Data Storage in Cloud Based Real-Time Environments

The service oriented infrastructures for real-time applications (“real-time clouds1”) pose certain unique challenges for the data storage subsystem, which indeed is the “last mile” for all data accesses. Data storage subsystems typically used in regular enterprise environments have many limitations which impedes direct applicability for such clouds, particularly in their ability to provide Quality of Service (QoS) for applications. Provision of QoS within storage is possible through a deeper understanding of the behaviour of the storage system under a variety of conditions dictated by the application and the network infrastructure. We intend to arrive at a QoS mechanism for data storage keeping in view the important parameters that come into play for the storage subsystem in a soft real-time cloud environment.

Real-Time Attributes in Operating Systems

General-Purpose Operating Systems (GPOSes) are being used more and more extensively to support interactive, real-time, and distributed applications, as found in the multimedia domain. In fact, the wide availability of supported multimedia devices and protocols, together with the wide availability of libraries and tools for handling multimedia contents, make them an almost ideal platform for the development of this kind of complex applications. However, contrarily to Real-Time Operating Systems, General-Purpose ones used to lack some important functionality needed for providing proper scheduling guarantees to application processes. Recently, the increasing use of GPOSes for multimedia applications is gradually pushing OS developers towards enriching the kernel of a GPOS so as to provide more and more real-time functionality, thus enhancing the performance and responsiveness of hosted time-sensitive applications. In this chapter, an overview is performed over the efforts done in the direction of enriching GPOSes with real-time capabilities, with a particular focus on the Linux OS. Due to its open-source nature and wide diffusion and availability, Linux is one of the most widely used OSes for such experimentations.

Network Management in Virtualized Infrastructures

This chapter provides an overview on related state of the art technologies regarding topics such as QoS provisioning, virtualization, and network resource management. This background is enriched with latest research results on future trends and advances in state of the art in network management.

Fault Detection and Recovery Mechanisms and Techniques for Service Oriented Infrastructures

The need for guaranteed QoS and efficient management in Service Oriented Infrastructures is an essential requirement for the deployment, execution, and management of modern business applications. In that frame, the capabilities for fault detection and recovery in all layers of a Service Oriented Infrastructure are essential for the smooth operation of the business applications and the wide adoption of these solutions in the global market. In this chapter, we present the concepts of fault detection and recovery, including terminology, classification of faults, and analysis of the key processes taking place in a system in order to diagnose and recover from failures. The state of the art mechanisms and techniques for fault detection and recovery are also analyzed, while recommendations for applying them in Service Oriented Infrastructure are presented.

Programming Interfaces for Realtime and Cloud-Based Computing

The appearance of different business roles according to this classification, potentially with differing interests, introduces new challenges with regard to the tools and mechanisms put in place in order to enable the efficient provisioning of services. Security, Quality of Service (QoS) assurance, and real-time capabilities are just a few issues that the providers are trying to tackle and integrate within the new products and services that they offer. In this chapter, we make an overview of the approaches that aim to APIs for real-time computing. In the first part of this chapter, several Real-Time Application Interfaces will be presented and compared. After that, we will document the state-of-the-art regarding the Cloud APIs available and analyze the architecture and the technologies that they support.

Model-Driven Engineering, Services and Interactive Real-Time Applications

Model-driven software engineering (MDE) has the basic assumption that the development of software systems from high-level abstractions along with the generation of low-level implementation code can improve the quality of the systems and at the same time reduce costs and improve time to market. This chapter provides an overview of MDE, state of the art approaches, standards, resources, and tools that support different aspects of model-driven software engineering: language development, modeling services, and real-time applications. The chapter concludes with a reflection over the main challenges faced by projects using the current MDE technologies, pointing out some promising directions for future developments.

Securing Real-Time Interactive Applications in Federated Clouds

Enterprise adoption of cloud computing for real-time interactive applications processes is limited by their ability to meet inter-enterprise security requirements. Although some clouds’ offerings comply with security standards, no solution today allows businesses to assess security compliance of applications at the business level and dynamically link to security countermeasures on-demand. In this chapter we examine cloud security, privacy, and trust issues from three levels: business, jurisdiction, and technical. Firstly, we look at the business level to identify issues arising from the motivations and concerns of business stakeholders. Secondly, we explore jurisdictional level to identify risks that arise from legislation, gaps in legislation, or conflicts between legislation in different jurisdictions related to a cloud deployment, given the concerns of stakeholders. Finally, we examine the technical level to identify issues that arise from technical causes such as ICT vulnerabilities, and/or require technical solutions, such as data confidentiality and integrity protection.

Modelling and Analysing QoS for Real-Time Interactive Applications on the Cloud

The complexity of determining resource provisioning policies for applications in such complex environments introduces significant inefficiencies in the cloud. Novel approaches are needed to efficiently model and analyse Quality of Service for such applications, especially those with real-time constraints. This chapter investigates some of the techniques that can be used to explore these trade-offs and to find business models where value can be provided at all stages in the value-chain. For example, how can an application user identify a set of service providers that provide the best solution to their workflow in combination? How much risk is involved, e.g. what is the probability and impact of a failure of a service provider to deliver the QoS they promise? How can Service Level Agreements be specified that provide the flexibility to accommodate variability in service use, yet don’t result in unnecessarily high cost to the consumer due to the service provider having to use massive over-provisioning of resources to ensure they can meet times of peak-load?

Taxonomy and State of the Art of Service Discovery Mechanisms and Their Relation to the Cloud Computing Stack

Service Discovery mechanisms are gaining interest in the last years due to the growing bulk of information available, especially to distributed computing infrastructures like Grids and Clouds. However a vast number of characteristics of these implementations exist, each one suitable for a number of purposes. The aim of this chapter is to extract a taxonomy of these characteristics found in modern Service Discovery systems and produce a categorization of existing implementations in a grouped and comparative way, based on these features. Furthermore, the mapping of these characteristics to the Cloud business model is produced, in order to assist in selecting the suitable solutions for each provider based on his/her location in the value chain or identify gaps in the existing implementations.

Execution and Resource Management in QoS-Aware Virtualized Infrastructures

Both real-time systems and virtualization have been important research topics for quite some time now. Having competing goals, research on the correlation of these topics has started only recently. This chapter overviews recent results in the research literature on virtualized large-scale systems and soft real-time systems. These concepts constitute the fundamental background over which the execution environment of any large-scale service-oriented real-time architecture for highly interactive, distributed, and virtualized applications will be built in the future. While many aspects covered in this chapter have already been adopted in commercial products, others are still under intensive investigation in research labs all over the world.