Just leaving this here because it took hours for me to figure out (I've never used docker before until 2 days ago). And I didn't see a clear guide on here regarding RCON.
To use RCON you need to enable it and add the port mapping for it:
1) opening up the console to the minecraft container by clicking on the container icon and selecting "console" (I used BASH for the terminal)
2) cd config/minecraft
3) nano server.properties
4) edit the value of "enable-rcon" to "true" and "rcon.password" to a SECURE password (I cannot stress this enough). Touch nothing else.
5) CTRL X to save
6) Click on the container icon and select "edit"
7) Scroll to the bottom to add another Port with 25575 has the Host and container port as a TCP connection.
8 ) Restart the container.
For extra security, I suggest not opening up that port and only access it from an app in your network. The last thing you want is someone with the power to edit your server with a few console commands. And I know it's taboo to hard edit the content of a container, but I honestly didn't know what else to do. I needed RCON enabled in order for my bot to work with it.
If there's a better, more secure, solution. I'm open to it.
