Péter Kacsuk

WS-PGRADE/gUSE Generic DCI Gateway Framework for a Large Variety of User Communities

The WS-PGRADE/gUSE generic DCI gateway framework has been developed to support a large variety of user communities. It provides a generic purpose, workflow-oriented graphical user interface to create and run workflows on various DCIs including clusters, Grids, desktop Grids and clouds. The framework can be used by NGIs to support small user communities who cannot afford to develop their own customized science gateway. The WS-PGRADE/gUSE framework also provides two API interfaces (Application Specific Module API and Remote API) to create application-specific science gateways according to the needs of different user communities. The paper describes in detail the workflow concept of WS-PGRADE, the DCI Bridge service that enables access to most of the popular European DCIs and the Application Specific Module and Remote API concepts to generate application-specific science gateways.

Multi-Grid, multi-user workflows in the P-GRADE Grid portal

Computational Grids connect resources and users in a complex way in order to deliver nontrivial qualities of services. According to the current trend various communities build their own Grids and due to the lack of generally accepted standards these Grids are usually not interoperable. As a result, large scale sharing of resources is prevented by the isolation of Grid systems. Similarly, people are isolated, because the collaborative work of Grid users is not supported by current environments. Each user accesses Grids as an individual person without having the possibility of organizing teams that could overcome the difficulties of application development and execution more easily. The paper describes a new workflow-oriented portal concept that solves both problems. It enables the interoperability of various Grids during the execution of workflow applications, and supports users to develop and run their Grid workflows in a collaborative way. The paper also introduces a classification model that can be used to identify workflow-oriented Grid portals based on two general features: Ability to access multiple Grids, and support for collaborative problem solving. Using the approach the different potential portal types are introduced, their unique features are discussed and the portals and Problem Solving Environments (PSE) of our days are classified. The P-GRADE Portal as a Globus-based implementation for the classification model is also presented.

GEMLCA: Running Legacy Code Applications as Grid Services

There are many legacy code applications that cannot be run in a Grid environment without significant modification. To avoid re-engineering of legacy code, we developed the Grid Execution Management for Legacy Code Architecture (GEMLCA) that enables deployment of legacy code applications as Grid services. GEMLCA implements a general architecture for deploying legacy applications as Grid services without the need for code re-engineering, or even access to the source files. With GEMLCA, only a user-level understanding is required to run a legacy application from a standard Grid service client. The legacy code runs in its native environment using the GEMLCA resource layer to communicate with the Grid client, thus hiding the legacy nature of the application and presenting it as a Grid service. GEMLCA as a Grid service layer supports submitting jobs, getting their results and status back. The paper introduces the GEMLCA concept, its life cycle, design and implementation. It also presents as an example a legacy simulation code that has been successfully transformed into a Grid service using GEMLCA.

P-GRADE portal family for grid infrastructures

P‐GRADE portal is one of the most widely used general‐purpose grid portal in Europe. The paper summarizes the most advanced features of P‐GRADE, such as parameter sweep workflow execution, multi‐grid workflow execution and integration with the DSpace workflow repository. It also shows the NGS P‐GRADE portal that extends P‐GRADE with the GEMLCA legacy code execution support in Grid systems, as well as with coarse‐grain workflow interoperability services. Next, the paper introduces the second generation P‐GRADE portal called WS‐PGRADE that merges the advanced features of the first generation P‐GRADE portals and extends them with new workflow and architecture concepts. Finally, the application‐specific science gateway of the CancerGrid project is briefly described to demonstrate that application‐specific portals can easily be developed on top of the general‐purpose WS‐PGRADE portal. Copyright

P-GRADE: a grid programming environment

P-GRADE provides a high-level graphical environment to develop parallel applications transparently both for parallel systems and the Grid. P-GRADE supports the interactive execution of parallel programs as well as the creation of a Condor, Condor-G or Globus job to execute parallel programs in the Grid. In P-GRADE, the user can generate either PVM or MPI code according to the underlying Grid where the parallel application should be executed. PVM applications generated by P-GRADE can migrate between different Grid sites and as a result P-GRADE guarantees reliable, fault-tolerant parallel program execution in the Grid. The GRM/PROVE performance monitoring and visualisation toolset has been extended towards the Grid and connected to a general Grid monitor (Mercury) developed in the EU GridLab project. Using the Mercury/GRM/PROVE Grid application monitoring infrastructure any parallel application launched by P-GRADE can be remotely monitored and analysed at run time even if the application migrates among Grid sites. P-GRADE supports workflow definition and co-ordinated multi-job execution for the Grid. Such workflow management can provide parallel execution at both inter-job and intra-job level. Automatic checkpoint mechanism for parallel programs supports the migration of parallel jobs inside the workflow providing a fault-tolerant workflow execution mechanism. The paper describes all of these features of P-GRADE and their implementation concepts.

A graphical development and debugging environment for parallel programs

Abstract To provide high-level graphical support for PVM (Parallel Virtual Machine) based program development, a complex programming environment (GRADE) is being developed. GRADE currently provides tools to construct, execute, debug, monitor and visualize message-passing parallel programs. It offers a high-level graphical programming abstraction mechanism to construct parallel applications by introducing a new graphical language called GRAPNEL. GRADE also provides the programmer with the same graphical user interface during the program design and debugging stages. A distributed debugging engine (DDBG) assists the user in debugging GRAPNEL programs on distributed memory computer architectures. Tape/PVM and PROVE support the performance monitoring and visualization of parallel programs developed in the GRADE environment.

Solving the grid interoperability problem by P-GRADE portal at workflow level

Grid interoperability has recently become a major issue at Grid forums. Most of the current ideas try to solve the problem at the middleware level where unfortunately too many components (information system, broker, etc.) should be made interoperable. As an alternative concept the P-GRADE portal is the first Grid portal that tries to solve the problem at the level of workflows. It means that the components of a workflow can be executed simultaneously in several Grids. In this way the user can exploit more parallelism than inside one Grid. More than that the workflow level completely hides the low level Grid details for the end-user who does not have to learn the low level Grid commands of different Grids. In this way porting workflow application between different Grids can be done with minimal user efforts. The paper describes those features and techniques that are provided and used by the P-GRADE portal to solve the Grid interoperability problem.

EDGeS: Bridging EGEE to BOINC and XtremWeb

Desktop Grids, such as XtremWeb and BOINC, and Service Grids, such as EGEE, are two different approaches for science communities to gather computing power from a large number of computing resources. Nevertheless, little work has been done to combine these two Grid technologies in order to establish a seamless and vast Grid resource pool. In this paper we present the EGEE Service Grid, the BOINC and XtremWeb Desktop Grids. Then, we present the EDGeS solution to bridge the EGEE Service Grid with the BOINC and XtremWeb Desktop Grids.

High-level grid application environment to use legacy codes as OGSA grid services

One of the biggest obstacles in the wide-spread industrial take-up of grid technology is the existence of a large amount of legacy code that is not accessible as grid services. The paper describes a new approach (GEMLCA: grid execution management for legacy code architecture) to deploy legacy codes as grid services without modifying the original code. Moreover, we show a workflow execution oriented grid portal technology (P-GRADE portal) by which such legacy code based grid services can be applied in complex business processes. GEMLCA has been implemented as GT-3 services but can be easily ported into the new WSRF grid standards.

Workflow Support for Complex Grid Applications: Integrated and Portal Solutions

In this paper we present a workflow solution to support graphically the design, execution, monitoring, and performance visualisation of complex grid applications. The described workflow concept can provide interoperability among different types of legacy applications on heterogeneous computational platforms, such as Condor or Globus based grids. The major design and implementation issues concerning the integration of Condor tools, Mercury grid monitoring infrastructure, PROVE performance visualisation tool, and the new workflow layer of P-GRADE are discussed in two scenarios. The integrated version of P-GRADE represents the thick client concept, while the portal version needs only a thin client and can be accessed by a standard web browser. To illustrate the application of our approach in the grid, an ultra-short range weather prediction system is presented that can be executed in a grid testbed and visualised not only at workflow level but at the level of individual parallel jobs, too.