Consider switching MDNS container for hostname container

[maggie44]

Considering the size and complexity of the MDNS container, and the fact that it isn't going to be needed by a lot of users, is it worth switching it out for the hostname container (https://github.com/balenablocks/hostname) as the default, and then let users add the MDNS if they require it? The hostname container will change the hostname to a specified name, which will then make the device accessible via the-specified-name.local. The only reason for then needing an additional MDNS is if that hostname is going to be changing, which is quite a niche use case.

Hostname container is around 10mb and MDNS is 200mb+. It is also uses less resources and exits when finished.

@nucleardreamer

[nucleardreamer]

So there are a couple differences using the MDNS container vs changing just the hostname

• Pro: Like you said, very small image size (and honestly we don't even have to use it, if we just call the hostname endpoint with the API)
• Con: Changing the hostname will persist across deployments, so it might be slightly unexpected experience for someone to run our docker-compose, push different software, and be stuck on the previous hostname (they will have to then use the hostname block or supervisor API to switch to something else).
• Con: Changing the hostname to get the new MDNS advertisement also requires a reboot of the avahi service to pickup the new change, which is usually done by just rebooting the device (or restarting the avahi service via systemctl on the hostOS).

The mdns-advertise container takes care of these cons by setting avahi to advertise programmatically and in a non-destructive way, but the container size is much bigger.

I think we can go either way for sure, as long as we know that there might be a potentially more bumpy experience using either the hostname block or just hitting the endpoint on the supervisor

[maggie44]

You're right about calling the endpoints rather than using the block, we had the endpoints already. It is added with a environment variable so if someone didn't want to change the hostname they can just remove the env variable from the compose. Makes it completely optional.