Service discovery using Marathoner

Modern distributed applications require a way to communicate with each other, which means that one application should know the presence of the other application when they are on the same network. This is called service discovery. In this section, we will take a look at the service discovery of web services that run on Marathon. One can adopt this approach for most of the stateless applications running on top of Marathon.

We will use the combination of the popular HAProxy TCP/HTTP load balancer along with Marathon's REST API script, which was covered in the previous topics, to regenerate the configuration file of HAProxy for the service discovery of Marathon applications. When a task is spawned on one of the Mesos slaves, they are configured to bind the port to an arbitrary one within the default range of 31,000-32,000.

Service discovery lets the applications running on Marathon communicate with others running alongside Marathon through their configured Marathon...