Nikos Parlavantzas

The Role of Overlay Services In a Self-Managing Framework for Dynamic Virtual Organizations

We combine and extend recent results in autonomic computing and structured peer-to-peer to build an infrastructure for constructing and managing dynamic virtual organizations. The paper focuses on the middle layer of the proposed infrastructure, in-between the Niche overlay system on the bottom, and an architecturebased management system based on Jade on the top. The middle layer, the overlay services, are responsible for all sensing and actuation carried out by the VO management. We describe in detail the API of the resource and component overlay services both on the management node and the nodes hosting resources. We present a simple use case demonstrating resource discovery, initial deployment, self-configuration as a result of resource availability change, self-healing, self-tuning and self-protection. The advantages of the design are 1) the overlay services are in themselves self-managing, and sensor/actuation services they provide are robust, 2) management can be dealt with declaratively and at a high-level, and 3) the overlay services provide good scalability in dynamic VOs.

Enabling Self-Management Of Component Based Distributed Applications

Deploying and managing distributed applications in dynamic Grid environments requires a high degree of autonomous management. Programming autonomous management in turn requires programming environm ...

Towards Automatic Creation of Web Services for Grid Component Composition

While high-level software components simplify the programming of grid applications and Web services increase their interoperability, developing such components and configuring the interconnecting services is a demanding task. In this paper, we consider the combination of Higher-Order Components (HOCs) with the Fractal component model and the ProActive library.

An economic approach for application qos management in clouds

Virtualization provides increased control and flexibility in how resources are allocated to applications. However, common resource provisioning mechanisms do not fully use these advantages; either they provide limited support for applications demanding quality of service, or the resource allocation complexity is high. To address this problem we propose a novel resource management architecture for virtualized infrastructures based on a virtual economy. By limiting the coupling between the applications and the resource management, this architecture can support diverse types of applications and performance goals while ensuring an efficient resource usage. We validate its use through simple policies that scale the resource allocations of the applications vertically and horizontally to meet application performance goals.

Performance and Scalability of a Component-Based Grid Application

Component-based development has emerged as an effective approach to building flexible systems, but there is little experience in applying this approach to grid programming. This paper presents our experience with reengineering a high performance numerical solver to become a component-based grid application. The adopted component model is an extension of the generic fractal model that specifically targets grid environments. The paper provides qualitative and quantitative evidence that componentisation has improved the modifiability and reusability of the application while not significantly affecting performance.

On the use of a proportional-share market for application SLO support in clouds

Virtualization provides increased control and flexibility on how resources are allocated to applications. However, common resource provisioning mechanisms do not fully use these advantages; either they provide limited support for applications demanding quality of service, or the resource allocation complexity is high. To address these issues we developed Themis, a market-based application management platform. By limiting the coupling between the applications and resource management, Themis can support diverse types of applications and performance goals while ensuring maximized resource usage. In this paper we present the performance of Themis when users execute batch applications with different Service Level Objectives such as deadlines.

Design support for componentising and grid-enabling scientific applications

Applying component-based development requires design support in the form of methods, frameworks, and tools. To this end, this paper first proposes a componentisation approach and then applies this approach to re-engineer a numerical application into a component-based application. The paper provides qualitative and quantitative evidence that componentisation has improved the modifiability and reusability of the application without significantly affecting performance.

Resource Management in Cloud Platform as a Service Systems: Analysis and Opportunities

Platform-as-a-Service (PaaS) clouds offer services to automate the deployment and management of applications, relieving application owners of the complexity of managing the underlying infrastructure resources. However, application owners have an increasingly larger diversity and volume of workloads, which they want to execute at minimum cost while maintaining desired performance guarantees. In this paper we investigate how existing PaaS systems cope with this challenge. In particular, we first present a taxonomy of commonly-encountered design decisions regarding how PaaS systems manage underlying resources. We then use this taxonomy to analyze an extensive set of PaaS systems targeting different application domains. Based on this analysis, we identify several future research opportunities in the PaaS design space, which will enable PaaS owners to reduce hosting costs while coping with the workload variety.

Tools for Architecture Based Autonomic Systems

autonomic computing, an approach to providing systems with self managing properties. Autonomic computing aims to address the increasing complexity of the administration of large systems. The contribution of this paper is to provide a generic tool to ease the development of autonomic managers. Using this tool, an administrator provides a set of alternative architectures and specifies conditions that are used by autonomic managers to update architectures at runtime. Software changes are computed as architectural differences in terms of component model artifacts (components, attributes, bindings, etc.). These differences are then used to migrate into the next architecture by reconfiguring only the required part of the running system.

Distributed Control Loop Patterns for Managing Distributed Applications

In this paper we discuss various control loop patterns for managing distributed applications with multiple control loops. We introduce a high-level framework, called DCMS, for developing, deploying and managing component-based distributed applications in dynamic environments. The control loops, and interactions among them, are illustrated in the context of a distributed self-managing storage service implemented using DCMS to achieve various self-* properties. Different control loops are used for different self-* behaviours, which illustrates one way to divide application management, which makes for both ease of development and for better scalability and robustness when managers are distributed. As the multiple control loops are not completely independent, we demonstrate different patterns to deal with the interaction and potential conflict between multiple managers.