Jarek Nabrzyski

Enabling Applications on the Grid: A Gridlab Overview

Grid technology is widely emerging. Still, there is an eminent shortage of real Grid users, mostly due to the lack of a “critical mass” of widely deployed and reliable higher-level Grid services, tailored to application needs. The GridLab project aims to provide fundamentally new capabilities for applications to exploit the power of Grid computing, thus bridging the gap between application needs and existing Grid middleware. We present an overview of GridLab, a large-scale, EU-funded Grid project spanning over a dozen groups in Europe and the US. We first outline our vision of Grid-empowered applications and then discuss GridLab’s general architecture and its Grid Application Toolkit (GAT). We illustrate how applications can be Grid-enabled with the GAT and discuss GridLab’s scheduler as an example of GAT services.

GridLab: a grid application toolkit and testbed

In this paper we present the new project called GridLab which is funded by the European Commission under the Fifth Framework Programme. The GridLab project, made up of computer scientists, astrophysicists and other scientists from various application areas, will develop and implement the grid application toolkit (GAT) together with a set of services to enable easy and efficient use of Grid resources in a real and production grid environment. GAT will provide core, easy to use functionality through a carefully constructed set of generic higher level grid APIs through which an application will be able to call the grid services laying beneath in order to perform efficiently in the Grid environment using various, dramatically wild application scenarios.

Grid scheduling simulations with GSSIM

Grid simulation tools provide frameworks for simulating application scheduling in various grid infrastructures. However, while experimenting with many existing tools, we have encountered two main shortcomings: (i) there are no tools for generating workloads, resources and events ; (ii) it is difficult and time consuming to model different grid levels, i.e. resource brokers, and local level scheduling systems. In this paper we present the grid scheduling simulator (GSSIM), a framework that addresses these shortcomings and provides an easy-to-use Grid scheduling framework for enabling simulations of a wide range of scheduling algorithms in multi-level, heterogeneous grid infrastructures. In order to foster more collaboration in the community at large, GSSIM is complemented with a portal (http://www.gssim.org) that provides a repository of grid scheduling algorithms, synthetic workloads and benchmarks for use with GSSIM.

Dynamic grid scheduling with job migration and rescheduling in the GridLab resource management system

Grid computing has become one of the most important research topics that appeared in the field of computing in the last years. Simultaneously, we have noticed the growing popularity of new Web-based technologies which allow us to create application-oriented Grid middleware services providing capabilities required for dynamic resource and job management, monitoring, security, etc. Consequently, end users are able to get easier access to geographically distributed resources. In this paper we present the results of our experiments with the Grid(Lab) Resource Management System (GRMS), which acts on behalf of end users and controls their computations efficiently using distributed heterogeneous resources. We show how resource matching techniques used within GRMS can be improved by the use of a job migration based rescheduling policy. The main aim of this policy is to shorten job pending times and reduce machine overloads. The influence of this method on application performance and resource utilization is studied in detail and compared with two other simple policies.

A multicriteria approach to two-level hierarchy scheduling in grids

In this paper we address a multicriteria scheduling problem for computational Grid systems. We focus on the two-level hierarchical Grid scheduling problem, in which at the first level (the Grid level) a Grid broker makes scheduling decisions and allocates jobs to Grid nodes. Jobs are then sent to the Grid nodes, where local schedulers generate local schedules for each node accordingly. A general approach is presented taking into account preferences of all the stakeholders of Grid scheduling (end-users, Grid administrators, and local resource providers) and assuming a lack of knowledge about job time characteristics. A single-stakeholder, single-criterion version of the approach has been compared experimentally with the existing approaches.

Multi-Criteria Grid Resource Management Using Performance Prediction Techniques

To date, many of existing Grid resource brokers make their decisions concerning selection of the best resources for computational jobs using basic resource parameters such as, for instance, load. This approach may often be insufficient. Estimations of job start and execution times are needed in order to make more adequate decisions and to provide better quality of service for end-users. Nevertheless, due to heterogeneity of Grids and often incomplete information available the results of performance prediction methods may be very inaccurate. Therefore, estimations of prediction errors should be also taken into consideration during a resource selection phase. We present in this paper the multi-criteria resource selection method based on estimations of job start and execution times, and prediction errors. To this end, we use GRMS [28] and GPRES tools. Tests have been conducted based on workload traces which were recorded from a parallel machine at UPC. These traces cover 3 years of job information as recorded by the LoadLeveler batch management systems. We show that the presented method can considerably improve the efficiency of resource selection decisions.

HPC-Europa: towards uniform access to European HPC infrastructures

One of the goals of the HPC-Europa project is to provide users with a Single Point of Access (SPA) to the resources of HPC centers in Europe. To this end, the HPC-Europa Portal is being built to provide transparent, uniform, flexible and intuitive user access to HPC-Europa resources. In this paper, we present a mechanism that enables end-users to transparently access the diverse services available in the HPC-Europa environment. The uniform job submission interface that uses this mechanism, utilizing the job specification description language (JSDL), is described. We also present the architecture of the SPA, based on the GridSphere portal framework. Finally, we discuss the various interoperability problems encountered, in particular those concerning job submission, security and accounting.

Context Sensitive Mobile Access to Grid Environments and VO Workspaces

This paper examines the problem of giving mobile users a possibility to access interoperability services based on ontologies and predefined concepts providing various meaningful objects and mechanisms to search, discover, invoke, compose and monitor appropriate grid-based services, applications as well as data sources in the Virtual Organization (VO) from any place in the world using mobile devices. Since mobiles as end devices are naturally used by humans to see a ’human-readable’ content, in our opinion, they should also allow them to specify ’human-readable’ queries instead of direct computer-interpretable queries to unknown remote service providers or databases. Based on the knowledge located in the interoperability space user’s requests from mobile devices can be mapped and forwarded automatically to appropriate remote interfaces to take advantages of various functionalities offered by the grid and service providers available today in the Internet. Therefore, more efficient interaction between the user and remote service provider(s) can be established. In our approach, the real ontology services are available from mobile devices via the gateway due to weaknesses of mobile devices and the complexity of the ontology layer within the grid infrastructure. In this paper we describe several grid-based services developed for mobile users as well as some core services which have been adopted to work with mobile devices. Roles of a mobile client, grid-services and gateway played in some novel scenarios of ontology usage are also described. Finally, in this paper we discuss issues related to obstacles and limitations that we have been facing while using the chosen J2ME technology, and the ways we are solving them.

Grid Multicriteria Job Scheduling with Resource Reservation and Prediction Mechanisms

Grids link together computers, data, sensors, large scale scientific instruments, visualization systems, networks and people. They can provide very large pools of computer resources, enable distributed collaborations and deliver increased efficiency and on-demand computing capabilities. The complexity of Grids on one hand and the requirements towards performance and capability on the other hand call for efficient resource management and scheduling mechanisms. Such mechanisms must take into account not only the hardware and software resources, user jobs and applications, but also policies of the resource owners. Policies usually describe cost models for the resource usage, security mechanisms, quality of service of resource provisioning etc. The problem of scheduling jobs in real Grid environments is very difficult. Due to lack of time characteristics of jobs, and difficulties in characterizing the overall system, traditional OR techniques usually fail or achieve very weak results. Usually, best effort scheduling is the best option. There are, however, some ways to deal with the problems described above.

Security and performance enhancements to OGSA-DAI for Grid data virtualization

In this paper we describe our work on enabling dynamic access control and secure management over federated data resources, such as relational or XML databases exposed to public network infrastructures via OGSA‐DAI middleware. We have proposed some extensions to the OGSA‐DAI architecture and successfully implemented new mechanisms enabling secure communication and distributed data integrity along with fine‐grain authorization and policy enforcement to minimize the complexity of the security right management. As a proof of concept some preliminary results of various performance tests of our solutions are also presented in this paper. We then analyze our achievements and describe future work and research. Copyright