I’m playing with Home Assistant and I started with their Home Assistant Core Docker container image. After a week of use, I understood some of the benefits of going with their full Home Assistant Operating System. If I like Home Assistant enough to keep it around I will likely dig up one of my old computers and make it a dedicated machine. In the meantime, I will continue evaluating Home Assistant by running Home Assistant Core in a container. The documentation even gave us a
docker-compose.yml file all ready to go:
version: '3' services: homeassistant: container_name: homeassistant image: "ghcr.io/home-assistant/home-assistant:stable" volumes: - /PATH_TO_YOUR_CONFIG:/config - /etc/localtime:/etc/localtime:ro restart: unless-stopped privileged: true network_mode: host
This is fairly straightforward, but I had wondered about the last two lines.
First question: why does it need to run in privileged mode? I couldn’t find an answer in Home Assistant documentation. And on the other end, official Docker compose specification just says:
privilegedconfigures the service container to run with elevated privileges. Support and actual impacts are platform-specific.
So the behavior of this flag isn’t even explicitly defined! For the sake of following directions, my first launch of Home Assistant Core image specified true. Once I verified it was up and running, I took down the container and brought it back up without the flag. It seemed to work just fine.
One potential explanation: upon initial startup, Home Assistant needed to create a few directories and files in the mapped volume
/config. Perhaps it needed the privileged flag to make sure it had permissions to create those files and set their ownership properly? If so, then I only needed to run with the flag for first execution. If not, then that flag may be completely unnecessary.
Second question: why does it need to run in host network mode? Unlike privileged, network mode is much better defined and host means “gives the container raw access to host’s network interface”. I tried running Home Assistant Core with and without this flag. When running without, Home Assistant could no longer automatically detect ESPHome nodes on the network. Apparently auto-discovery requires running in host network mode, and it’s a big part of the convenience of ESPHome. In order to avoid the tedium of getting, tracking, and typing in network addresses, I shall keep this line in my Docker compose file while I play with Home Assistant Core.