A Platform for Interactive Software Experiments in Massive Open Online Courses

Massive open online courses enjoy a surge of popularity: Numerous platforms such as Coursera, Udacity, edX and many more offer a variety of high-quality courses to learners worldwide. Hasso Plattner Institute is operating its own platform openHPI where selected courses are available. These platforms are well-suited for the presentation of video and reading material and offer opportunities for interaction in web forums. Assignments, however, are usually limited to simple quizzes or basic question & answer tasks, although, a very important component of teaching are practical assignments that allow students to gather hands-on experiences. With InstantLab, we have created a self-service web platform for interactive software experiments that is used in our curriculum: Experiments are provided as VM images which are executed on our in-house private cloud and accessed over a remote-desktop connection embedded in the web browser - requiring no additional software on the users computers. In this paper, we discuss how interactive software experiments can be added to state-of-the-art MOOCs using the example of openHPI and InstantLab. We propose XCloud - a hybrid cloud architecture that takes into consideration the unique challenges of MOOC scenarios of scaling issues and resource management for anonymous users. It provides the following benefits to MOOC infrastructures: hosting in a private cloud with support for dynamic scale out to public cloud resources in peak load situations; support for live hands-on experiments with single machines and networks of machines; support to access a limited set of machines with special hardware resources (e.g. GPUs, hardware accelerators); and a trust-based access control scheme that can be used to achieve self-managing resource assignment. We report on our practical experiences with InstantLab and outline its transition to the XCloud architecture. This effort bridges the two fields of computer science and education research: Collected data and practical experience from the from our platform can be used to improve the quality of distance learning and its didactic methods.