Abstract: 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.
