Philippe Merle

A Component-based Software Infrastructure for Ubiquitous Computing

Multiplication of mobile devices and generalized use of wireless networks imply changes on the design and execution of distributed software applications targeting ubiquitous computing. Many strong requirements have to be addressed: heterogeneity and limited resources of wireless networks and mobile devices, networked communications between distributed applications, dynamic discovery and automatic deployment on mobile devices. In this paper, we present a component-based software infrastructure to design, discover, deploy, and execute ubiquitous contextual services, i.e. distributed applications providing services to mobile end-users but only available from a particular place. These ubiquitous contextual services are designed as assemblies of distributed software components. These assemblies are dynamically discovered according to end-users physical location and device capabilities. Then, appropriate assemblies are automatically deployed on users devices. We have implemented this approach (the software infrastructure and a ubiquitous application example) on top of the OMG CORBA Component Model and the OpenCCM open source platform

Deploying on the Grid with DeployWare

In this paper, we present DeployWare to address the deployment of distributed and heterogeneous software systems on large scale infrastructures such as grids. Deployment of software systems on grids raises many challenges like: 1) the complexity to take into account orchestration of all the deployment tasks and management of software dependencies; 2) the heterogeneity of both physical infrastructures and software composing the system to deploy; 3) the validation to early detect errors before concrete deployments; and 4) scalability to tackle thousands of nodes. To address these challenges, DeployWare provides a metamodel that abstracts concepts of the deployment, a virtual machine that executes deployment processes on grids from DeployWare descriptions, and a graphical console that allows to manage deployed systems, at runtime. To validate our approach, we have experimented DeployWare with a lot of software technologies, such as CORBA and SOA-based systems, on one thousand of nodes of Grid5000, the french experimental grid infrastructure.

A component framework for java-based real-time embedded systems

The Real-Time Specification for Java (RTSJ) [13] is becoming a popular choice in the world of real-time and embedded programming. However, RTSJ introduces many non-intuitive rules and restrictions which prevent its wide adoption. Moreover, current state-of-the-art frameworks usually fail to alleviate the development process into higher layers of the software development life-cycle. In this paper we extend our philosophy that RTSJ concepts need to be considered at early stages of software development, postulated in our prior work [2], in a framework that provides continuum between the design and implementation process. A component model designed specially for RTSJ serves here as a cornerstone. As the first contribution of this work, we propose a development process where RTSJ concepts are manipulated independently of functional aspects. Second, we mitigate complexities of RTSJ-development by automatically generating execution infrastructure where real-time concerns are transparently managed. We thus allow developers to create systems for variously constrained real-time and embedded environments. Performed benchmarks show that the overhead of the framework is minimal in comparison to manually written object-oriented applications, while providing more extensive functionality. Finally, the framework is designed with the stress on dynamic adaptability of target systems, a property we envisage as a fundamental in an upcoming era of massively developed real-time systems.

ESB federation for large-scale SOA

Embracing service-oriented architectures in the context of large systems, such as the Web, rises a set of new and challenging issues: increased size and load in terms of users and services, distribution, and dynamicity. A top-down federation of service infrastructure support that we name service cloud and that is capable of growing to the scale of the Internet, is seen as a promising response to such new challenges. In this paper, we define the service cloud concept, its promises and the requirements in terms of architecture and the corresponding middleware. We present some preliminary proofs of concept through the integration of a JBI-compliant enterprise service bus, extended to our needs, and a scalable semantic space infrastructure, both relying on an established grid middleware environment. The new approach offers service consumers and providers a fully transparent, distributed and federated means to access, compose and deploy services on the Internet. Technically, our contribution advances core service bus technology towards the service cloud by scaling the registries and message routers to the level of federations via a hierarchical approach, and by incorporating the communication and coordination facilities offered by a global semantic space.

A generic deployment framework for grid computing and distributed applications

Deployment of distributed applications on large systems, and especially on grid infrastructures, becomes a more and more complex task Grid users spend a lot of time to prepare, install and configure middleware and application binaries on nodes, and eventually start their applications The problem is that the deployment process is composed of many heterogeneous tasks that have to be orchestrated in a specific correct order As a consequence, the automatization of the deployment process is currently very difficult to reach To address this problem, we propose in this paper a generic deployment framework allowing to automatize the execution of heterogeneous tasks composing the whole deployment process Our approach is based on a reification as software components of all required deployment mechanisms or existing tools Grid users only have to describe the configuration to deploy in a simple natural language instead of programming or scripting how the deployment process is executed As a toy example, this framework is used to deploy CORBA component-based applications and OpenCCM middleware on one thousand nodes of the French Grid5000 infrastructure.

A Precise Metamodel for Open Cloud Computing Interface

Open Cloud Computing Interface (OCCI) proposes one of the first widely accepted, community-based, open standards for managing any kinds of cloud resources. But as it is specified in natural language, OCCI is imprecise, ambiguous, incomplete, and needs a precise definition of its core concepts. Indeed, the OCCI Core Model has conceptual drawbacks: an imprecise semantics of its type classification system, a nonextensible data type system for OCCI attributes, a vague and limited extension concept and the absence of a configuration concept. To tackle these issues, this paper proposes a precise metamodel for OCCI. This metamodel defines rigourously the static semantics of the OCCI core concepts, of a precise type classification system, of an extensible data type system, and of both extension and configuration concepts. This metamodel is based on the Eclipse Modeling Framework (EMF), its structure is encoded with Ecore and its static semantics is rigourously defined with Object Constraint Language (OCL). As a consequence, this metamodel provides a concrete language to precisely define and exchange OCCI models. The validation of our metamodel is done on the first world-wide dataset of OCCI extensions already published in the literature, and addressing inter-cloud networking, infrastructure, platform, application, service management, cloud monitoring, and autonomic computing domains, respectively. This validation highlights simplicity, consistency, correctness, completeness, and usefulness of the proposed metamodel.

Elasticity in Cloud Computing: State of the Art and Research Challenges

Elasticity is a fundamental property in cloud computing that has recently witnessed major developments. This article reviews both classical and recent elasticity solutions and provides an overview of containerization, a new technological trend in lightweight virtualization. It also discusses major issues and research challenges related to elasticity in cloud computing. We comprehensively review and analyze the proposals developed in this field. We provide a taxonomy of elasticity mechanisms according to the identified works and key properties. Compared to other works in literature, this article presents a broader and detailed analysis of elasticity approaches and is considered as the first survey addressing the elasticity of containers.

Leveraging Component-Based Software Engineering with Fraclet

Component-based software engineering has achieved wide acceptance in the domain of software engineering by improving productivity, reusability and composition. This success has also encouraged the emergence of a plethora of component models. Nevertheless, even if the abstract models of most of lightweight component models are quite similar, their programming models can still differ a lot. This drawback limits the reuse and composition of components implemented using different programming models. The contribution of this article is to introduce Fraclet as a programming model common to several lightweight component models. This programming model is presented as an annotation framework, which allows the developer to annotate the program code with the elements of the abstract component model. Then, using a generative approach, the annotated program code is completed according to the programming model of the component model to be supported by the component runtime environment. This article shows that this annotation framework provides a significant simplification of the program code by removing all dependencies on the component model interfaces. These benefits are illustrated with the Fractal and OpenCOM component models.

Constructing Domain-Specific Component Frameworks through Architecture Refinement

Recently, a plethora of domain-specific component frameworks (DSCF) emerges. Although the current trend emphasizes generative programming methods as cornerstones of software development, they are commonly applied in a costly, ad-hoc fashion. However, we believe that DSCFs share the same subset of concepts and patterns. In this paper we propose two contributions to DSCF development. First, we propose Domain Components --- a high-level abstraction to capture semantics of domain concepts provided by containers, and we identify patterns facilitating their implementation. Second, we develop a generic framework that automatically generates implementation of Domain Components semantics, thus addressing domain-specific services with one unified approach. To evaluate benefits of our approach we have conducted several case studies that span different domain-specific challenges.

Are REST APIs for Cloud Computing Well-Designed? An Exploratory Study

Cloud computing is currently the most popular model to offer and access computational resources and services. Many cloud providers use the REST architectural style (Representational State Transfer) for offering such computational resources. However, these cloud providers face challenges when designing and exposing REST APIs that are easy to handle by end-users and/or developers. Yet, they benefit from best practices to help them design understandable and reusable REST APIs. However, these best practices are scattered in the literature and they have not be studied systematically on real-world APIs. Consequently, we propose two contributions. In our first contribution, we survey the literature and compile a catalog of 73 best practices in the design of REST APIs making APIs more understandable and reusable. In our second ncontribution, we perform a study of three different and well-known REST APIs from three cloud providers to investigate how their APIs are offered and accessed. These cloud providers are Google Cloud Platform, OpenStack, and Open Cloud Computing Interface (OCCI). In particular, we evaluate the coverage of the features provided by the REST APIs nof these cloud providers and their conformance with the best practices for REST APIs design. nOur results show that Google Cloud follows 66% (48/73), OpenStack follows 62% (45/73), and OCCI 1.2 follows 56% (41/73) of the best practices. Second, although these numbers are not necessarily high, partly because of the strict and precise specification of best practices, we showed that cloud APIs reach an acceptable level of maturity.