S. Koranda

GriPhyN and LIGO, building a virtual data Grid for gravitational wave scientists

Many Physics experiments today generate large volumes of data. That data is then processed in a variety of ways in order to achieve the understanding of fundamental physical phenomena. The goal of the NSF-funded GriPhyN project (Grid Physics Network) is to enable scientists to seamlessly access data whether it is raw experimental data or a data product which is a result of further processing. GriPhyN provides a new degree of transparency in how data-handling and processing capabilities are integrated to deliver data products to end-users or applications, so that requests for such products are easily mapped into computation and/or data access at multiple locations. GriPhyN refers to the set of all data products available to the user as virtual data. Among the physics applications participating in the project is the Laser Interferometer Gravitational-wave Observatory (LIGO), which is being built to observe the gravitational waves predicted by general relativity. We describe our initial design and prototype of a virtual data Grid for LIGO.

Wide area data replication for scientific collaborations

Scientific applications require sophisticated data management capabilities. We present the design and implementation of a data replication service (DRS), one of a planned set of higher-level data management services for Grids. The capabilities of the DRS are based on the publication capability of the lightweight data replicator (LDR) system developed for the LIGO Scientific Collaboration. We describe LIGO publication requirements and LDR functionality. We also describe the design and implementation of the DRS in the Globus Toolkit Version 4.0 environment and present performance results.

The Pegasus portal: web based grid computing

Pegasus is a planning framework for mapping abstract workflows for execution on the Grid. This paper presents the implementation of a web-based portal for submitting workflows to the Grid using Pegasus. The portal also includes components for generating abstract workflows based on a metadata description of the desired data products and application-specific services. We describe our experiences in using this portal for two Grid applications. A major contribution of our work is in introducing several components that can be useful for Grid portals and hence should be included in Grid portal development toolkits.

Authentication and Authorization Considerations for a Multi-tenant Service

Distributed cyberinfrastructure requires users (and machines) to perform some sort of authentication and authorization (together simply known as \emph{auth}). In the early days of computing, authentication was performed with just a username and password combination, and this is still prevalent today. But during the past several years, we have seen an evolution of approaches and protocols for auth: Kerberos, SSH keys, X.509, OpenID, API keys, OAuth, and more. Not surprisingly, there are trade-offs, both technical and social, for each approach. The NSF Science Gateway communities have had to deal with a variety of auth issues. However, most of the early gateways were rather restrictive in their model of access and development. The practice of using community credentials (certificates), a well-intentioned idea to alleviate restrictive access, still posed a barrier to researchers and challenges for security and auditing. And while the web portal-based gateway clients offered users easy access from a browser, both the interface and the back-end functionality were constrained in the flexibility and extensibility they could provide. Designing a well-defined application programming interface (API) to fine-grained, generic gateway services (on secure, hosted cyberinfrastructure), together with an auth approach that has a lower barrier to entry, will hopefully present a more welcoming environment for both users and developers. This paper provides a review and some thoughts on these topics, with a focus on the role of auth between a Science Gateway and a service provider.

Applications of Virtual Data in the LIGO Experiment

Many Physics experiments today generate large volumes of data. That data is then processed in many ways in order to achieve the understanding of fundamental physical phenomena. Virtual Data is a concept that unifies the view of the data whether it is raw or derived. It provides a new degree of transparency in how data-handling and processing capabilities are integrated to deliver data products to end-users or applications, so that requests for such products are easily mapped into computation and/or data access at multiple locations. GriPhyN (Grid Physics Network) is a NSF-funded project, which aims to realize the concepts of Virtual Data. Among the physics applications participating in the project is the Laser Interferometer Gravitational-wave Observatory (LIGO), which is being built to observe the gravitational waves predicted by general relativity. LIGO will produce large amounts of data, which are expected to reach hundreds of petabytes over the next decade. Large communities of scientists, distributed around the world, need to access parts of these datasets and perform efficient analysis on them. It is expected that the raw and processed data will be distributed among various national centers, university computing centers, and individual workstations. In this paper we describe some of the challenges associated with building Virtual Data Grids for experiments such as LIGO.

Enabling efficient electronic collaboration between LIGO and other astronomy communities using federated identity and COmanage

Identity federations throughout the world including InCommon in the United States, SURFnet in the Netherlands, DFN-AAI in Germany, GakuNin in Japan, and the UK Access Management Federation for Education and Research have made federated identities available for a large number of astronomers, astrophysicists, and other researchers. The LIGO project has recently joined the InCommon federation and is beginning the process to both consume federated identities from outside of LIGO and to make the LIGO identities issued to collaboration members available for consumption by other research communities. Consuming federated identity, however, is only the beginning. Realizing the promise of multi-messenger astronomy requires efficient collaboration among individuals from multiple communities. Efficient collaboration begins with federated identity but also requires robust collaboration management platforms providing consistent, scalable identity and access control information to collaboration applications including wikis, calendars, mailing lists and science portals. LIGO, together with collaborators from Internet2, is building the COmanage suite of tools for Collaborative Organization Management. Using COmanage and leveraging federated identities we plan to streamline electronic collaboration between LIGO and other astronomy projects so that scientists spend less time managing accounts and access control and more time doing science.