Software Engineering for Ensembles

Software development is difficult, even if we control most of the operational parameters and if the software is designed to run on a single machine. But in the future we will face an even more challenging task: engineering ensembles consisting of thousands, or even millions, of nodes, all operating in parallel, with open boundaries, possibly unreliable components and network links, and governed by multiple entities. To develop reliable and trustworthy software for these kinds of systems we need to go far beyond the current state of the art and address fundamental problems in software development. We present some challenges and promising avenues for research about software-engineering for ensembles.