What should a Solutions Architect check to determine why the database is not being updated?
Verify the AWS IoT Device Shadow service is subscribed to the appropriate topic and is executing the AWS Lambda function.
Verify that AWS IoT monitoring shows that the appropriate AWS IoT rules are being executed, and that the AWS IoT rules are enabled with the correct rule actions.
Check the AWS IoT Fleet indexing service and verify that the thing group has the appropriate IAM role to update DynamoDB.
Verify that AWS IoT things are using MQTT instead of MQTT over WebSocket, then check that the provisioning has the appropriate policy attached.
Explanations:
The AWS IoT Device Shadow service is primarily used for storing and retrieving the state information of devices, not for directly updating DynamoDB. Thus, verifying the Device Shadow’s subscription and execution of a Lambda function does not directly address the issue of DynamoDB updates.
This option addresses the critical components involved in message processing from AWS IoT Core to DynamoDB. It involves checking the AWS IoT rules to ensure they are executed properly and that the correct rule actions (such as writing to DynamoDB) are enabled. If the rules are not being executed, messages won’t be processed, leading to no updates in the database.
The AWS IoT Fleet indexing service relates to managing and searching device metadata, not the direct processing of messages sent to DynamoDB. While IAM roles are important for permissions, the primary issue here is not directly related to indexing or IAM roles but rather the execution of IoT rules.
This option addresses the communication protocol used by the devices (MQTT vs. MQTT over WebSocket), which is generally not the primary concern for database updates. While ensuring the correct policy is attached is essential, it is not the main reason for database update failures, as the critical link involves IoT rules and their execution.
I conclude that the answer is:
Verify that AWS IoT monitoring shows that the appropriate AWS IoT rules are being executed, and that the AWS IoT rules are enabled with the correct rule actions.