Hass.io is a Docker-based system for managing your Home Assistant installation and related applications. The system is controlled via Home Assistant which communicates with the Supervisor. The Supervisor provides an API to manage the installation. This includes changing network settings or installing and updating software.

Installation instructions can be found at https://home-assistant.io/hassio.

The development of the supervisor is a bit tricky. Not difficult but tricky.

• You can use the builder to build your supervisor: https://github.com/home-assistant/hassio-builder
• Go into a HassOS device or VM and pull your supervisor.
• Set the developer modus with cli hassio supervisor options --channel=dev
• Tag it as homeassistant/xy-hassio-supervisor:latest
• Restart the service like systemctl restart hassos-supervisor | journalctl -fu hassos-supervisor
• Test your changes

Small Bugfix or improvements, make a PR. Significant change makes first an RFC.