Mine Altunay

A Science Driven Production Cyberinfrastructure--the Open Science Grid

This article describes the Open Science Grid, a large distributed computational infrastructure in the United States which supports many different high-throughput scientific applications, and partners (federates) with other infrastructures nationally and internationally to form multi-domain integrated distributed systems for science. The Open Science Grid consortium not only provides services and software to an increasingly diverse set of scientific communities, but also fosters a collaborative team of practitioners and researchers who use, support and advance the state of the art in large-scale distributed computing. The scale of the infrastructure can be expressed by the daily throughput of around seven hundred thousand jobs, just under a million hours of computing, a million file transfers, and half a petabyte of data movement. In this paper we introduce and reflect on some of the OSG capabilities, usage and activities.

Definition and Implementation of a SAML-XACML Profile for Authorization Interoperability Across Grid Middleware in OSG and EGEE

In order to ensure interoperability between middleware and authorization infrastructures used in the Open Science Grid (OSG) and the Enabling Grids for E-science (EGEE) projects, an Authorization Interoperability activity was initiated in 2006. The interoperability goal was met in two phases: firstly, agreeing on a common authorization query interface and protocol with an associated profile that ensures standardized use of attributes and obligations; and secondly implementing, testing, and deploying on OSG and EGEE, middleware that supports the interoperability protocol and profile. The activity has involved people from OSG, EGEE, the Globus Toolkit project, and the Condor project. This paper presents a summary of the agreed-upon protocol, profile and the software components involved.

Optimal response to attacks on the open science grid

Cybersecurity is a growing concern, especially in open grids, where attack propagation is easy because of prevalent collaborations among thousands of users and hundreds of institutions. The collaboration rules that typically govern large science experiments as well as social networks of scientists span across the institutional security boundaries. A common concern is that the increased openness may allow malicious attackers to spread more readily around the grid. We consider how to optimally respond to attacks in open grid environments. To show how and why attacks spread more readily around the grid, we first discuss how collaborations manifest themselves in the grids and form the collaboration network graph, and how this collaboration network graph affects the security threat levels of grid participants. We present two mixed-integer program (MIP) models to find the optimal response to attacks in open grid environments, and also calculate the threat level associated with each grid participant. Given an attack scenario, our optimal response model aims to minimize the threat levels at unaffected participants while maximizing the uninterrupted scientific production (continuing collaborations). By adopting some of the collaboration rules (e.g., suspending a collaboration or shutting down a site), the model finds optimal response to subvert an attack scenario.

New science on the Open Science Grid

The Open Science Grid (OSG) includes work to enable new science, new scientists, and new modalities in support of computationally based research. There are frequently significant sociological and organizational changes required in transformation from the existing to the new. OSG leverages its deliverables to the large-scale physics experiment member communities to benefit new communities at all scales through activities in education, engagement, and the distributed facility. This paper gives both a brief general description and specific examples of new science enabled on the OSG. More information is available at the OSG web site: www.opensciencegrid.org.

Bringing Federated Identity to Grid Computing

The Fermi National Accelerator Laboratory (FNAL) is facing the challenge of providing scientific data access and grid submission to scientific collaborations that span the globe but are hosted at FNAL. Researchers in these collaborations are currently required to register as FNAL users and obtain FNAL credentials to access grid resources to perform their scientific computations. These requirements burden researchers with managing additional authentication credentials, and put additional load on FNAL for managing user identities. Our design integrates the existing InCommon federated identity infrastructure, CILogon Basic CA, and MyProxy with the FNAL grid submission system to provide secure access for users from diverse experiments and collaborations without requiring each user to have authentication credentials from FNAL. The design automates the handling of certificates, so users do not need to manage them manually. Although the initial implementation is for FNALs grid submission system, the design and the core of the implementation are general and could be applied to other distributed computing systems.