peerjs-server | PeerServer helps establishing connections between PeerJS

Okay, I got it to work. Here's what I've done to get everything working on port 9000.

In EB, create an application, then begin creating an environment.

In the configuration of the environment, go into the Software section and tell it that you're going to use npm run prod to start your server.:

Now, go into the Load Balancers section and, as shown in the pic below:

1. add a listener on port 9000
2. create a process on port 9000 and enable stickiness (I called mine peerjsServer)
3. add Rules for each URL path you want to use to access the server, and have each of those rules assigned to the process you created (peerjsServer). Also point the default to that process, so that health checks on 80 get through successfully to your server

You may need to hop over to the EC2 dashboard in the AWS UI in order to make sure that the necessary Security Groups are defined there. I think I created the first two on the and the last two were default creations, but I don't recall. Anyway, they need to have port 9000 open for inbound and outbound (port 80 is there by default all the time):

Back to the EB configuration, go to the Instances section and make sure that your instance has the Security Groups assigned to it:

I ran react-scripts build to make the /build directory containing the production version of the server UI(this is create-react-apps stuff that I'm not covering here).

In my code, I start the server using a server.js that makes a server that runs both the peerjs-server ws server and an http server.