Question #674
An international logistics company uses a delivery tracking system on AWS. Drivers upload delivery proofs, such as timestamps and geotags, via SFTP to a single Amazon EC2 instance. Each handheld device saves files in directories named after the driver’s ID, with filenames corresponding to shipment tracking numbers. The EC2 instance enriches the files by querying a central database for shipment details before archiving them in Amazon S3. As the company grows, drivers experience connection timeouts, and the EC2 instance faces high CPU usage. The operations team implemented a cron job to restart the instance hourly, but some files are missing in S3, and the database updates are inconsistent. A solutions architect must design a scalable solution to ensure all files are archived and systems updated. The handheld devices cannot be modified. Which solution meets these requirements?
Create an AMI of the EC2 instance. Deploy an Auto Scaling group of EC2 instances behind a Network Load Balancer. Use Amazon EFS for shared storage and configure scaling based on CPU utilization.
Use AWS Transfer Family to create an SFTP server that stores files in Amazon EFS. Mount the EFS volume to the existing EC2 instance and update the processing script to reference the new file path.
Use AWS Transfer Family to create an SFTP server that stores files in Amazon S3. Configure S3 event notifications via Amazon SNS to invoke an AWS Lambda function for metadata enrichment and database updates.
Modify the handheld devices to upload files directly to Amazon S3. Use S3 event notifications with Amazon SQS to trigger an AWS Lambda function for processing and system updates.
Explanation
Option C is correct because:
- AWS Transfer Family provides a managed SFTP service, eliminating the EC2 instance as a bottleneck.
- Files are stored directly in Amazon S3, ensuring durability and scalability.
- S3 event notifications invoke a Lambda function for metadata enrichment and database updates, enabling serverless, parallel processing without EC2 reliance.
- This design ensures all files are processed (no missing data) and updates are consistent (no cron-related interruptions).
Other options fail because:
- A: Auto Scaling EC2 instances with EFS does not resolve SFTP scalability or stateful session issues.
- B: Using EFS with the existing EC2 instance retains the processing bottleneck and cron-related problems.
- D: Handheld devices cannot be modified, making direct S3 uploads impossible.
Key Points: Use managed services (Transfer Family, Lambda) for scalability; S3 event-driven workflows ensure reliability; avoid EC2 bottlenecks.
Answer
The correct answer is: C