ELB, ELB supports sticky sessions only in HTTP/ HTTPS configurations.
The way the Elastic Load Balancer does session stickiness is on a HTTP/HTTPS listener is by utilizing an HTTP cookie. If SSL traffic is not terminated on the Elastic Load Balancer and is terminated on the back-end instance, the Elastic Load Balancer has no visibility into the HTTP headers and therefore can not set or read any of the HTTP headers being passed back and forth. Reference:
http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGui…