When I tried running multiple notes before I used the Erlang :peer module.

Here’s a few snippets from a semi-defunct unreleased project I have:

    {:ok, node} =
      :peer.start_link(%{
        host: :localhost,
        name: 'peer_node',
        args: peer_args()
      })

    IO.puts("DONE Starting peer node!")
    add_code_paths(node)
    ensure_applications_started(node)

  defp add_code_paths(node) do
    rpc(node, :code, :add_paths, [:code.get_path()])
  end

  @apps_to_start [
    # :iex,
    :logger,
    # :file_system,
    # :jason,
    :erlexec,
    :runtime_tools,
    # :inets,
    :stdlib,
    :crypto,
    # :hex,
    :elixir,
    # :public_key,
    # :gviz,
    # :mix,
    # :gettext,
    :kernel,
    :ssl,
    :compiler
    # :asn1,
  ]

  defp ensure_applications_started(node) do
    rpc(node, Application, :ensure_all_started, [:mix])
    rpc(node, Mix, :env, [Mix.env()])

    # for {app_name, _, _} <- Application.loaded_applications() do
    #   rpc(node, Application, :ensure_all_started, [app_name])
    # end
    for app_name <- @apps_to_start do
      IO.inspect(app_name, label: "starting app_name")

      rpc(node, Application, :ensure_all_started, [app_name])
      |> IO.inspect(label: "started #{inspect(app_name)}")
    end
  end

  defp rpc(node, module, function, args) do
    :rpc.block_call(node, module, function, args)
  end

  defp peer_args do
    Enum.join(
      [
        "-loader inet -hosts 127.0.0.1",
        "-setcookie #{:erlang.get_cookie()}",
        # "-env MIX_BUILD_ROOT /tmp/gviz_build"
      ],
      " "
    )
    |> to_charlist()
  end

@LostKobrakai All the debugging above is for the :peer approach in PeerNode
@D4no0 instead of ‘best’ perhaps I should have said ‘easiest’ so far

I’m learning and trying to understand more. If both :peer and CLI approaches start a new beam instance, why is one considered better/worse?

Or you can do what Livebook does. Use a separate BEAM node.

Not sure if it’s the problem, but note that Node.spawn expects a function as its second argument and you’re trying to pass the result of Code.require_file there instead. Maybe you need a wrapping fn -> ... end?

Node.spawn/2 is a low-level function, try instead :erpc.call/2, that will handle redirection of errors and output.