Raül Sirvent

Programming Grid Applications with GRID Superscalar

The aim of GRID superscalar is to reduce the development complexity of Grid applications to the minimum, in such a way that writing an application for a computational Grid may be as easy as writing a sequential application. Our assumption is that Grid applications would be in a lot of cases composed of tasks, most of them repetitive. The granularity of these tasks will be of the level of simulations or programs, and the data objects will be files. GRID superscalar allows application developers to write their application in a sequential fashion. The requirements to run that sequential application in a computational Grid are the specification of the interface of the tasks that should be run in the Grid, and, at some points, calls to the GRID superscalar interface functions and link with the run-time library.GRID superscalar provides an underlying run-time that is able to detect the inherent parallelism of the sequential application and performs concurrent task submission. In addition to a data-dependence analysis based on those input/output task parameters which are files, techniques such as file renaming and file locality are applied to increase the application performance. This paper presents the current GRID superscalar prototype based on Globus Toolkit 2.x, together with examples and performance evaluation of some benchmarks.

ServiceSs: An Interoperable Programming Framework for the Cloud

The rise of virtualized and distributed infrastructures has led to new challenges to accomplish the effective use of compute resources through the design and orchestration of distributed applications. As legacy, monolithic applications are replaced with service-oriented applications, questions arise about the steps to be taken in order to maximize the usefulness of the infrastructures and to provide users with tools for the development and execution of distributed applications. One of the issues to be solved is the existence of multiple cloud solutions that are not interoperable, which forces the user to be locked to a specific provider or to continuously adapt applications. With the objective of simplifying the programmers challenges, ServiceSs provides a straightforward programming model and an execution framework that helps on abstracting applications from the actual execution environment. This paper presents how ServiceSs transparently interoperates with multiple providers implementing the appropriate interfaces to execute scientific applications on federated clouds.

Automatic Grid workflow based on imperative programming languages

GRID superscalar is a Grid programming environment that enables one to parallelize the execution of sequential applications in computational Grids. The run‐time library automatically builds a task data‐dependence graph of the application and it can be seen as an implicit workflow system. The current interface supports C/C++ and Perl applications. The run‐time library is based on Globus Toolkit 2.x using GRAM and GSIFTP services. In this document we describe the GRID superscalar basics emphasizing those aspects related to Grid workflow, in particular the flexibility of using an imperative language to describe the application. Copyright

A Cloud-unaware Programming Model for Easy Development of Composite Services

Cloud computing is inherently service-oriented: cloud applications are delivered to consumers as services via the Internet. Therefore, these applications can potentially benefit from the Service-Oriented Architecture (SOA) principles: they can be programmed as added-value services composed by pre-existing ones, thus favouring code reuse. However, new programming models are required to simplify their development, along with systems that are capable of orchestrating the execution of the resulting SaaS in the Cloud. In that regard, this paper presents Service Super scalar (Servicess), an alternative to existing PaaS which provides a programming model and execution runtime to ease the development and execution of service-based applications in clouds. Servicess is a task-based model: the user is only required to select the tasks, which can be services or regular methods, to be spawned asynchronously. The application, a composite service, is programmed in a totally sequential way and no API call must be included in the code. The runtime is in charge of automatically orchestrating the execution of the tasks in the Cloud, as well as of elastically deploying new virtual resources depending on the load. After describing the main characteristics of the programming model and the runtime, we evaluate the productivity of Servicess and show how it offers a good trade-off between programmability and runtime performance.

A Service for Reliable Execution of Grid Applications

In grid environments, with the large number of components (both hardware and software) that are involved in application execution, the overall probability that at least one of these components is (temporarily) non-functional is increasing rapidly. In traditional operating systems, such failures are flagged as fatal and the application will be stopped, relying on a re-start after the problem will have been fixed. In a large grid system, this is not a feasible approach as failures happen too frequently while error diagnostics might not be possible at all.

A Rule-based Approach for Infrastructure Providers' Interoperability

Cloud Computing is a new computing paradigm where a large amount of computing capacity is offered on demand and only paying for what you use. Several Infrastructure Providers have adopted this approach offering resources which are easily managed by means of web-based APIs. However, if a user wants to use different providers, the resource management becomes tedious because providers define different API requiring a special implementation for interacting with each of them. In this paper, we present a methodology for making the provider interoperability easier. In this methodology, each providers API is modeled by an ontology. Equivalences between these ontologies are modeled by rules, and messages used in a providers API are converted in calls to another providers API applying these rules. With our approach, users interact with Infrastructure Providers using their most familiar API and the translation to the other APIs is automatically done by the system.

Integration of GRID Superscalar and GridWay Metascheduler with the DRMAA OGF Standard

This paper shares the experiences with one of the BEinGRID pilots, BE14, from a technological point of view. The experiment has integrated GRID superscalar (as programming model) with GridWay (as metascheduler) through the DRMAA standard. Additionally, a portal based in GridSphere has been developed. The portal enables the management of the grid and the automatic deployment and monitoring of applications. This environment has been successfully used to speed up an application that enables new processes and products development in the Chemistry sector with considerable success.

Monitoring and steering Grid applications with GRID superscalar

We present the design and implementation of a general task monitoring and steering system for Grid applications (GSTAT). The system is integrated in the GRID superscalar (GRIDSs) programming framework. Information at the application, Grid node, and individual task levels are supplied upon request. Using the steering capabilities, individual tasks or the whole application can be cancelled. The corresponding jobs can be restarted using fault tolerance and checkpointing capabilities based on GRIDSs. In addition, the computational resources assigned to an application can be modified. GSTAT is tested using high throughput and high performance computing cases on an Internet-based Grid of computers.

Implementing phylogenetic inference with GRID superscalar

The grid has appeared recently as a new computing paradigm. However, to make the use of the grid available to the scientific community, frameworks that enable to easily write applications and to run them efficiently in the grid should be provided. GRID superscalar has been specially designed to satisfy the two requirements mentioned above. This paper presents an implementation of a biological application, fastDNAml, using GRID superscalar. The objective is not only to demonstrate the performance that can be achieved, but the programmability of the framework. The description contains details of the fastDNAml implementation, new features of GRID superscalar and summary of results obtained.

Energy-Aware Programming Model for Distributed Infrastructures

Day after day, cloud technologies are more and more adopted by very diverse types of stakeholders, and this success creates a side-effect problem: the energy spent by this kind of infrastructures is growing bigger every day. With the objective of reducing energy consumption when programming applications for cloud infrastructures, we have implemented energy-aware mechanisms in the COMPSs Programming Model, inside the context of the ASCETiC Project. In this paper, we demonstrate that application-level scheduling can have a big impact on the energy consumed by an application when executed in a heterogeneous cloud. We have implemented an energy-aware scheduling mechanism in COMPSs, together with a versioning technique, and we have run experiments with a use case coming from the real estate sector that proves our hypotheses.