Andreas Menychtas

Platform-as-a-Service Architecture for Real-Time Quality of Service Management in Clouds

Cloud computing offers the potential to dramatically reduce the cost of software services through the commoditization of information technology assets and on-demand usage patterns. However, the complexity of determining resource provision policies for applications in such complex environments introduces significant inefficiencies and has driven the emergence of a new class of infrastructure called Platform-as-a-Service (PaaS). In this paper, we present a novel PaaS architecture being developed in the EU IST IRMOS project targeting real-time Quality of Service (QoS) guarantees for online interactive multimedia applications. The architecture considers the full service lifecycle including service engineering, service level agreement design, provisioning and monitoring. QoS parameters at both application and infrastructure levels are given specific attention as the basis for provisioning policies in the context of temporal constraints. The generic applicability of the architecture is being verified and validated through implemented scenarios from three important application sectors (film post-production, virtual augmented reality for engineering design, collaborative e-Learning in virtual worlds).

A Self-adaptive hierarchical monitoring mechanism for Clouds

While Cloud computing offers the potential to dramatically reduce the cost of software services through the commoditization of IT assets and on-demand usage patterns, one has to consider that Future Internet applications raise the need for environments that can facilitate real-time and interactivity and thus pose specific requirements to the underlying infrastructure. The latter, should be able to efficiently adapt resource provisioning to the dynamic Quality of Service (QoS) demands of such applications. To this direction, in this paper we present a monitoring system that facilitates on-the-fly self-configuration in terms of both the monitoring time intervals and the monitoring parameters. The proposed approach forms a multi-layered monitoring framework for measuring QoS at both application and infrastructure levels targeting trigger events for runtime adaptability of resource provisioning estimation and decision making. Besides, we demonstrate the operation of the implemented mechanism and evaluate its effectiveness using a real-world application scenario, namely Film Post Production.

An innovative workflow mapping mechanism for Grids in the frame of Quality of Service

The advent of Grid environments made feasible the solution of computational intensive problems in a reliable and cost-effective way. As workflow systems carry out more complex and mission-critical applications, Quality of Service (QoS) analysis serves to ensure that each application meets user requirements. In that frame, we present a novel algorithm which allows the mapping of workflow processes to Grid provided services assuring at the same time end-to-end provision of QoS based on user-defined parameters and preferences. We also demonstrate the operation of the implemented algorithm and evaluate its effectiveness using a Grid scenario, based on a 3D image rendering application.

Migrating Legacy Software to the Cloud with ARTIST

As cloud computing allows improving the quality of software and aims at reducing costs of operating software, more and more software is delivered as a service. However, moving from a software as a product strategy to delivering software as a service hosted in cloud environments is very ambitious. This is due to the fact that managing software modernization is still a major challenge, especially when paradigm shifts, such as moving to cloud environments, are targeted that imply fundamental changes to how software is modernized, delivered, and sold. Thus, in addition to technical aspects, business aspects need also to be considered. ARTIST proposes a comprehensive software modernization approach covering business and technical aspects. In particular, ARTIST employs Model-Driven Engineering (MDE) techniques to automate the reverse engineering of legacy software and forward engineering of cloud-based software in a way that modernized software truly benefits from targeted cloud environments. Therewith, ARTIST aims at reducing the risks, time, and costs of software modernization and lowers the barriers to exploit cloud computing capabilities and new business models.

A Real-time Service Oriented Infrastructure

The advancements in distributed computing have driven the emergence of service-based infrastructures that allow for on-demand provision of ICT assets. Taking into consideration the complexity of distributed environments, significant challenges exist in providing and managing the offered on-demand resources with the required level of Quality of Service (QoS), especially for real-time interactive and streaming applications. In this paper we propose an approach for providing real-time QoS guarantees by enhancing service oriented infrastructures with coherent and consistent real-time attributes at various levels (application, network, storage, processing). The approach considers the full lifecycle of service-based systems including service engineering, Service Level Agreement (SLA) negotiation and management, service provisioning and monitoring. QoS parameters at application, platform and infrastructure levels are given specific attention as the basis for provisioning policies in the context of temporal constraints

Workflow management for soft real-time interactive applications in virtualized environments

Many applications, especially the ones implementing multi-user collaborative environments, fall within the context of soft real-time systems in which only small deviations from timing constraints are allowed. The advancements in distributed computing have made it possible to follow a service oriented approach, taking advantage of the benefits this provides. In this context, applications consist of soft real-time critical application service components that interact with each other to provide the corresponding application functionality, forming application workflows. In this paper we present a new architectural design and implementation of a Workflow Management approach. This approach covers enacting soft real-time application service components according to a workflow description language, synchronizing the application components, monitoring the execution and reacting to events within a distributed virtualized environment. We also demonstrate the operation of the implemented mechanism and evaluate its effectiveness using an application scenario with soft real-time interactivity characteristics, namely Film post-production, under realistic settings.

ElaaS: An Innovative Elasticity as a Service Framework for Dynamic Management across the Cloud Stack Layers

Nowadays the general interest on Cloud Computing as a technical and business solution is growing. The pool of available cloud applications, services and platforms is increasing leveraging new features for the cloud assets provisioned to the end user. This massive amount and divergence of cloud features across the cloud stack layers introduces considerable management overhead to the various stakeholders for the effective management of both the offered products and the system itself. In this paper we focus on the challenges arise for providing dynamic elasticity management as one the fundamental features of Clouds. To this direction, we introduce the concept of Elasticity as a Service and present a generic, service-oriented framework capable to fulfill, in a personalized manner, the elasticity management needs of any cloud environment and cloud-enabled application.

ARTIST Methodology and Framework: A Novel Approach for the Migration of Legacy Software on the Cloud

Nowadays Cloud Computing is considered as the ideal environment for engineering, hosting and provisioning applications. A continuously increasing set of cloud-based solutions is available to application owners and developers to tailor their applications exploiting the advanced features of this paradigm for elasticity, high availability and performance. Although these offerings provide many benefits to new applications, they also incorporate constrains to the modernization and migration of legacy applications by obliging the use of specific technologies and explicit architectural design approaches. The modernization and adaptation of legacy applications to cloud environments is a great challenge for all involved stakeholders, not only from the technical perspective, but also in business level with the need to adapt the business processes and models of the modernized application that will be offered from now on, as a service. In this paper we present a novel model-driven approach for the migration of legacy applications in modern cloud environments which covers all aspects and phases of the migration process, as well as an integrated framework that supports all migration process.

Translation of application-level terms to resource-level attributes across the Cloud stack layers

The emergence of new environments such as Cloud computing highlighted new challenges in traditional fields like performance estimation. Most of the current cloud environments follow the Software, Platform, Infrastructure service model in order to map discrete roles / providers according to the offering in each “layer”. However, the limited amount of information passed from one layer to the other has raised the level of difficulty in translating user-understandable application terms from the Software layer to resource specific attributes, which can be used to manage resources in the Platform and Infrastructure layers. In this paper, a generic black box approach, based on Artificial Neural Networks is used in order to perform the aforementioned translation. The efficiency of the approach is presented and validated through different application scenarios (namely FFMPEG encoding and real-time interactive e-Learning) that highlight its applicability even in cases where accurate performance estimation is critical, as in cloud environments aiming to facilitate real-time and interactivity.

A novel mechanism for provisioning of high-level quality of service information in grid environments

Grids, like other heterogeneous systems, have reached the level of maturity where they are addressing the Quality of Service (QoS) provision aspect as a fundamental part of their architecture. However, due to the multi-layer nature of these environments, the QoS characteristics of the infrastructure are revealed to the service-consumer through a complex procedure, in which each layer maps its own QoS parameters to another. Most of these approaches are starting the delegation of QoS information from the service providers side, resulting in delivering low-level terms to the service consumer. In this paper, we define the architecture of a mechanism that is able to provide application-oriented and user-specific QoS information in the internal layers of the Grid middleware. This way, it enables the service consumer and especially the end-user to express his business perspectives through the service level agreement life cycle. We also demonstrate the operation of this mechanism and evaluate its performance using a specific Grid scenario.