Considering URL redirections: How to use GUIs of web applications running in different containers within the same docker network on a remote server?

Route all requests through a single container - This is the correct approach.

See API gateway pattern

The best solution that I could find so far. It does not serve for production. However, for prototyping or if simply trying to emulate a server structure by using containers it is an easy setup.

General Idea:Deploy a third VNC container running a Webbrowser and forward the port of this third container to your local machine. As the third container is part of the docker network it can naturally resolve the internal domain names and the VNC installation on your local machine enables you to interact with the GUIs.

Approach

1. Add the VNC to the docker-compose of the original question.
2. Enable X11 forwarding on the server and client-side.
3. Forward the port of the VNC container using ssh.
4. Install VNC on the client, start a new session, and enter the predefined password.
5. Try it out.

Step by Step

1. Add the VNC container (inspired by creack's post on stackoverflow) to the docker-compose file from the original question:

version: "3.4"services:  openam:    image: openidentityplatform/openam    ports:     - 5001:8080    command: /usr/local/tomcat/bin/catalina.sh run  flask:    build: ./SimpleHTTPServer    ports:     - 5002:8000    command: python -m http.server 8000  firefoxVnc:    container_name: firefoxVnc    image: creack/firefox-vnc    ports:     - 5900:5900    environment:     - HOME=/    command: x11vnc -forever -usepw -create

• Run the docker-compose: docker-compose up

2. Enable X11 forwarding on the server and client-side.

• On client side $ vim ~/.ssh/config and add the following lines:

Host * ForwardAgent yes ForwardX11 yes

• On server-side run $ vim /etc/ssh/sshd_config and edit the following lines:

X11Forwarding yes X11DisplayOffset 10

3. Forward the port of the VNC container using ssh

ssh -v -X -L 5900:localhost:5900 gw.example.com

• Make sure to include the -X flag for X11. The -v flag is just for debugging.

4. Install VNC on the client, start a new session and enter the predefined password.

• Install VNC viewer on your local machine
• Open the installed viewer and start a new session using the forwarded address localhost:59000
• When prompted type in the password 1234 which was set in the original Dockerfile of the VNC dicker image (see creack's post linked above).

5. You can now either go to openam:8080/openam/ or apache:80 within the browser of the VNC localhost:5900 session.

An even better solution that is clean, straightforward, and also works perfectly when running parts of the application on different virtual machines.

Setup and Use an SSH SOCKS Tunnel

For Google Chrome and macOS:

• Set your network settings to host within the Dockerfile or docker-compose.
• Start an SSH tunnel:

$ ssh -N -D 9090 [USER]@[SERVER_IP]

• Add the SwitchyOmega proxy addon to your Chrome browser.
• Configure SwitchyOmega by going to New Profile > Proxy Profile, clicking create, entering the same server IP as for the ssh command and the port 9090.
• Open a new terminal tap and run:

"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome" \    --user-data-dir="$HOME/proxy-profile" \    --proxy-server="socks5://localhost:9090"

• A new Crome session will open up in which you can simply browse your docker applications.

Reference | When running Linux or Windows | Using Firefox (no addon needed)

The guide How to Set up SSH SOCKS Tunnel for Private Browsing explains how to set up an SSH SOCKS Tunnel running Mac, Windows, or Linux and using Google Chrome or Firefox. I simply referenced the setup for macOS and Crome in case the link should die.