Platform for reliable computing on clusters using group communications

Shared clusters represent an excellent platform for the execution of parallel applications given their low price/performance ratio and the presence of cluster infrastructure in many organisations. The focus of recent research efforts are on parallelism management, transport and efficient access to resources, and making clusters easy to use. In this thesis, we examine reliable parallel computing on clusters. The aim of this research is to demonstrate the feasibility of developing an operating system facility providing transport fault tolerance using existing, enhanced and newly built operating system services for supporting parallel applications. In particular, we use existing process duplication and process migration services, and synthesise a group communications facility for use in a transparent checkpointing facility. This research is carried out using the methods of experimental computer science. To provide a foundation for the synthesis of the group communications and checkpointing facilities, we survey and review related work in both fields. For group communications, we examine the V Distributed System, the x-kernel and Psync, the ISIS Toolkit, and Horus. We identify a need for services that consider the placement of processes on computers in the cluster. For Checkpointing, we examine Manetho, KeyKOS, libckpt, and Diskless Checkpointing. We observe the use of remote computer memories for storing checkpoints, and the use of copy-on-write mechanisms to reduce the time to create a checkpoint of a process. We propose a group communications facility providing two sets of services: user-oriented services and system-oriented services. User-oriented services provide transparency and target application. System-oriented services supplement the user-oriented services for supporting other operating systems services and do not provide transparency. Additional flexibility is achieved by providing delivery and ordering semantics independently. An operating system facility providing transparent checkpointing is synthesised using coordinated checkpointing. To ensure a consistent set of checkpoints are generated by the facility, instead of blindly blocking the processes of a parallel application, only non-deterministic events are blocked. This allows the processes of the parallel application to continue execution during the checkpoint operation. Checkpoints are created by adapting process duplication mechanisms, and checkpoint data is transferred to remote computer memories and disk for storage using the mechanisms of process migration. The services of the group communications facility are used to coordinate the checkpoint operation, and to transport checkpoint data to remote computer memories and disk. Both the group communications facility and the checkpointing facility have been implemented in the GENESIS cluster operating system and provide proof-of-concept. GENESIS uses a microkernel and client-server based operating system architecture, and is demonstrated to provide an appropriate environment for the development of these facilities. We design a number of experiments to test the performance of both the group communications facility and checkpointing facility, and to provide proof-of-performance. We present our approach to testing, the challenges raised in testing the facilities, and how we overcome them. For group communications, we examine the performance of a number of delivery semantics. Good speed-ups are observed and system-oriented group communication services are shown to provide significant performance advantages over user-oriented semantics in the presence of packet loss. For checkpointing, we examine the scalability of the facility given different levels of resource usage and a variable number of computers. Low overheads are observed for checkpointing a parallel application. It is made clear by this research that the microkernel and client-server based cluster operating system provide an ideal environment for the development of a high performance group communications facility and a transparent checkpointing facility for generating a platform for reliable parallel computing on clusters

Performance measurement and analysis of PC based cluster server using SET of Architecture and modeling a scalable High performance cluster

Not availabl

Cluster Computing: A Novel Peer-to-Peer Cluster for Generic Application Sharing

Ph.DDOCTOR OF PHILOSOPH

A Policy-Based Resource Brokering Environment for Computational Grids

With the advances in networking infrastructure in general, and the Internet in particular, we can build grid environments that allow users to utilize a diverse set of distributed and heterogeneous resources. Since the focus of such environments is the efficient usage of the underlying resources, a critical component is the resource brokering environment that mediates the discovery, access and usage of these resources. With the consumer\u27s constraints, provider\u27s rules, distributed heterogeneous resources and the large number of scheduling choices, the resource brokering environment needs to decide where to place the user\u27s jobs and when to start their execution in a way that yields the best performance for the user and the best utilization for the resource provider. As brokering and scheduling are very complicated tasks, most current resource brokering environments are either specific to a particular grid environment or have limited features. This makes them unsuitable for large applications with heterogeneous requirements. In addition, most of these resource brokering environments lack flexibility. Policies at the resource-, application-, and system-levels cannot be specified and enforced to provide commitment to the guaranteed level of allocation that can help in attracting grid users and contribute to establishing credibility for existing grid environments. In this thesis, we propose and prototype a flexible and extensible Policy-based Resource Brokering Environment (PROBE) that can be utilized by various grid systems. In designing PROBE, we follow a policy-based approach that provides PROBE with the intelligence to not only match the user\u27s request with the right set of resources, but also to assure the guaranteed level of the allocation. PROBE looks at the task allocation as a Service Level Agreement (SLA) that needs to be enforced between the resource provider and the resource consumer. The policy-based framework is useful in a typical grid environment where resources, most of the time, are not dedicated. In implementing PROBE, we have utilized a layered architecture and façade design patterns. These along with the well-defined API, make the framework independent of any architecture and allow for the incorporation of different types of scheduling algorithms, applications and platform adaptors as the underlying environment requires. We have utilized XML as a base for all the specification needs. This provides a flexible mechanism to specify the heterogeneous resources and user\u27s requests along with their allocation constraints. We have developed XML-based specifications by which high-level internal structures of resources, jobs and policies can be specified. This provides interoperability in which a grid system can utilize PROBE to discover and use resources controlled by other grid systems. We have implemented a prototype of PROBE to demonstrate its feasibility. We also describe a test bed environment and the evaluation experiments that we have conducted to demonstrate the usefulness and effectiveness of our approach

Effective interprocess communication (IPC) in a real-time transputer network

The thesis describes the design and implementation of an interprocess communication (IPC) mechanism within a real-time distributed operating system kernel (RT-DOS) which is designed for a transputer-based network. The requirements of real-time operating systems are examined and existing design and implementation strategies are described. Particular attention is paid to one of the object-oriented techniques although it is concluded that these techniques are not feasible for the chosen implementation platform. Studies of a number of existing operating systems are reported. The choices for various aspects of operating system design and their influence on the IPC mechanism to be used are elucidated. The actual design choices are related to the real-time requirements and the implementation that has been adopted is described. [Continues.

Toward Optimizing Distributed Programs Directed by Configurations

Networks of workstations are now viable environments for running distributed and parallel applications. Recent advances in software interconnection technology enables programmers to prepare applications to run in dynamically changing environments because module interconnection activity is regarded as an essentially distinct and different intellectual activity so as isolated from that of implementing individual modules. But there remains the question of how to optimize the performance of those applications for a given execution environment: how can developers realize performance gains without paying a high programming cost to specialize their application for the target environment? Interconnection technology has allowed programmers to tailor and tune their applications on distributed environments, but the traditional approach to this process has ignored the performance issue over gracefully seemless integration of various software components

DIVE on the internet

This dissertation reports research and development of a platform for Collaborative Virtual Environments (CVEs). It has particularly focused on two major challenges: supporting the rapid development of scalable applications and easing their deployment on the Internet. This work employs a research method based on prototyping and refinement and promotes the use of this method for application development. A number of the solutions herein are in line with other CVE systems. One of the strengths of this work consists in a global approach to the issues raised by CVEs and the recognition that such complex problems are best tackled using a multi-disciplinary approach that understands both user and system requirements. CVE application deployment is aided by an overlay network that is able to complement any IP multicast infrastructure in place. Apart from complementing a weakly deployed worldwide multicast, this infrastructure provides for a certain degree of introspection, remote controlling and visualisation. As such, it forms an important aid in assessing the scalability of running applications. This scalability is further facilitated by specialised object distribution algorithms and an open framework for the implementation of novel partitioning techniques. CVE application development is eased by a scripting language, which enables rapid development and favours experimentation. This scripting language interfaces many aspects of the system and enables the prototyping of distribution-related components as well as user interfaces. It is the key construct of a distributed environment to which components, written in different languages, connect and onto which they operate in a network abstracted manner. The solutions proposed are exemplified and strengthened by three collaborative applications. The Dive room system is a virtual environment modelled after the room metaphor and supporting asynchronous and synchronous cooperative work. WebPath is a companion application to a Web browser that seeks to make the current history of page visits more visible and usable. Finally, the London travel demonstrator supports travellers by providing an environment where they can explore the city, utilise group collaboration facilities, rehearse particular journeys and access tourist information data

Light-Weight Remote Communication for High-Performance Cloud Networks

Während der letzten 10 Jahre gewann das Cloud Computing immer weiter an Bedeutung. Um kosten zu sparen installieren immer mehr Anwender ihre Anwendungen in der Cloud, statt eigene Hardware zu kaufen und zu betreiben. Als Reaktion entstanden große Rechenzentren, die ihren Kunden Rechnerkapazität zum Betreiben eigener Anwendungen zu günstigen Preisen anbieten. Diese Rechenzentren verwenden momentan gewöhnliche Rechnerhardware, die zwar leistungsstark ist, aber hohe Anschaffungs- und Stromkosten verursacht. Aus diesem Grund werden momentan neue Hardwarearchitekturen mit schwächeren aber energieeffizienteren CPUs entwickelt. Wir glauben, dass in zukünftiger Cloudhardware außerdem Netzwerkhardware mit Zusatzfunktionen wie user-level I/O oder remote DMA zum Einsatz kommt, um die CPUs zu entlasten. Aktuelle Cloud-Plattformen setzen meist bekannte Betriebssysteme wie Linux oder Microsoft Windows ein, um Kompatibilität mit existierender Software zu gewährleisten. Diese Betriebssysteme beinhalten oft keine Unterstützung für die speziellen Funktionen zukünftiger Netzwerkhardware. Stattdessen verwenden sie traditionell software-basierte Netzwerkstacks, die auf TCP/IP und dem Berkeley-Socket-Interface basieren. Besonders das Socket-Interface ist mit Funktionen wie remote DMA weitgehend inkompatibel, da seine Semantik auf Datenströmen basiert, während remote DMA-Anfragen sich eher wie in sich abgeschlossene Nachrichten verhalten. In der vorliegenden Arbeit beschreiben wir LibRIPC, eine leichtgewichtige Kommunikationsbibliothek für Cloud-Anwendungen. LibRIPC verbessert die Leistung zukünftiger Netzwerkhardware signifikant, ohne dabei die von Anwendungen benötigte Flexibilität zu vernachlässigen. Anstatt Sockets bietet LibRIPC eine nachrichtenbasierte Schnittstelle an, zwei Funktionen zum senden von Daten implementiert: Eine Funktion für kurze Nachrichten, die auf niedrige Latenz optimiert ist, sowie eine Funktion für lange Nachrichten, die durch die Nutzung von remote DMA-Funktionalität hohe Datendurchsätze erreicht. Übertragene Daten werden weder beim Senden noch beim Empfangen kopiert, um die Übertragungslatenz zu minimieren. LibRIPC nutzt den vollen Funktionsumfang der Hardware aus, versteckt die Hardwarefunktionen aber gleichzeitig vor der Anwendung, um die Hardwareunabhängigkeit der Anwendung zu gewährleisten. Um Flexibilität zu erreichen verwendet die Bibliothek ein eigenes Adressschema, dass sowohl von der verwendeten Hardware als auch von physischen Maschinen unabhängig ist. Hardwareabhängige Adressen werden dynamisch zur Laufzeit aufgelöst, was starten, stoppen und migrieren von Prozessen zu beliebigen Zeitpunkten erlaubt. Um unsere Lösung zu Bewerten implementierten wir einen Prototypen auf Basis von InfiniBand. Dieser Prototyp nutzt die Vorteile von InfiniBand, um effiziente Datenübertragungen zu ermöglichen, und vermeidet gleichzeitig die Nachteile von InfiniBand, indem er die Ergebnisse langwieriger Operationen speichert und wiederverwendet. Wir führten Experimente auf Basis dieses Prototypen und des Webservers Jetty durch. Zu diesem Zweck integrierten wir Jetty in das Hadoop map/reduce framework, um realistische Lastbedingungen zu erzeugen. Während dabei die effiziente Integration von LibRIPC und Jetty vergleichsweise einfach war, erwies sich die Integration von LibRIPC und Hadoop als deutlich schwieriger: Um unnötiges Kopieren von Daten zu vermeiden, währen weitgehende Änderungen an der Codebasis von Hadoop erforderlich. Dennoch legen unsere Ergebnisse nahe, dass LibRIPC Datendurchsatz, Latenz und Overhead gegenüber Socketbasierter Kommunikation deutlich verbessert