Building and Promoting a Linux-based Operating System to Support Virtual Organizations for Next Generation Grids Executive Summary

The XtreemOS operating system provides for Grids what a traditional operating system offers for a single computer: abstraction from the hardware and secure resource sharing between different users. It thus simplifies the work of users belonging to virtual organizations by giving them the illusion of using a traditional computer while removing the burden of complex resource management issues of a typical Grid environment. When a user runs an application on XtreemOS, the operating system automatically finds all resources necessary for the execution, configures user’s credentials on the selected resources and starts the application. The XtreemOS operating system provides three major distributed services to users: application execution management (providing scalable resource discovery and job scheduling for distributed interactive applications), data management (accessing and storing data in XtreemFS, a POSIX-like file system spanning the Grid) and virtual organization management (building and operating dynamic virtual organizations). The implementation of this new Grid operating system introduces new challenges: • Scalability: supporting hundreds of thousands of nodes and millions of users dynamically joining and leaving the Grid, • Transparency: hiding the complexity of the Grid by distributed operating system services allowing to run new and legacy applications seamlessly, • Interoperability: complying with all major standards such as POSIX and SAGA, • Dependability: providing reliability and high availability through checkpointing and replication, • Security: ensuring trust and integrity according to customizable policies.