Move an IoT platform to IoT Core rules, DocumentDB, and Step Functions reports on S3

SAP-C02 By islever Editorial Last updated

Determine a new architecture for existing workloads. Determine opportunities for modernization and enhancements. Determine a strategy to improve overall operational excellence.

Short answer

ADE Use IoT Core with a rule invoking Lambda, migrate MongoDB to DocumentDB, and produce reports with Step Functions into S3.

Question

A company is migrating its on-premises IoT platform to AWS. The platform consists of the following components: • A MongoDB cluster as a data store for all collected and processed IoT data. • An application that uses Message Queuing Telemetry Transport (MQTT) to connect to IoT devices every 5 minutes to collect data. • An application that runs jobs periodically to generate reports from the IoT data. The jobs take 120-600 seconds to finish running. • A web application that runs on a web server. End users use the web application to generate reports that are accessible to the general public. The company needs to migrate the platform to AWS to reduce operational overhead while maintaining performance. Which combination of steps will meet these requirements with the LEAST operational overhead? (Choose three.)
  1. Create AWS Step Functions state machines with AUS Lambda tasks to prepare the reports and to write the reports to Amazon S3. Configure an Amazon CloudFront distribution that has an S3 origin to serve the reports Correct Answer
  2. Create an AWS Lambda function. Program the Lambda function to connect to the IoT devices. process the data, and write the data to the data store. Configure a Lambda layer to temporarily store messages for processing.
  3. Configure an Amazon Elastic Kubernetes Service (Amazon EKS) cluster with Amazon EC2 instances to prepare the reports. Create an ingress controller on the EKS cluster to serve the reports.
  4. Connect the IoT devices to AWS IoT Core to publish messages. Create an AWS IoT rule that runs when a message is received. Configure the rule to call an AWS Lambda function. Program the Lambda function to parse, transform, and store device message data to the data store. Correct Answer
  5. Migrate the MongoDB cluster to Amazon DocumentDB (with MongoDB compatibility). Correct Answer

Key Takeaways

Devices pushing to IoT Core removes the need for the application to poll them, an IoT rule invoking Lambda replaces the polling application entirely, and reports of 120 to 600 seconds fit comfortably inside Step Functions with Lambda tasks writing to S3 that CloudFront serves.

An on-premises IoT platform consists of a MongoDB data store, an application polling devices every five minutes over MQTT, a reporting job taking 120 to 600 seconds, and a public-facing web application. The migration must reduce operational overhead while maintaining performance.

Common mistake: Standing up an EKS cluster with an ingress controller to serve the reports. That reintroduces a Kubernetes control plane to operate, which is the opposite of reducing operational overhead, and it is unnecessary when the reports are static files in S3 behind CloudFront.

Expert Analysis

Why the Answer Is Correct

Each component maps to a managed service that removes infrastructure the team would otherwise run. Devices publish to AWS IoT Core, an IoT rule fires on each message and invokes a Lambda function that parses, transforms, and stores the data, which removes the on-premises application that was polling devices every five minutes, so D is correct. Amazon DocumentDB is MongoDB compatible, so the existing MongoDB workload moves to a managed database without changing the data model, which is why E is correct. The reporting jobs take between 120 and 600 seconds, which fits naturally in AWS Step Functions with Lambda tasks that prepare the report and write it to Amazon S3, and an Amazon CloudFront distribution with an S3 origin serves the reports to the public web application, which is why A is correct. The remaining MongoDB reporting and web tiers become S3 plus CloudFront rather than a web server the team hosts.

Why the Other Options Are Wrong

B: The Lambda function is programmed to connect directly to the IoT devices, which reverses the intended architecture. Ingest should be push-based through IoT Core with a rule invoking Lambda, and a temporary Lambda layer to hold messages is not the mechanism for durable ingestion, so this option does not replace the polling application correctly. C: An EKS cluster with an ingress controller to serve reports requires the team to operate and upgrade a Kubernetes control plane, which directly contradicts the requirement to reduce operational overhead, and static reports do not need an ingress controller at all.

Community Comment Notes

The community voted 100 to 0 for A, D, and E, and the top-voted comment broke down each choice, with Step Functions and Lambda handling the periodic report generation with minimal overhead, IoT Core and the rule handling device connections, and DocumentDB supporting the MongoDB workload. A second commenter independently confirmed the same three options, adding a nuance that Lambda is not the real answer for the device connection because IoT Core is.

Official Reference

https://docs.aws.amazon.com/iot/latest/developerguide/iot-rules-actions.html

This link opens the official vendor documentation in a new tab.

Community Votes

ADE
100%

100% of anonymous learners picked answer ADE. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 3 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 3

  1. awsaz 👍 7
    Step Functions and Lambda for Report Generation (A): AWS Step Functions and Lambda can manage the periodic jobs to generate reports with minimal operational overhead. By using Amazon S3 for storage and Amazon CloudFront for distribution, the solution provides scalability and reliability with minimal management. AWS IoT Core for MQTT Messaging (D): AWS IoT Core is a managed service that simplifies the connection and management of IoT devices. Using IoT rules and Lambda functions ensures efficient message processing and data storage with minimal overhead. Amazon DocumentDB for MongoDB Compatibility (E): Amazon DocumentDB is a managed database service compatible with MongoDB, which reduces the operational burden of managing a MongoDB cluster while maintaining performance and scalability.
  2. mifune 👍 2
    A - for preparing the reports and writing them to Amazon S3 | D - for handling connections from IoT devices | E - supporting MongoDB workloads.
  3. vip2 👍 1
    A, D and E meet all requirements clearly

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