Clusterable

Help cluster Elixir nodes, ideal for using with iex and mix, not suitable for using with releases.

With Clusterable, you can forget about special settings/configurations for clustering. And you no longer need to start Elixir/Erlang with --sname or --name.

Not for releases

It’s mainly for docker users (like me), and those who don’t use releases. It won’t work in releases, as :net_kernel will already be started, and the cookie will already be set.

What is it good for?

It’s good for clusters that don’t have a fixed number of nodes, and you don’t want to manage an orchestration script/tool that assigns names/IPs before nodes boot. i.e. it’s for auto scaling clusters and lazy devs :+1:

Installation

It’s available in Hex, the package can be installed by adding clusterable to your list of dependencies in mix.exs:

def deps do
  [{:clusterable, "~> 0.2"}]
end

Example Config

config :clusterable,
  cookie: :my_cookie,
  app_name: "my_app"

Example Usage

Start Elixir with --erl or ELIXIR_ERL_OPTIONS:

-proto_dist Elixir.Clusterable.EPMD.Service
-epmd_module Elixir.Clusterable.EPMD.Client"

e.g. iex --erl "-proto_dist ... -epmd_module ..." -S mix

Add Clusterable to a supervision tree as a non-permanent worker, i.e. transient or temporary

worker(Clusterable, [], restart: :transient)

For Elixir 1.5+, simply add Clusterable to your children list, its child_spec sets the correct restart strategy already.

If you are playing with it in IEx, you can start it manually

Clusterable.start_link

Testing with Docker 1.10+

• clone Clusterable project
• in the project dir, run the commands below:

docker build -t clusterable .
docker network create -d bridge peer

# open shell 1
docker run --rm -it --network peer --network-alias peer clusterable
iex> Clusterable.start_link

# open shell 2, do the same
docker run --rm -it --network test --network-alias peer clusterable
iex> Clusterable.start_link