Checkpointing Orchestrated Web Services

Web Services are built on service-oriented architecture which is based on the notion of building applications by discovering and orchestrating services available on the web. Complex business processes can be realized by discovering and orchestrating already available services on the web. In order to make these orchestrated web services resilient to faults; we proposed a simple and elegant checkpointing policy called Call based Global Checkpointing of Orchestrated web services which specifies that when a web service calls another web service the calling web service has to save its state. But performance of the web services implementing this policy reduces due to checkpointing overhead. In an effort to improvise this policy, we propose in this paper, a checkpointing policy which uses Predicted Execution Time and Mean Time Between Failures of the called web services to make checkpointing decisions. This policy aims at reducing the required number of Call based Checkpoints but at the same time maintains the resilience of web services to faults

Structured and flexible gray-box composition using invasive distributed patterns

ISBN = {ISSN: 1646-3692}International audienceThe evolution of complex distributed software systems often requires intricate composition operations in order to adapt or add functionalities, to react to unanticipated changes, or to apply performance improvements that cannot be modularized in terms of existing services and components. These evolutions often need controlled access to selected parts of the implementation, e.g., to manage exceptional situations and crosscutting within services and their compositions. However, existing composition techniques typically support only interface-level (black-box) composition or arbitrary access to the implementation (gray-box or white-box composition). In this paper, we present a structured approach to the composition of complex software systems that require invasive modifications. Concretely, we provide three contributions: (i) we present a small kernel composition language for structured gray-box composition using invasive distributed patterns; (ii) we motivate that gray-box composition approaches should be defined and evaluated in terms of the flexibility and control they provide, a notion of degrees of invasiveness is introduced to help assess this trade-off; (iii) we apply our approach to a new case study of evolution and evaluate it in the context of two previous studies involving two real-world software systems: benchmarking of grid algorithms with NASGrid and transactional replication with JBoss Cache. As a main result, we show that gray-box composition using invasive distributed patterns allows the declarative and modular definition of evolutions of real-world applications that need moderate to high degrees of invasive modifications

Autonomic Approach based on Semantics and Checkpointing for IoT System Management

Le résumé en français n'a pas été communiqué par l'auteur.Le résumé en anglais n'a pas été communiqué par l'auteur

A Dynamic Workflow Simulation Platform

International audienceAbstract--In numeric optimization algorithms errors at application level considerably affect the performance of their execution on distributed infrastructures. Hours of execution can be lost only due to bad parameter configurations. Though current grid workflow systems have facilitated the deployment of complex scientific applications on distributed environments, the error handling mechanisms remain mostly those provided by the middleware. In this paper, we propose a collaborative platform for the execution of scientific experiments in which we integrate a new approach for treating application errors, using the dynamicity and exception handling mechanisms of the YAWL workflow management system. Thus, application errors are correctly detected and appropriate handling procedures are triggered in order to save as much as possible of the work already executed

The role of the RM-ODP computational viewpoint concepts in the MDA approach

An MDA design approach should be able to accommodate designs at different levels of platform-independence. We have proposed a design approach previously (in [2]), which allows these levels to be identified. An important feature of this approach is the notion of abstract platform. An abstract platform is determined by the platform characteristics that are relevant for applications at a certain level of platform-independence, and must be established by considering various design goals. In this paper, we define a framework that makes it possible to use RM-ODP concepts in our MDA design approach. This framework allows a recursive application of the computational viewpoint at different levels of platform-independence. This is obtained by equating the RM-ODP notion of infrastructure to our notion of abstract platform

Using an Actor Framework for Scientific Computing: Opportunities and Challenges

We examine the challenges and advantages of using an actor framework for programming and execution of scientific workflows. The following specific topics are studied: implementing workflow semantics and typical workflow patterns in the actor model, parallel and distributed execution of workflow activities using actors, leveraging event sourcing as a novel approach for workflow state persistence and recovery, and applying supervision as a fault tolerance model for workflows. In order to practically validate our research, we have created Scaflow, an Akka-based programming library and workflow execution engine. We study an example workflow implemented in Scaflow, and present experimental measurements of workflow persistence overhead