Virtual machines & volunteer computing: Experience from LHC@Home: Test4Theory project

Volunteer desktop grids are nowadays becoming more and more powerful thanks to improved high end components: multi-core CPUs, larger RAM memories and hard disks, better network connectivity and bandwidth, etc. As a result, desktop grid systems can run more complex experiments or simulations, but some problems remain: The heterogeneity of hardware architectures and software (library dependencies, code length, big repositories, etc.) make it very difficult for researchers and developers to deploy and maintain a software stack for all the available platforms. In this paper, the employment of virtualization is shown to be the key to solve these problems. It provides a homogeneous layer allowing researchers to focus their efforts on running their experiments. Inside virtual custom execution environments, researchers can control and deploy very complex experiments or simulations running on heterogeneous grids of high-end computers. The following work presents the latest results from CERN's LHC@home Test4Theory project, the first BOINC project using virtualization technology, where all the simulations are run inside virtual machines on a wide variety of volunteers' platforms.