[erlang-questions] Programming Erlang: Chap 18, Websockets

[ok@REDACTED]

Joe Armstrong wrote feelingly about the problems of the "same"
software not working in (very subtly) different environments.

As I understand it, this is one of the driving forces behind
the application = VM approach using Docker and the like:
make a VM containing the things your application needs and
as little else as you can manage, and then never change it.
If you want a new version of the application, make a new VM.