To make system timezone configurable, we need to have /etc/localtime writable, and it must be possible to atomically create a symlink from this place, which means the whole parent folder must be writable. We don't have /etc writable and can't use the usual bind mount for this. Latest Systemd v258 has patch that allows setting an environment variable that sets where the localtime should be written. This can be persisted in the overlay partition, with a symlink from /etc/localtime leading there, finally pointing to the actual zoneinfo file. If the symlink doesn't exist, create it by hassos-overlay script (it's not really needed as UTC is the default, but Systemd does the same if you change from non-UTC timezone back to UTC). Also disable BR2_TARGET_LOCALTIME, so /etc/localtime and /etc/timezone (the latter is only informative and non-standard) are not written by the tzdata package build.
Home Assistant Operating System
Home Assistant Operating System (formerly HassOS) is a Linux based operating system optimized to host Home Assistant and its Add-ons.
Home Assistant Operating System uses Docker as its container engine. By default it deploys the Home Assistant Supervisor as a container. Home Assistant Supervisor in turn uses the Docker container engine to control Home Assistant Core and Add-Ons in separate containers. Home Assistant Operating System is not based on a regular Linux distribution like Ubuntu. It is built using Buildroot and it is optimized to run Home Assistant. It targets single board compute (SBC) devices like the Raspberry Pi or ODROID but also supports x86-64 systems with UEFI.
Features
- Lightweight and memory-efficient
- Minimized I/O
- Over The Air (OTA) updates
- Offline updates
- Modular using Docker container engine
Supported hardware
- Nabu Casa
- Raspberry Pi
- Hardkernel ODROID
- Asus Tinker Board
- Generic x86-64 (e.g. Intel NUC)
- Virtual appliances
See the full list and specific models here
Getting Started
If you just want to use Home Assistant the official getting started guide and installation instructions take you through how to download Home Assistant Operating System and get it running on your machine.
If you're interested in finding out more about Home Assistant Operating System and how it works read on...
Development
If you don't have experience with embedded systems, Buildroot or the build process for Linux distributions it is recommended to read up on these topics first (e.g. Bootlin has excellent resources).
The Home Assistant Operating System documentation can be found on the Home Assistant Developer Docs website.
Components
- Bootloader:
- Operating System:
- Buildroot LTS Linux
- File Systems:
- Container Platform:
- Docker Engine for running Home Assistant components in containers
- Updates:
- RAUC for Over The Air (OTA) and USB updates
- Security:
- AppArmor Linux kernel security module
Development builds
The Development build GitHub Action Workflow is a manually triggered workflow which creates Home Assistant OS development builds. The development builds are available at https://os-artifacts.home-assistant.io/index.html.
