A Company Is Building a Voting System for a Popular

question 315

Multiple Choice

A company is building a voting system for a popular TV show, viewers win watch the performances then visit the show's website to vote for their favorite performer.  It is expected that in a short period of time after the show has finished the site will receive millions of visitors. The visitors will first login to the site using their Amazon.com credentials and then submit their vote.  After the voting is completed the page will display the vote totals.  The company needs to build the site such that can handle the rapid influx of traffic while maintaining good performance but also wants to keep costs to a minimum. Which of the design patterns below should they use?

• A) Use CloudFront and an Elastic Load balancer in front of an auto-scaled set of web servers, the web servers will first call the Login With Amazon service to authenticate the user then process the users vote and store the result into a multi-AZ Relational Database Service instance.
• B) Use CloudFront and the static website hosting feature of S3 with the Javascript SDK to call the Login With Amazon service to authenticate the user, use IAM Roles to gain permissions to a DynamoDB table to store the users vote.
• C) Use CloudFront and an Elastic Load Balancer in front of an auto-scaled set of web servers, the web servers will first call the Login with Amazon service to authenticate the user, the web servers will process the users vote and store the result into a DynamoDB table using IAM Roles for EC2 instances to gain permissions to the DynamoDB table.
• D) Use CloudFront and an Elastic Load Balancer in front of an auto-scaled set of web servers, the web servers will first call the Login With Amazon service to authenticate the user, the web servers win process the users vote and store the result into an SQS queue using IAM Roles for EC2 Instances to gain permissions to the SQS queue. A set of application servers will then retrieve the items from the queue and store the result into a DynamoDB table.

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Definitions:

Perfectly Elastic

A situation in economics where the demand or supply for a good is completely responsive to changes in price, resulting in an infinite elasticity.

Mutual Interdependence

A situation in which a change in price strategy (or in some other strategy) by one firm will affect the sales and profits of another firm (or other firms). Any firm that makes such a change can expect its rivals to react to the change.

Trademarks

Symbols, names, or phrases legally registered or established by use as representing a company or product.

Product Differentiation

A strategy in which one firm’s product is distinguished from competing products by means of its design, related services, quality, location, or other attributes (except price).