AWS Greengrass is a form of edge computing service that extends the cloud's functionality to your IoT devices by allowing data collection and analysis closer to its point of origin. This is accomplished by executing AWS Lambda functions locally on the IoT device itself, while still leveraging the cloud for management and analytics purposes.

How does this help a business? Well to start with, using AWS Greengrass you are now able to respond to locally generated events in near real time! With Greengrass, you can program your IoT devices to locally process and filter data and only transmit the important chunks back to AWS for analysis. This also has a direct impact on the costs as well as the amount of data transmitted back to the cloud.

Here's a brief look at a few of the necessary components that go into the workings of AWS Greengrass:

• Greengrass Core (GGC) software: The Greengrass Core software is a packaged module that consists of a runtime to allow executions of Lambda functions, locally. It also contains an internal message broker and a deployment agent that periodically notifies the AWS Greengrass service about the device's configuration, state, available updates, and so on. The software also ensures that the connection between the device and the IoT service is secure with the help of keys and certificates.
• Greengrass groups: A Greengrass group is a collection of Greengrass Core settings and definitions that are used to manage one or more Greengrass-backed IoT devices. The groups internally comprise a few other components, namely:
  • Greengrass group definition: A collection of information about your Greengrass group
  • Device definition: A collection of IoT devices that are a part of a Greengrass group
  • Greengrass group settings: Contains connection as well as configuration information along with the necessary IAM Roles required for interacting with other AWS services
  • Greengrass Core: The IoT device itself
• Lambda functions: A list of Lambda functions that can be deployed to the Greengrass Core.
• Subscriptions: A collection of a message source, a message target and an MQTT topic to transmit the messages. The source or targets can be either the IoT service, a Lambda function or even the IoT device itself.
• Greengrass Core SDK: Greengrass also provides an SDK which you can use to write and run Lambda functions on Greengrass Core devices. The SDK currently supports Java 8, Python 2.7, and Node.js 6.10.

With this key information in mind, let's go ahead and deploy our very own Greengrass Core on an IoT device.