Erlang distributed

• Distributed connection epmd
• Message transmission

Reference

Basics

• External Term Format
• Erlang Processes
• EPMD Protocol
• LYSE distribunomicon

Node connection process

• [Erlang 0123] Erlang EPMD

Introduction to basic knowledge of node connection

• Distributed Erlang

Distributed related code guide

• [Erlang14] How to simulate various failure situations after node interconnection?

Node connection establishment process

• Incarnation problem caused by Erlang node restart

Node process communication, after reconnection, the previous pid invalidation problem description

Message

• Erlang Message Passing

Basic inter-process message transmission

• Boost message passing between Erlang nodes

Processing of large message transmission scenarios between nodes, using round-robin sending solution, business-unfriendly, not recommended

• [erlang send analysis and parameter meaning

Principles of message sending

• Message transmission characteristics

Non-blocking, ordered, same-node use refc binary to process big data

Binary

• [Erlang20] Let’s conquer Binary
• Representation and implementation of Erlang data types (5) - binary
• Erlang: high memory usage for processing list of binary parts

Example

• Start

erl -name bb@127.0.0.1

erl -name aa@127.0.0.1
net_kernel:connect_node('bb@127.0.0.1').

• You can view the communication data between nodes

net_kernel:i().
Node                 State   Type         In      Out Address
bb@127.0.0.1         up      normal      728      549 127.0.0.1:52660
Total                                    728      549
ok

net_kernel:node_info('bb@127.0.0.1').
{ok,[{owner,<0.8287.0>},
     {state,up},
     {address,{net_address,{{127,0,0,1},52660},
                           "127.0.0.1",tcp,inet}},
     {type,normal},
     {in,721},
     {out,544}]}

• sys_dist ets table stores the node information of the connection

ets:tab2list(sys_dist).
[{connection,'bb@127.0.0.1',
             {1,#Ref<0.4062885077.249954305.136891>},
             up,<0.8287.0>,#Port<0.14>,undefined,
             {net_address,{{127,0,0,1},52660},"127.0.0.1",tcp,inet},
             [],normal}]

• epmd names

epmd -names
epmd: up and running on port 4369 with data:
name bb at port 52660
name aa at port 52589

Others

• Get information through sys_dist to monitor the communication volume between nodes
• Get the port of the current node connecting to the target node

inet:port(#Port<0.14>).
{ok,52669}