Move an IoT platform to IoT Core rules, DocumentDB, and Step Functions reports on S3
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.)
Community Votes
100% of anonymous learners picked answer ADE. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
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.
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.
Community Discussion (3 comments)
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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
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