AWS offers a variety of methods for monitoring both your IoT devices, as well as the IoT service and its calls. To get things started, let's first look at the simple device monitoring functionality provided by the AWS IoT dashboard itself. On the AWS IoT console page, select the Monitor option. Here, you can view a variety of graphs and data, such as the number of successful connections made to the AWS IoT service over the past hour, day, or week. You can even check the number of messages that were transmitted using either the MQTT or the HTTP protocol, as shown in the following screenshot:

You can also use the Monitor page to view the number of messages published, rules executed, and shadow updates performed.

In addition to this, you also have an option to enable logging for your AWS IoT service. To do so, select the Settings option from the navigation pane of the AWS IoT console. By default, logging of AWS IoT is disabled, however you can easily switch it on by selecting the Edit option provided under the Logs section. As messages from your IoT devices pass through the message broker and the rules engine, you can use the AWS IoT logs to process events and in turn, troubleshoot issues, both at the device as well as at the service's end.

You can choose between Debug (most verbose), Info, Warning, and Errors (least verbose) levels of verbosity, depending on your logging requirements.