This topologying strategy relies on Erlang's built-in distribution protocol by using a .hosts.erlang file (as used by the :net_adm module).

Please see the net_adm docs for more details.

In short, the following is the gist of how it works:

File .hosts.erlang consists of a number of host names written as Erlang terms. It is looked for in the current work directory, the user's home directory, and $OTP_ROOT (the root directory of Erlang/OTP), in that order.

This looks a bit like the following in practice:

'super.eua.ericsson.se'.
'renat.eua.ericsson.se'.
'grouse.eua.ericsson.se'.
'gauffin1.eua.ericsson.se'.