The Supervisor

On Home Assistant OS, Home Assistant Core doesn't run by itself. The Supervisor runs it. The Supervisor starts Core, updates it, backs it up, and restores it. It also runs apps, and a few helpers of its own.

Core, every app, every helper, and the Supervisor itself run as Docker containers.

• The Supervisor is a Python program, in the home-assistant/supervisor repository.
• It runs Core, apps, and plugins as containers. How they are networked is in what the Supervisor runs.
• It has a REST API, at http://supervisor. Core, apps, and the command line use it.
• It makes backups, installs updates, and checks the system for problems.

Next to Core and the apps, the Supervisor runs a few plugins of its own: for DNS, audio, the ha command line, multicast discovery, and a status page that keeps working when everything else is down. What the Supervisor runs lists every container, with its name and network.

• The Supervisor API: Core, apps, and the ha command line talk to the Supervisor over a REST API at http://supervisor. What a caller may do depends on its role. See the Supervisor API, and how Core uses it in the connection with Core.
• Ingress: shows the web interface of an app inside Home Assistant, behind its login, without opening a port. See ingress.
• Backups and updates: the Supervisor backs up Core, apps, and folders, and installs new versions from version.home-assistant.io. See how the Supervisor works.
• Keeping the system healthy: it checks the system all the time, and what it finds shows up as repair issues. See the resolution center.

• How the Supervisor works: how it starts, jobs, and the code layout
• Plugins: the DNS, audio, CLI, multicast, and observer containers
• Develop the Supervisor: run and test your changes
• How apps work: the Supervisor from an app's point of view

• Start with your first contribution to the Supervisor. It runs a complete system on your own machine.
• Building an app instead? Head to your first app in the Apps area.