To avoid confusion, here is a glossary of terms that we use for UBOS.


On UBOS, an app is a software application that provides direct value to the user without any further additions, integrations or customizations. Apps generally have software dependencies only on packages provided as part of UBOS.

UBOS apps are typically web apps, i.e. apps whose primary user interface is presented using a web browser. Some examples for UBOS apps are:

  • ​Wordpress (blogging and publishing)
  • A house monitoring application, accessible over http or https.

Apps can generally be installed more than one on the same device, in multiple app configurations. Middleware components (e.g. databases) are not considered apps because the user generally does not directly interact with them.


An accessory on UBOS is a software module that adds to or modifies the functionality of an app. Accessories includes things such as plugins, themes, skins, extensions, add-ons and the like. UBOS uses the term “accessory” as a consistent, common term for all of those.

Examples for what UBOS would call accessories are:

  • themes or skins that change the graphic layout of Wordpress;
  • a module that requires users to fill out a captcha before they can register for a wiki;
  • a module that adds a Facebook Like button to an app.
App configuration

The installation of an app at a particular Site (aka virtual host) with a certain context path. For example, if a device runs two virtual hosts and, and Wordpress is installed at, at and at the root of, the host runs three Wordpress App Configurations. If can also run several other App Configurations for other apps. Each of the App Configuration usually has its own database, data storage, list of accessories and customization parameters.

App Configurations are identified through appconfigids.


UBOS identifies each app installed at a particular site with a unique identifier, such as aa6b76deec72fc2e86c812372e5922b9533ca2d58. UBOS commands that refer to a particular installation of an app generally require that the corresponding appconfigid is specified. This is particularly important if a device contains several installations of the same app at different virtual hostnames, for example. (See also siteid.)

To determine an appconfigid, execute:

> sudo ubos-admin listsites

Because the appconfigid is long and unwieldy, you can alternatively use only its first few characters, as long as they are unique on your host and you append three periods at the end.

For example, if there is no other app installed on your device whose appconfigid starts with aa, you can use aa... as a shorthand.

Arch Linux
A rolling-release GNU/Linux distribution developed at and ported to various ARM architectures at .
Customization point
A variable whose value can be customized by the user. For example, an app might allow the user to configure the title of the app upon installation. In this case, it declares a customization point title in its manifest JSON. The user can specify a value for the customization point in their Site JSON. That way, each installation of the app can have a different title, for example.
The site through which UBOS packages are distributed. The UBOS depot hosts several repositories in several release channels.
Any physical or virtualized computer running UBOS. This could be a Raspberry Pi, an x86 server, an instance on Amazon EC2 or a virtual machine on your desktop with virtualization software such as VirtualBox or VMWare.
See Shepherd.
Indie application
A web application that can be installed on hardware, or on a hosting provider of the user’s choosing. Contrast with a typical website were the user does not have this choice.
Indie IoT
The part of the Internet of Things that is independently owned and operated. Contrast with “Overlord IoT”. For example, the NEST thermostat is not part of the Indie IoT (Google hermetically seals the device, and siphons all the data before the “owner” of the device sees it), while a similar product that kept data local and allowed the owner to modify it at will would be part of the Indie IoT.
A new certificate authority that provides free SSL/TLS certificates accepted by most browsers. See
Multicast DNS (mDNS)
The multicast DNS system allows users to use certain human-friendly hostnames (like ubos-pc.local) on local-area networks without having to configure DNS servers.
Network Configuration
In UBOS, a network configuration is a set of active network interfaces, their configuration, and the configuration of associated services such as DNS, firewall, and the like.
A set of code components that logically belong together. For example, the wordpress package contains all code specific to Wordpress, but no code that might also be used by other packages.
Personal server
A computer that is primarily accessed over the network, and fully owned by the person who purchased it. For example, a Raspberry Pi running a web application that allows users to control the lights in their house from a web browser would be a Personal Server. As a counter-example, if users could control the lights in their house from a web browser connecting to some vendor’s website, this may involve a “server” in their house, but not one they control.
The build script for creating a UBOS or Arch Linux package. The Arch Linux wiki has a good description.
Release channel
A maturity level for an UBOS release. See also UBOS build and release process. UBOS is developed on channel red, which contains bleeding-edge, untested “alpha” quality code. Channel yellow corresponds to traditional “beta” code, while green is the production channel. End users almost always will subscribe to green, while developers will do most of their work on red and yellow.
A collection of packages. For example, the UBOS tools repository contains tools useful to the developer, but not to the end user. By default, system do not use the tools repository, but developers can easily add it to take advantage of the provided development tools.
Rolling release
Most operating system distros release a major release every couple of years with major new features, and then minor updates on a regular basis. A distro using rolling releases, such as UBOS, provides updates on a continuous basis without major jumps. This allows user devices to be more up-to-date more of the time, and avoids often error-prone major upgrades.
The UBOS shepherd is the person who administers one or more devices running UBOS. These devices are called the flock. The Shepherd uses a USB stick, called the UBOS Staff, to configure the devices in the flock by booting the devices while the Staff has been inserted into the device’s USB port. Configuration information picked up by the UBOS device will remain valid until the Shepherd reboots the device with the Staff present again.
Short for website; all the apps and functionality at the same hostname, e.g. virtual host. Sites are referred to by siteids.

A JSON file that contains all meta-data about a Site, including hostname, which apps are installed at which relative URLs, and so forth. To obtain the Site JSON for a particular installed site with siteid <siteid>, execute:

> sudo ubos-admin showsite --json --siteid <siteid>

To deploy or update a deployed site to the configuration contained in a Site JSON file called <site-json-file>, execute:

> sudo ubos-admin deploy --file <site-json-file>

UBOS identifies sites with a unique identifier, such as s4100f3ed79b845dc04a974c0144f5c5b2f81face. UBOS commands that refer to a particular site generally require that the site’s siteid is specified. (See also appconfigid.)

To determine a site’s siteid, execute:

> sudo ubos-admin listsites

Because the siteid is long and unwieldy, you can alternatively use only its first few characters, as long as they are unique on your host and you append three periods at the end.

For example, if there is no other site installed on your host whose siteid starts with s41, you can use s41... as a shorthand.

Many commands also accept the current hostname of the site instead of the siteid.

See Shepherd.
UBOS manifest json
A JSON file that contains meta-data about an app or accessory beyond the meta-data provided by PKGBUILD.