rdebug | Rdebug — Real Debugger | Code Inspection library

It seems your remoteWorkspaceRoot it's pointing to your local machine, the debugger needs to know what file should he watch to break inside the docker container

For example, if inside your docker container, your project is on "/app", you should change your remoteWorkspaceRoot variable to "/app"

In console you should see

Solution found:

So this line in the original tutorial is incorrect

Looks like you have some funny encoding on line 3 of your start.sh file that isn't being interpreted as a comment, which is likely causing the commented line to actually start a server.

When the bundle exec rdebug-ide --host 0.0.0.0 --port 1234... command executes, it throws the 'port in use' error because there is already a server running on port 1234 from the first command.

If you remove the commented-out lines you should be good to go.