This section presents the basic terms used throughout the documentation.
Accepted device - An authorized device that can connect to the Mender Server and receive software updates.
Add-on (also Mender Add-on)- An optional extension to Mender for supporting use cases beyond core OTA updates features, e.g. Remote terminal. Install Mender first, before installing any add-ons
Application update - An update which is not an Operating System update.
Artifact - An archive containing everything needed for an update of a device, including the Artifact Payload itself and metadata such as signatures. See the documentation on Artifact for more information.
Artifact Name - A human-readable string uniquely describing an Artifact, used by the UI and Server-side API for identification purposes.
Artifact Payload - Actual data installed on a device, stored inside a Mender Artifact. It could be a rootfs image, package, container, or other. See the documentation on Artifact for more information.
Authentication Set - A combination of an identity and public key for a device, determining if a given device can check for- and apply software updates from the Mender Server. A given device identity can have multiple Authentication sets and each can be in one of the following states:
Binary delta - The binary difference between two Operating System images. See the documentation on Delta updates for more information.
Board integration - The low-level integration required to enable Operating System updates with Mender on a board. Often includes OS bootloader and storage integration and requires customization based on the hardware and OS.
Component - Part of a System. Components are the logical units that are updated during a System update. The System device (i.e. a device running Mender Orchestrator) and all dependent devices are considered Components of the System. Dependent devices may be either physical boards connected to the System device (for example, a control unit connected via CAN) or logical parts of the application stack. See the documentation on Orchestrating updates for more information.
Compatible type - The type of a device, a Component or System used to ensure compatibility between the hardware and software. See the documentation on Artifact for more information.
Container update - An Application update for containerized software running on the devices.
Deployment - The process of delivering software to devices. It consists of at least a group of devices and an Artifact name.
Device, Mender Client Device - A single unit that is able to connect to the Mender Server, usually an independent product. Represented on the server by its identity and authentication data.
Device-side API - The collection of APIs exposed by the Mender components running on the device. The Device-side API constitutes the only public programmatic interface of the Mender Client. It is a thin layer that receives messages over D-Bus, processes them, transmits them to the Mender Client, receives the results from the client, and transmits a response on the D-Bus.
Device ID - A single string uniquely identifying a device in the Mender server, used in Server-side APIs to specify an individual device. See the documentation on device Identity for more information.
Device tier - A classification that describes the class of an authenticated device. There are three device tiers:
mender-mcu, typically with constrained resourcesDevice tiers affect artifact size limits, polling intervals, deployment restrictions, and device count limits in your plan. See the documentation on Device tiers for more information.
Device type - The type of device, used to ensure compatibility between the hardware and software. A more generic term Compatible type (see above) is now preferred. See the documentation on Artifact for more information.
Identity (Mender Client Device) - A set of immutable, human-readable attributes that uniquely identify a Mender Client Device. See the documentation on Device Identity for more information.
Identity (Component) - In the context of a System, an attribute provided by the Component’s Interface that uniquely identifies it. This attribute may change (for example, when a Component is physically replaced), making the change visible. See the documentation on Identity query for more information.
Interface - Used in the context of a System. An Interface used for updating Components. See the documentation on Interface Protocol for more information.
Inventory - A set of attributes of a Mender Client Device or a Component. See the documentation on Inventory for more information.
Mender Client - A collective term for the Mender Update service, which consists
of two service components, mender-auth and mender-update.
Mender Connect - A user space application providing the add-ons framework, as well as implementation of particular add-ons which you can enable or disable as per configuration. It integrates with the Mender Client over a well-defined and portable Device-side API.
Mender Hub Integration(s) - A contribution on Mender Hub of a Mender Board integration for a specific board.
Mender Gateway - An application that enables managing and deploying OTA updates to devices on the local network. The gateway acts as a proxy with the ability to understand and serve client requests locally.
Mender Server - An application implementing the Server-side Mender API, and the web UI, providing updates to devices.
mender-auth, mender-auth Client - A user space application running on a
device which provides authentication to the Mender Server for other
applications. This application is required by other applications that
communicate with the Mender Server.
mender-update, mender-update Client - A user space application installing
updates to a device it is running on. It uses the the mender-auth client
service and Mender Server-side API to connect to the Mender Server, get the
artifacts, report inventory, log the progress and status of the installations.
Operating System update - An update which replaces the operating system's filesystem thanks to the A/B partitioning schema. The Mender Client writes a new filesystem image to the inactive partition and updates the bootloader configuration to flip the active and inactive partition.
Organization - A single customer environment in the Mender Server. Also known as a Tenant. Note that multi-tenancy is only supported in Mender Enterprise.
Pending device - A device that has already sent an authorization request to the Mender Server and is not yet authorized through preauthorization or user authorization.
Preauthorized device - A device given by authorization set, that will change into "accepted" state automatically when it requests authorization.
Reference board - A board officially supported by Mender, used as a reference when porting to new boards.
Rejected device - A device that has already sent an authorization request to the Mender Server, which has been explicitly rejected by the user. A device in this state is not allowed to communicate with the Mender Server and will not receive any updates.
Release - A set of one or more Artifacts with the same Artifact name. Used by the Mender Server to assign the right Artifact to a given Device based on software and hardware compatibility.
Rootfs-image update module - One of the standard extensions to
mender-update (part of the Mender Client) which offers full root filesystem
updates using a dual partition setup.
Server-side API - The collection of HTTP-based APIs exposed by the Mender Server. They include management end-points, consumed by users and the UI, device end-points, consumed by the Mender components running on the devices, and internal end-points.
Service Provider tenant - A special tenant which can create and manage child tenants, e.g., different divisions or teams in the same organization or customers managed by a service provider business partner. Service Provider tenants are an Enterprise feature.
Signing system - A separated and not publicly accessible part of an IT infrastructure used to cryptographically sign Artifacts or other items, in the asymmetric encryption model.
System device - Main Component of a System. A Mender Client Device that is running Mender Orchestrator. See the documentation on Orchestrating updates for more information.
Tenant - See Organization.
Update Module - An extension to the Mender Client for supporting a new type software update, such as a package manager, container or bootloader.
Topology - A YAML file defining the Components of a System. Provisioned alongside new Systems, it specifies what Components are present and how they can be updated. See the documentation on Topology for more information.
Manifest - A YAML file defining Software versions for a given System. Maps Artifacts to Component types and controls update strategy. See the documentation on Manifest for more information.
System - Consists of one Device running Mender Orchestrator and one or more Components. A System exists when a Device has a System type and corresponding Topology.