erlang-distribution

Erlang Distribution

Introduction

Erlang's built-in distribution enables building clustered, fault-tolerant systems across multiple nodes. Processes on different nodes communicate transparently through the same message-passing primitives used locally. This location transparency makes distributed programming natural and straightforward.

The distribution layer handles network communication, serialization, and node connectivity automatically. Nodes discover each other through naming, with processes addressable globally via registered names or pid references. Understanding distribution patterns is essential for building scalable, resilient systems.

This skill covers node connectivity and clustering, distributed message passing, global name registration, distributed supervision, handling network partitions, RPC patterns, and building production distributed applications.

Node Connectivity

Nodes connect to form clusters for distributed computation and fault tolerance.

%% Starting named nodes
%% erl -name node1@hostname -setcookie secret
%% erl -sname node2 -setcookie secret

%% Connecting nodes
connect_nodes() ->
    Node1 = 'node1@host',
    Node2 = 'node2@host',
    net_kernel:connect_node(Node2).

%% Check connected nodes
list_nodes() ->
    Nodes = [node() | nodes()],
    io:format("Connected nodes: ~p~n", [Nodes]).

%% Monitor node connections
monitor_nodes() ->
    net_kernel:monitor_nodes(true),
    receive
        {nodeup, Node} ->
            io:format("Node up: ~p~n", [Node]);
        {nodedown, Node} ->
            io:format("Node down: ~p~n", [Node])
    end.

%% Node configuration
start_distributed() ->
    {ok, _} = net_kernel:start([mynode, shortnames]),
    erlang:set_cookie(node(), secret_cookie).

%% Hidden nodes (for monitoring)
connect_hidden(Node) ->
    net_kernel:connect_node(Node),
    erlang:disconnect_node(Node),
    net_kernel:hidden_connect_node(Node).

%% Get node information
node_info() ->
    #{
        name => node(),
        cookie => erlang:get_cookie(),
        nodes => nodes(),
        alive => is_alive()
    }.