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Über dieses Buch

This volume contains the technical papers presented in the four high-quality workshops associated with the European Conference on Service-Oriented and Cloud Computing, ESOCC 2014, held in Manchester, UK, in September 2014: 4th International Workshop on Adaptive Services for the Future Internet, WAS4FI 2014, 2nd International Workshop on Cloud for IoT, CLIoT 2014, 2nd International Workshop on Cloud Service Brokerage, CSB 2014, and Seamless Adaptive Multi-cloud Management of Service-based Applications, SeaCloudS Workshop. The 19 revised full papers and 3 short papers were carefully reviewed and selected from 39 submissions. They focus on specific topics in service-oriented and cloud computing domains as cloud computing, service buses, Web services, service-oriented architectures, event-driven architectures, enterprise architectures, business process management, software selection and adaptation.

Inhaltsverzeichnis

Frontmatter

WAS4FI 2014

Frontmatter

4th International Workshop on Adaptive Services for the Future Internet (WAS4FI 2014): Preface

Abstract
The Future Internet has emerged as a new initiative to pave a novel infrastructure linked to objects (things) of the real world to meet the changing global needs of business and society. It offers internet users a standardized, secure, efficient and trustable environment, which allows open and distributed access to global networks, services and information. There is a need for both researchers and practitioners to develop platforms made up of adaptive Future Internet applications. In this sense, the emergence and consolidation of Service-Oriented Architectures (SOA), Cloud Computing and Wireless Sensor Networks (WSN) give benefits, such as flexibility, scalability, security, interoperability, and adaptability, for building these applications.
Javier Cubo, Juan Boubeta-Puig, Howard Foster, Winfried Lamersdorf, Nadia Gámez

Matching of Incomplete Service Specifications Exemplified by Privacy Policy Matching

Abstract
Service matching approaches determine to what extent a provided service matches a requester’s requirements. This process is based on service specifications describing functional (e.g., signatures) as well as non-functional properties (e.g., privacy policies). However, we cannot expect service specifications to be complete as providers do not want to share all details of their services’ implementation. Moreover, creating complete specifications requires much effort. In this paper, we propose a novel service matching approach taking into account a service’s signatures and privacy policies. In particular, our approach applies fuzzy matching techniques that are able to deal with incomplete service specifications. As a benefit, decision-making based on matching results is improved and service matching becomes better applicable in practice.
Marie Christin Platenius, Svetlana Arifulina, Ronald Petrlic, Wilhelm Schäfer

Implementing Elastic Capacity in a Service-Oriented PaaS

Abstract
In their quest for elastic capacity that balances resource lease at the infrastructure level with quality of service at the top, SaaS providers have a hard time at mapping application requirements onto infrastructure performance indicators. The role of a pure service-oriented platform layer to that regard has not been completely investigated and still less exploited. In this paper we illustrate a case study in which we enabled elastic scalability within an existing SOA cloud platform prototype: PaaSSOA. The latter integration and its subsequent tests allowed us to demonstrate the potential benefits arising from exploiting SOA and PaaS capabilities together, especially to release SaaS providers from the burden of reserving infrastructure capacity to met SLAs and of managing web application.
Alberto Zuccato, Tullio Vardanega

Towards Compensable SLAs

Abstract
Service Level Agreements (SLA) describe the rights and obligations of parties involved (typically the service consumer and the service provider); amongst other information they could include the definition of compensations: penalties and/or rewards depending on the level of service provided. We coin the concept of Compensable SLAs to such that include compensation information inside. In such a context, in spite of important steps towards the automation of the management of SLAs have been given, the expression of compensations remains as an important challenge to be addressed. In this paper we aim to provide a characterization model to create Compensable SLAs; specifically, the main contributions include: (i) the conceptualization of the Compensation Function to express consistently penalties and rewards. (ii) a model for Compensable SLAs as a set of guarantees that associate Service Level Objectives with Compensation Functions. We provide some properties and aspects that have been used to analyse two real-world SLAs.
Carlos Müller, Antonio Manuel Gutierrez, Manuel Resinas, Pablo Fernandez, Antonio Ruiz-Cortés

Service Network Modeling: A Generic Approach

Abstract
With the broad adoption of service-orientation for the realization of business applications and their provisioning and usage over open cloud infrastructures, the topology of the resulting service networks is becoming extremely complex. Due to the composition of services for value-added business capabilities and the reusability of a service in multiple compositions, the execution of one service often depends on other services and changes in its provisioning can affect the health of large parts of the service network. The lack of insight on the relationships between the network components makes the management of the service network’s health and change impact hard and error prone tasks. This paper proposes a service network modeling approach for capturing the topology of a service network at design time. The model is used to validate the health of the service network to ensure the operability of its services. At run time the model can be applied for analyzing the effects of evolutionary events such as service modification or withdrawal. Our major contributions are a generic and adaptable modeling structure and a classification of service network entities and relationships. The applicability of our approach is demonstrated on an example service network scenario.
Aneta Kabzeva, Joachim Götze, Paul Müller

Context-Aware Decentralization Approach for Adaptive BPEL Process in Cloud

Abstract
When outsourcing BPEL process in the Cloud, the decentralization of its execution can resolve any QoS degradation inherent to the centralized execution. Each task within the BPEL process can be executed on a virtual machine (VM) then all tasks are orchestrated together to respect the business process logic constraint represented through the tasks’ dependencies and communication requirements. The BPEL process decentralization must account for a set of contextual information such as the dynamic availability of the Cloud provider’s resources and the customer QoS preferences. So, in this paper, we present a decentralization approach which accounts for several essential factors that best represent the context of the BPEL process when it is outsourced into the Cloud in order to dynamically adapts its initial configuration.
Molka Rekik, Khouloud Boukadi, Hanene Ben-Abdallah

Assisting Business Process Outsourcing to the Cloud

Abstract
The business/IT alignment is an important concept as it creates a coherence between business goals and vision and the IT strategies and decisions. The adoption of cloud computing is one of the IT strategies that is increasingly being considered by several enterprises. When enterprises focalize on the business process outsourcing to the cloud, many issues should be tackled such as its suitability as an environment for running the business process, the selection of parts of business process to be outsourced, and the depiction of the most suitable cloud providers for its execution. This papers major contribution is a decision method framework presenting guidelines to support decision makers aiming to outsource their SOA-based business process to the cloud. The framework assists experts in the fastidious task of analyzing and resolving the BPO problem and its relevance to enterprises context. Its top-down characteristic allows for the study of the enterprise business needs, lacks, and perspectives and the depiction of the implied IT resources creating thus a harmonious correspondence between the two levels which is very demanded in enterprises to guarantee their persistence in the economic markets.
Mouna Rekik, Khouloud Boukadi, Hanene Ben-Abdallah

CLIoT 2014

Frontmatter

Preface of CLIoT

Abstract
The Internet of Things (IoT) is an emerging paradigm that aims to represent the physical world, change the way we interact with the things around us. IoT describes every system through uniquely identifiable and interconnected objects (things). Things have the capacity for sensing, processing or actuating information about entities available from within the real world. Thus, information travels along heterogeneous systems, such as routers, databases, information systems and the Internet, leading in the generation and movement of enormous amounts of data which have to be stored, processed and presented in a seamless, efficient and easily interpretable form. At the same time, Cloud Computing is quickly becoming a pervasive technology, able to offer several types of services according to different business models.
Maria Fazio, Nik Bessis, Massimo Villari

Decentralized Planning for Self-Adaptation in Multi-cloud Environment

Abstract
The runtime management of Internet of Things (IoT) oriented applications deployed in multi-clouds is a complex issue due to the highly heterogeneous and dynamic execution environment. To effectively cope with such an environment, the cross-layer and multi-cloud effects should be taken into account and a decentralized self-adaptation is a promising solution to maintain and evolve the applications for quality assurance. An important issue to be tackled towards realizing this solution is the uncertainty effect of the adaptation, which may cause negative impact to the other layers or even clouds. In this paper, we tackle such an issue from the planning perspective, since an inappropriate planning strategy can fail the adaptation outcome. Therefore, we present an architectural model for decentralized self-adaptation to support the cross-layer and multi-cloud environment. We also propose a planning model and method to enable the decentralized decision making. The planning is formulated as a Reinforcement Learning problem and solved using the Q-learning algorithm. Through simulation experiments, we conduct a study to assess the effectiveness and sensitivity of the proposed planning approach. The results show that our approach can potentially reduce the negative impact on the cross-layer and multi-cloud environment.
Azlan Ismail, Valeria Cardellini

A Graph-Based Cloud Architecture for Big Stream Real-Time Applications in the Internet of Things

Abstract
The Internet of Things (IoT) will consist of billions of interconnected heterogeneous devices denoted as “smart objects.” Smart objects are generally sensor/actuator-equipped and have constrained resources in terms of: (i) processing capabilities; (ii) available ROM/RAM; and (iii) communication reliability. To meet low-latency requirements, real-time IoT applications must rely on specific architectures designed in order to handle and process gigantic (in terms of number of sources of information and rate of received data) streams of data coming from smart objects. We refer to this smart object-generated data stream as “Big Stream,” in contrast to traditional “Big Data” scenarios, where real-time constraints are not considered. In this paper, we propose a novel Cloud architecture for Big Stream applications that can efficiently handle data coming from deployed smart objects through a graph-based processing platform and deliver processed data to consumer applications with lowest latency.
Laura Belli, Simone Cirani, Gianluigi Ferrari, Lorenzo Melegari, Marco Picone

An Approach to Evaluate Applications Running on Web-Based Remote Virtual Machines in Cloud Computing

Abstract
The exploitation of remote Virtual Machines (VM) over the Cloud gives new opportunities to both business and private clients for extending their processing and storage infrastructures. Typically, a remote VM can be accessed through consolidated technologies based on SSH or Remote Desktop Viewer. Regarding Remote Desktop Viewer, several solutions are emerging on the market to access remote VMs via web. However, evaluating performance of desktop applications running on remote VMs is quite hard, because CPU clocks of VMs are typically misaligned from physical devices. In addition, the overhead due to network latency can considerably degrade performance in terms of application responsivity. In this paper, we propose a new methodology that can help scientists and software developers to evaluate performance of applications running on Remote Web-Based VMs (RWVMs) over the Cloud by means of estimating the LAtency Gap (LAG). We use such a methodology to analyze the behavior of a Cloud IaaS considering two different applications running on RWVMs, which can be widely adopted for IoT purposes.
Davide Mulfari, Antonio Celesti, Maria Fazio, Massimo Villari

CSB 2014

Frontmatter

Cloud Service Brokerage - 2014: Towards the Multi-cloud Ecosystem

Abstract
In the future multi-cloud ecosystem, many cloud providers and consumers will interact to create, discover, negotiate and use software services. Cloud service brokers will play a central role in bringing providers and consumers together, assisting with software service creation (from abstract models to platform-specific deployments), multi-cloud translation (model-driven adaptation and deployment of services) quality assurance (governance; functional testing and monitoring), service continuity (failure prevention and recovery) and market competition (arbitrage; service optimization; service customization). The emerging ecosystem will be supported by common standards, service models, methods and mechanisms that will operate across a wide variety of platforms and infrastructure, and across disparate service protocols.
Anthony J. H. Simons, Alessandro Rossini, Iraklis Paraskakis, Jens Jensen

Towards a Model-Based Execution-Ware for Deploying Multi-cloud Applications

Abstract
The current cloud landscape is highly heterogeneous caused by a vast number of cloud offerings by different providers. This hinders the selection of a cloud provider and its divergent offerings based on the requirements of an application and ultimately its deployment. This paper introduces a model based execution-ware that helps coping with these challenges by allowing the deployment of applications in a multi-cloud environment, based on a high-level model created by the user. Based on our experiences with building an initial prototype, we discuss the fundamental challenges and solution approaches that the multi-cloud environment holds.
Daniel Baur, Stefan Wesner, Jörg Domaschka

A Development Framework Enabling the Design of Service-Based Cloud Applications

Abstract
Cloud application platforms gain popularity and have the potential to change the way applications are developed, involving composition of platform basic services. In order to enhance the developer’s experience and reduce the barriers in the software development, a new paradigm of cloud application creation should be adopted. According to that developers are enabled to design their applications, leveraging multiple platform basic services, independently from the target application platforms. To this end, this paper proposes a development framework for the design of service-based cloud applications comprising two main components: the meta-model and the Platform Service Manager. The meta-model describes the building blocks which enable the construction of Platform Service Connectors in a uniform way while the Platform Service Manager coordinates the interaction of the application with the concrete service providers and further facilitates the administration of the deployed platform basic services.
Fotis Gonidis, Iraklis Paraskakis, Anthony J. H. Simons

Cloud Computing Reduces Uncertainties in Quality-of-Service Matching!

Abstract
Cloud computing resulted in a continuously growing number of provided software services to be used by consumers. Brokers discover services that fit best to consumers’ requirements by matching Quality-of-Service (QoS) properties. In order to negotiate Service-Level Agreements (SLAs), a provider has to determine the provided QoS based on QoS analyses. However, the risk for the provider to violate the SLA is high as the service’s actual quality can deviate from the specified QoS due to uncertainties that occur during the provider’s quality analysis. In this paper, we discuss current software engineering paradigms like cloud computing and service-oriented computing with respect to the amount of uncertainty they induce into service matching and SLA negotiations. As a result, we explain, why cloud computing reduces such uncertainties.
Matthias Becker, Marie Christin Platenius, Steffen Becker

Contract Design for Composed Services in a Cloud Computing Environment

Abstract
In this paper, we study markets in which sellers and buyers interact with each other via an intermediary. Our motivating example is a market with a cloud infrastructure where single services are flexibly combined to composed services. We address the contract design problem of an intermediary to purchase complementary single services. By using a non-cooperative game-theoretic model, we analyze the incentives for high- and low-quality composed services to be an equilibrium outcome of the market. It turns out that equilibria with low quality can be obtained in the short run and in the long run, whereas those with high quality can only be achieved in the long run. In our analysis we explicitly determine the according discount factors needed in an infinitely repeated game. Furthermore, we derive optimal contracts for the supply of high- and low-quality composed services.
Sonja Brangewitz, Claus-Jochen Haake, Jochen Manegold

X-Machine Based Testing for Cloud Services

Abstract
In this article we present a tool designed for cloud service testing, able to generate test cases from a formal specification of the service, in form of a deterministic stream X-machine (DSXM) model. The paper summarizes the theoretical foundations of X-machine based testing and illustrates the usage of the developed tool on some examples. It shows in detail how the specification should be written, which are the design for test conditions it should satisfy, in order to assure the generation of high quality test suites for the cloud service.
Raluca Lefticaru, Anthony J. H. Simons

Model-Based Testing for Composite Web Services in Cloud Brokerage Scenarios

Abstract
Cloud brokerage is an enabling technology allowing various services to be merged together for providing optimum quality of service for the end-users. Within this collection of composed services, testing is a challenging task which brokers have to take on to ensure quality of service. Most Software-as-a-Service (SaaS) testing has focused on high-level test generation from the functional specification of individual services, with little research into how to achieve sufficient test coverage of composite services. This paper explores the use of model-based testing to achieve testing of composite services, when two individual web services are tested and combined. Two example web services – a login service and a simple shopping service – are combined to give a more realistic shopping cart service. This paper focuses on the test coverage required for testing the component services individually and their composition. The paper highlights the problems of service composition testing, requiring a reworking of the combined specification and regeneration of the tests, rather than a simple composition of the test suites; and concludes by arguing that more work needs to be done in this area.
Mariam Kiran, Anthony J. H. Simons

Towards a Generic Language for Scalability Rules

Abstract
The PaaSage project aims at facilitating the specification and execution of cloud-based applications by leveraging upon model-driven engineering (MDE) techniques and methods, and by exploiting multiple cloud infrastructures and platforms. Models are frequently specified using domain-specific languages (DSLs), which are tailored to a specific domain of concern. In order to cover the necessary aspects of the specification and execution of multi-cloud applications, PaaSage encompasses a family of DSLs called Cloud Application Modelling and Execution Language (CAMEL). In this paper, we present one DSL within this family, namely the Scalability Rules Language (SRL), which can be regarded as a first step towards a generic language for specifying scalability rules for multi-cloud applications.
Jörg Domaschka, Kyriakos Kritikos, Alessandro Rossini

Linked USDL Business Policy Specifications as WS-Agreement Templates

Abstract
With the increasing adoption of cloud computing, the enterprise IT environment is progressively transformed into a complex ecosystem of diverse interrelated services typically delivered by a multitude of providers. Such complexity calls for service governance and quality control activities. Ideally, such activities must be performed in a generic and platform-agnostic manner, one which demands an ontology-based approach for the specification and enforcement of the relevant governance policies and the service-level objectives that they entail. At the same time, such governance policies must be expressed in a suitable serialisation format in order to be exposed to the relevant stakeholders and, ultimately, form the basis of Service Level Agreements (SLAs). This paper presents an approach for the automatic translation of governance policies expressed in Linked USDL, our chosen ontological framework, into WS-Agreement templates.
Ioannis Arampatzis, Simeon Veloudis, Iraklis Paraskakis

Derivation of Broker Policies from Cloud Hosting Platform Service Descriptions

Abstract
Cloud service brokerage leads to creation of ecosystems of highly distributed, task-oriented, modular, and collaborative cloud services managed by a broker. A broker is striving to create optimized cloud service consumption lifecycle in terms of cost, flexibility and business agility. In order to effectively manage the complexity inherent in such ecosystems, enterprises are anticipated to crucially depend upon cloud service brokerage (CSB) mechanisms. This work focuses on the management of hosting platforms participating in the ecosystem of a cloud service brokerage platform. The hosting platforms are as any other actor of a cloud service brokerage ecosystem evolving over time. The hosting platforms may join or leave the ecosystem, add or remove hosting services to the ecosystem or change characteristics of the available hosting services. The broker is thereby confronted with the issue of keeping its business policy offered to the service providers and service consumers up to date concerning the hosting alternatives in the ecosystem. We present a strategy for derivation of business policies from service descriptions of hosting services. The strategy is showcased in Linked USDL – our chosen technical specification for enabling platform-agnostic data exchanges.
Andreas Friesen, Simeon Veloudis, Iraklis Paraskakis

SeaCloudS 2014

Frontmatter

Workshop on Seamless Adaptive Multi-cloud Management of Service-Based Applications (SeaCloudS): Preface

Abstract
Deploying and managing in an efficient and adaptive way complex service-based applications across multiple heterogeneous clouds is one of the problems that have emerged with the cloud revolution. The current lack of universally accepted standards supporting cloud interoperability is severely affecting the portability of cloud-based applications across different platforms. The objective of the workshop was to provide a forum to discuss problems, solutions and perspectives of ongoing research activities aimed at enabling an efficient and adaptive management of service-based applications across multiple clouds.
Antonio Brogi, Ernesto Pimentel

Orthogonal Variability Modeling to Support Multi-cloud Application Configuration

Abstract
Cloud service providers benefit from a vast majority of customers due to variability and making profit from commonalities between the cloud services that they provide. Recently, application configuration dimensions has been increased dramatically due to multi-tenant, multi-device and multi-cloud paradigm. This challenges the configuration and customization of cloud-based software that are typically offered as a service due to the intrinsic variability. In this paper, we present a model-driven approach based on variability models originating from the software product line community to handle such multi-dimensional variability in the cloud. We exploit orthogonal variability models to systematically manage and create tenant-specific configuration and customizations. We also demonstrate how such variability models can be utilized to take into account the already deployed application parts to enable harmonized deployments for new tenants in a multi-cloud setting. The approach considers application functional and non-functional requirements to provide a set of valid multi-cloud configurations. We illustrate our approach through a case study.
Pooyan Jamshidi, Claus Pahl

A Marketplace Broker for Platform-as-a-Service Portability

Abstract
Platform as a Service (PaaS) has become a strong technological solution in particular for small medium enterprises (SMEs) to achieve cost savings and rapid time to market of their software solutions. However, for SMEs how to choose the PaaS provider becomes a bottleneck due to the number of offerings each PaaS vendor offers. Another challenge often faced by enterprises is how to match their software system requirements to PaaS offerings. Furthermore, searching for the best PaaS offering is even more difficult when enterprises need to migrate their existing software solutions from one PaaS vendor to another. In such cases, the portability of the enterprises data and application components becomes cumbersome. If their software solutions are bound to a specific PaaS provider, enterprises suffer from vendor lock-in. This paper addresses these portability challenges by proposing a high-level architecture to ease the portability of software solutions over PaaS vendors taking into consideration the various life-cycle stages, such as identifying and analysing Paas offerings in the market; selecting the best PaaS offering according to organisation’s requirements; and the deployment, management, and monitoring of the software solutions.
Bholanathsingh Surajbali, Adrián Juan-Verdejo

Towards a Classification of Multiple-Cloud Computing Concepts and Terms

Abstract
In order to enhance the quality of the delivered services, dependency avoidance, and operational costs optimization, the multiple-cloud computing emerged. The complexity of multiple-clouds causes a lot of opacity in the definitions and classifications. This paper attempts to provide an accurate definition of the multiple-clouds and, a classification of the available types based on a set of pre-defined criteria. It also outlines the differences between the terms that have been used to refer to the multiple-cloud computing concept.
Hassan Saad Alqahtani, Ghita Kouadri-Mostefaoui

Towards a Flexible Deployment of Multi-cloud Applications Based on TOSCA and CAMP

Abstract
Cloud Computing platforms offer diverse services and capabilities with own features. Hence, the provider services could be used by end users to compose a heterogeneous context of multiple cloud platforms in order to deploy their cloud applications made up of a set of modules, according to the best capabilities of the cloud providers. However, this is an ideal scenario, since the cloud platforms are being conducted in an isolated way by presenting many interoperability and portability restrictions, which complicate the integration of diverse provider services to achieve an heterogeneous deployment of multi-cloud applications. In this ongoing work, we present an approach based on model transformation to deploy multi-cloud applications by reusing standardization efforts related to the management and deployment of cloud applications. Specifically, using mechanisms specified by both standards, TOSCA and CAMP, we propose a methodology to describe the topology and distribution of modules of a cloud application and to deploy the interconnected modules over heterogeneous clouds. We illustrate our idea using a running example.
Jose Carrasco, Javier Cubo, Ernesto Pimentel

Backmatter

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