How AWS IoT Greengrass works - AWS IoT Greengrass

How AWS IoT Greengrass works

The AWS IoT Greengrass client software, also called AWS IoT Greengrass Core software, runs on Linux-based distributions, such as Ubuntu or Raspberry Pi OS, for devices with ARM or x86 architectures. With AWS IoT Greengrass, you can program devices to act locally on the data they generate, run predictions based on machine learning models, and filter and aggregate device data. AWS IoT Greengrass enables local execution of AWS Lambda functions, Docker containers, native OS processes, or custom runtimes of your choice.

AWS IoT Greengrass provides pre-built software modules called components that let you easily extend edge device functionality. AWS IoT Greengrass components enable you to connect to AWS services and third-party applications at the edge. After you develop your IoT applications, AWS IoT Greengrass enables you to remotely deploy, configure, and manage those applications on your fleet of devices in the field.

The following example shows how an AWS IoT Greengrass device interacts with the AWS IoT Greengrass cloud service and other AWS services in the AWS Cloud.

        An overview of how an AWS IoT Greengrass device interacts with the AWS IoT Greengrass cloud service and other
          AWS services in the AWS Cloud.

Key concepts for AWS IoT Greengrass

The following are essential concepts for understanding and using AWS IoT Greengrass:

Greengrass core device

A device that runs the AWS IoT Greengrass Core software. A Greengrass core device is an AWS IoT thing. You can add multiple core devices to AWS IoT thing groups to create groups of Greengrass core devices.

Greengrass component

A software module that is deployed to and runs on a Greengrass core device. All software that is developed and deployed with AWS IoT Greengrass is modeled as a component. AWS IoT Greengrass provides pre-built public components that provide features and functionality that you can use in your applications. You can also develop your own custom components, on your local device or in the cloud. After you develop a custom component, you can use the AWS IoT Greengrass cloud service to deploy it to single or multiple core devices. You can create a custom component and deploy that component to a core device. When you do, the core device downloads the following resources to run the component:

  • Recipe: A JSON or YAML file that describes the software module by defining component details, configuration, and parameters.

  • Artifact: The source code, binaries, or scripts that define the software that will run on your device. You can create artifacts from scratch, or you can create a component using a Lambda function, a Docker container, or a custom runtime.

  • Dependency: The relationship between components that enables you to enforce automatic updates or restarts of dependent components. For example, you can have a secure message processing component dependent on an encryption component. This ensures that any updates to the encryption component automatically update and restart the message processing component.

For more information, see Manage AWS IoT Greengrass components.


The process to send components and apply the desired component configuration to a destination target device, which can be a single Greengrass core device or a group of Greengrass core devices. Deployments automatically apply any updated component configurations to the target and include any other components that are defined as dependencies. You can also clone an existing deployment to create a new deployment that uses the same components but is deployed to a different target. Deployments are continuous, which means that any updates you make to the components or the component configuration of a deployment automatically get sent to all destination targets. For more information, see Deploy AWS IoT Greengrass components to devices.

AWS IoT Greengrass Core software

The superset of all AWS IoT Greengrass software that you install on a core device. AWS IoT Greengrass Core software comprises the following:

  • Nucleus: This required component provides the minimum functionality of the AWS IoT Greengrass Core software. The nucleus manages deployments, orchestration, and lifecycle management of other components. It also facilitates interprocess communication between AWS IoT Greengrass components locally on an individual device. For more information, see Greengrass nucleus.

  • Optional components: These configurable components are provided by AWS IoT Greengrass and enable additional features on your edge devices. Depending on your requirements, you can choose the optional components that you want to deploy to your device, such as data streaming, local machine learning inference, or a local command line interface. For more information, see AWS-provided components.

You can upgrade your AWS IoT Greengrass Core software by deploying new versions of your components to your device.

Features of AWS IoT Greengrass

AWS IoT Greengrass Version 2 consists of the following elements:

  • Software distributions

    • The Greengrass nucleus component, which is the minimum installation of the AWS IoT Greengrass Core software. This component manages deployments, orchestration, and lifecycle management of Greengrass components.

    • Additional optional components provided by AWS that integrate with services, protocols, and software.

    • The AWS IoT Device SDK which contains the interprocess communication (IPC) SDK.

    • The Stream Manager SDK.

  • Cloud service

    • AWS IoT Greengrass V2 API

    • AWS IoT Greengrass V2 console

AWS IoT Greengrass Core software

You can use the AWS IoT Greengrass Core software that runs on your edge devices to do the following:

You configure and manage Greengrass core devices through AWS IoT Greengrass APIs where you create continuous software deployments.

For more information about supported platforms, requirements, and downloads, see Setting up AWS IoT Greengrass core devices.

By downloading this software, you agree to the Greengrass Core Software License Agreement.