I have two repos, and just recently we switched to myxql from mariaex. Since then, when starting the application, the second repo errors out, and seems to use the IP address/hostname of the machine network I am instead of what is supplied in the config.

Surely, there is a tiny mistake I am overlooking, but it is driving me mad.

As a first hint: how would ecto/myxql be able to get a hold of that ip?

For instance, on my local machine, it goes ahead and fetches my public ip (behind ISP router here). Or for the actual app running docker, it has the public IP of the host machine, instead of the actual DB host ip, as configured in the settings. The settings itself seem to be OK, we inspected the sys.config file inside the docker container.

Maybe our supervision tree for the application is not ok, but it worked just fine with mariaex.

    children = [
      # Start the Ecto repository
      supervisor(App.Repo, []),
      supervisor(App.RepoDuo, []),
      # Start the endpoint when the application starts
      supervisor(App.Endpoint, []),