A key feature of the XtreemOS design is native support for Virtual Organisations.

Virtual Organisations (VOs) are now considered a key aspect of Grids, which allow Grids to scale.  A VO can be seen as a temporary or permanent coalition of geographically dispersed entities (individuals, groups, organizational units or entire organizations) that pool resources, capabilities and information to achieve common objectives. The resources can be physical equipment such as computing or other facilities, or other capabilities such as knowledge, information or data. 

The exact definition of VO differs from project to project.  Some approaches concentrate on the legal or contractual arrangements between the participating entities.  Others take a task-oriented approach, emphasising the workflow required to achieve a goal.  VOs can range from long-lived collaborations with many users, typically found in large-scale scientific applications, to short-lived, dynamic ventures set up to achieve one task between a small number of participants, more typically of commercial scenarios.  A general purpose Grid Operating system should take a flexible approach to accommodate as wide a range of applications as possible; indeed the use cases in XtreemOS reflect this diversity.

Thus the approach in XtreemOS is to define a minimal definition of the features of VOs, and to provide a toolbox which can be configured to the needs of the application.  Key components of a VO are:

• an administrator of the VO;
• a set of users in different domains;
• a set of resources in different domains;
• a set of roles which users and resources can play in the VO;
• a set of policies on resource availability and access control;
• an expiry time of the VO. 

VO Goals or Workflows are not modelled explicitly, though XtreemOS tools should allow these to be supported at the application level. This will typically require enforcement of policies, event notification of the completion of processes, and monitoring of exceptional events, such as jobs still executing at VO expiration.  Similarly, we would not expect kernel support of contractual arrangements, but require monitoring and enforcement of policies which can be derived from contracts.

XtreemOS aims to provide native support for the management of VOs in a secure and scalable way, without compromising on flexibility and performance.

Publications

Project deliverables

WP2.1 - Virtual Organisation Support in Linux

• Linux XOS specification (D2.1.1) - January  2007

• Design and implementation of basic version of node-level VO support mechanisms (D2.1.2) - December 2007

• Design and implementation of basic checkpoint-restart mechanisms in Linux (D2.1.3) - December 2007

• Prototype of the basic version of Linux-XOS (D2.1.4) - December 2007
• Design and Implementation of Advanced Node-level VO Support Mechanisms (D2.1.5) - December 2008

WP3.5 - Security Services in Virtual Organisations

• State of the art in the security for OS and Grids (D3.5.1) - December 2006
• Security requirements for a Grid-based OS (D3.5.2) - January 2007
• First draft specification of XtreemOS security services (D3.5.3) - May 2007
• Second draft specification of XtreemOS security services (D3.5.4) - December 2007)

• First prototype of implementation of security services (D3.5.5) - December 2007
• Report on formal analysis of security properties (D3.5.6) - December 2007
• Security for the XtreemFS File System (D3.5.7) - May 2008
• Specification of application firewall (D3.5.8) - May 2008

Journals and conferences

• XtreemOS: a Grid Operating System Making your Computer Ready for Participating in Virtual Organizations, Christine Morin (invited talk), IEEE International Symposium on Object/component/service-oriented Real-time distributed Computing (ISORC), Santorini Island, Greece, May 2007 (pdf).
• Virtual Organization Management in XtreemOS: an Overview, E. Yang, B. Matthews, A. Lakhani, Y. Jégou, C. Morin, O. Sanchez, C. Franke, P. Robinson, A. Hohl, B. Scheuermann, D. Vladusic, H. Yu, A. Qin, R. Lee, E. Focht, M. Coppola. , CoreGrid Symposium, Rennes, France, August 2007 (pdf).
• Threat analysis and attacks on XtreemOS: A Grid-enabled Operating System, A. D. Lakhani, E. Y. Yang, B. Matthews, I. Johnson, S. Naqvi, G. C. Silaghi, CoreGrid symposium, Rennes, France, August 2007 (pdf).
• XtreemOS: Towards a Grid Operating System with Virtual Organisation Support, I. Johnson, A. Lakhani, B. Matthews, E. Yang, C. Morin, UK eScience All Hands Meeting, September 2007 (pdf).
• A grid operating system providing native virtual organization support, C. Morin, Y. Jégou, A. Lèbre, T. Priol, Ó.D. Sánchez, H. Yu, E. Yang, B. Matthews, L.P. Prieto.  In E-Sciences 2007 conference (poster) , Bangalore, India, December 2007.
• A Formal Security Requirements Model for a Grid-Based Operating System, B. Aziz, A. Arenas, J. Bicarregui, B. Matthews, E. Yang, BCS-FACS Christmas 2007 Meeting: Formal Methods In Industry, London, UK, British Computing Society Electronic Workshops in Computing (eWiC) Series (pdf).
• Virtual organization support within a grid-wide operating system, M.Coppola, Y. Jégou, B. Matthews, C. Morin, L.P. Prieto, Ó.D. Sánchez, E.Y. Yang, H.Yu.  IEEE Internet Computing, 12(2) :20–28, March 2008 (pdf).
• Modelling Security Properties in a Grid-Based Operating System with Anti-Goals, A. Arenas, B. Aziz, J. Bicarregui, B. Matthews, E. Yang,  Proc. Symposium on Requirements Engineering for Information Security (SRIES 2008), Barcelona, Spain, March 2008, IEEE Computer Society (pdf)
• Xtreemos grid checkpointing architecture, J. Mehnert-Spahn, M. Schoettner, D. Margery, C. Morin, J. Corbalan, T. Cortes, In IEEE International Symposium on Cluster Computing and the Grid (CCGRID 2008), poster session, Lyon, France, May 2008 (pdf).
• XOS-SSH: A Lightweight User-Centric Tool to Support Remote Execution in Virtual Organizations, An Qin, Haiyan Yu, Chengchun Shu, Bing Xu, First USENIX workshop on Large-Scale Computing (LASCO’08), Boston (USA), June 2008 (pdf)