Erlang (and Elixir) distribution without epmd, aka EPMDLESS

Allows to connect erlang nodes, via Erlang distribution and without epmd, using tcp or tls.

Requirements

Erlang >= 19.1

Configuration

Using TCP as transport protocol

{ epmdless, [
    {transport, tcp},
    {listen_port, 17012}
    ]
}.

Using TLS as transport protocol

{epmdless, [
    {transport, tls},
    {listen_port, 17012}
]}

And follow the instructions found in the OTP docs, Specifying SSL/TLS Options.

VM args

Erlang VM needs few extra flags on start to disable epmd daemon startup and override empd client callback module.

Minimal set of options: erl -proto_dist epmdless_proto -start_epmd false -epmd_module epmdless_client

Note: since epmd is disabled you need to populate epmd-client database manually. Check epmd_dist module API.

Example usage

(app2@host.local)1> epmdless_client:add_node('app1@host.local', 17012).
ok
(app2@host.local)2> epmdless_client:list_nodes().
[{'app1@host.local',{"host.local",17012}}]

Connecting to epmdless nodes

It's possible to connect to epmdless nodes using remsh. The distribution port can be provided via EPMDLESS_REMSH_PORT environmental variable.

Example usage:

EPMDLESS_REMSH_PORT=17012 erl -name local_node@127.0.0.1 -remsh epmdless_node@127.0.0.1 -setcookie <cookie> -proto_dist epmdless_proto -epmd_module epmdless_client -pa _build/default/lib/epmdless/ebin

Example project

Please also refer: https://github.com/oltarasenko/erlang_distribution_in_docker for an example of complete project running epmdless.

TLS example for Elixir

Here is a small project which shows how to setup EPMDLess with TLS for Elixir: https://github.com/oltarasenko/epmdless-elixir-example

(Please also see a discussion here: https://github.com/oltarasenko/epmdless/issues/11)