To benefit from using a loadbalancer we need several machines to distribute the traffic on, evidently.
Thanks to Docker we simply run
docker run -d -p 81:80 testwebsite:1
to get a second machine. This time the container port of the webserver is mapped to port 81. If you now visit <IP OF YOUR VM>:81 you should see your test website.
You can have as many machines as you want to. Simply pay attention to the ports.
Of course we don’t want to write this command manually each time when we want to create a new container. Especially not when we want about 100 new containers. That’s why we wrote a small bash script, which does the job for us.