Authentication occurs between Erlang VMs (beam or beam.smp). epmd only handles port registration. Simply short-circuiting epmd is not extremely easy, and other approaches might be more appropriate to your actual need.
Unfortunately, epmd is not an option for the default distribution protocol (inet_tcp_dist) or for its SSL counterpart. There are two undocumented options that look like you can disable epmd (-no_epmd) or provide an alternative implementation (epmd_module). However, the dependency of the distribution protocols on epmd is hard-coded and does not depend on these options.
So you could:
- override the
erl_epmd module at the code server level (probably the dirtiest approach);
- provide an alternative distribution protocol which would copy (or call)
inet_tcp_dist except for the parts where erl_epmd is called. Mainly, you need to provide your own implementation of setup/5.
If you don't want the shell node to connect to epmd for registering its name, you will also need to override listen/1. In this case, you can pass -no_epmd to the command line.
Alternatively, you can connect to epmd to register the listening node in order to create a shell connection using the default protocol.
This approach is particularly useful if epmd lost track of a node (e.g. it was killed, unfortunately epmd is a single point of failure). To do so:
- Create a TCP connection to epmd and send a packet to register the lost node with its known port and name. Keep the TCP connection open or epmd will unregister the node.
- Connect a new shell to the lost node using the name used in previous step.
- You can then close the connection established in (1) and eventually re-register the lost node to epmd by calling
erl_epmd:register_node/2 (and sending well-crafted tcp_closed message if required).
