AWS Certified Solutions Architect – Professional — Question 944

A large company has many business units. Each business unit has multiple AWS accounts for different purposes. The CIO of the company sees that each business unit has data that would be useful to share with other parts of the company. In total, there are about 10 PB of data that needs to be shared with users in
1,000 AWS accounts. The data is proprietary, so some of it should only be available to users with specific job types. Some of the data is used for throughput of intensive workloads, such as simulations. The number of accounts changes frequently because of new initiatives, acquisitions, and divestitures.
A Solutions Architect has been asked to design a system that will allow for sharing data for use in AWS with all of the employees in the company.
Which approach will allow for secure data sharing in scalable way?

Answer options

• A. Store the data in a single Amazon S3 bucket. Create an IAM role for every combination of job type and business unit that allows for appropriate read/write access based on object prefixes in the S3 bucket. The roles should have trust policies that allow the business unit's AWS accounts to assume their roles. Use IAM in each business unit's AWS account to prevent them from assuming roles for a different job type. Users get credentials to access the data by using AssumeRole from their business unit's AWS account. Users can then use those credentials with an S3 client.
• B. Store the data in a single Amazon S3 bucket. Write a bucket policy that uses conditions to grant read and write access where appropriate, based on each user's business unit and job type. Determine the business unit with the AWS account accessing the bucket and the job type with a prefix in the IAM user's name. Users can access data by using IAM credentials from their business unit's AWS account with an S3 client.
• C. Store the data in a series of Amazon S3 buckets. Create an application running in Amazon EC2 that is integrated with the company's identity provider (IdP) that authenticates users and allows them to download or upload data through the application. The application uses the business unit and job type information in the IdP to control what users can upload and download through the application. The users can access the data through the application's API.
• D. Store the data in a series of Amazon S3 buckets. Create an AWS STS token vending machine that is integrated with the company's identity provider (IdP). When a user logs in, have the token vending machine attach an IAM policy that assumes the role that limits the user's access and/or upload only the data the user is authorized to access. Users can get credentials by authenticating to the token vending machine's website or API and then use those credentials with an S3 client.

Correct answer: D

Explanation

Option D is correct because using an STS token vending machine integrated with an IdP centralizes authorization management, bypassing the scalability limits of maintaining 1,000+ AWS accounts in S3 bucket policies or IAM roles. It allows users to access S3 directly using temporary credentials, which is highly scalable and handles throughput-intensive workloads (like simulations) much better than routing traffic through an EC2 application proxy (Option C). Options A and B are unscalable and highly complex to manage due to the sheer volume of accounts and changing nature of the organization.