Remote port forwarding on AWS EC2 does not open ports

Long story short, but by default SSH daemon does not open ports to the internets when you make remote port forwarding, e.g. allows to connect to ports from localhost only.
That’s smart, of course.

To allow connecting from the internets to your new ports you need to add changes to sshd config /etc/ssh/sshd_config:

Add there following line:

Now when you do

You will be able to make a request from outside 🙂

Cannot start observer from IEx shell on MacOS?

This means you don’t have wxWidgets installed.

I have Erlang installed with asdf tool, highly recommended using it for Erlang and Elixir installations.
So if you have Erlang already installed, uninstall it first:

Then you need to install wxWidgets:

Check whether you have wxWidgets installed correctly:

(it should show a version number)

After that you need to install Erlang back:

Voila, you can start observer from your IEx shell: