# primary machine running insidious and postgresql
# have user run 'psql "CREATE USER remoteuser ... from host ... with password ... etc..."'
{
  networking.hostName = "primary.machine";
  services.insidious = {
    enable = true;
    database = {
      createLocally = true;
    };
  };
}

# extra machines running insidious
{
  services.insidious = {
    enable = true;
    database = {
      host = "primary.machine";
      user = "remoteuser";
      passwordFile = "/path/to/password";
    };
  };
}