In these days the term virtualization is almost everywhere, especially in relation with server virtualization. One of the main goals is to describe the part of virtualization which is today not so known although it could have the same meaning for companies as the server virtualization had a few years ago. It is a desktop virtualization and this work includes not just a wide description of this but also related technologies such as data storage virtualization, application virtualization and cloud computing. Another goal is to hold desktop virtualization and find its benefits by placing into the area of small and medium businesses. Thesis is not focused only on the positives of using this technology but also on overall aspects of its use including related risks. Entire part of this thesis is business plan of the company that currently offers virtualization as a complex service for small and medium enterprises. Essential is not just a complete description of the fast growing area, but also concept the practical filling by the plan, which is in the acceptable form for potential investor.

Telecom service providers are adopting a Network Functions Virtualization (NFV) based service delivery model, in response to the unprecedented traffic growth and an increasing customers demand for new high-quality network services. In NFV, telecom network functions are virtualized and run on top of commodity servers. Ensuring network performance equivalent to the legacy non-virtualized system is a determining factor for the success of telecom networks virtualization. Whereas in virtualized systems, achieving carrier-grade network performance such as low latency, high throughput, and high availability to guarantee the quality of experience (QoE) for customer is challenging. In this thesis, we focus on addressing the latency challenge. We investigate the delay overhead of virtualization by comprehensive network performance measurements and analysis in a controlled virtualized environment. With this, a break-down of the latency incurred by the virtualization and the impact of co-locating virtual machines (VMs) of different workloads on the end-to-end latency is provided. We exploit this result to develop an optimization model for placement and provisioning of the virtualized telecom network functions to ensure both the latency and cost-efficiency requirements. To further alleviate the latency challenge, we propose a multipath transport protocol MDTCP, that leverage Explicit Congestion Notification (ECN) to quickly detect and react to an incipient congestion to minimize queuing delays, and achieve high network utilization in telecom datacenters. / HITS, 4707

Magistro darbe apžvelgiamos virtualizavimo programos. Nustatomi jų trūkumai ir privalumai kuriant virtualizavimo infrastruktūra įmonės IT skyriui. Parenkamas tinkamiausias virtualizavimo būdas IT skyriui. / Due to the flexibility of virtualization there is a good chance that there is a virtual design or system to meet the most demanding needs and because of this virtualization is merely duplicating the revolution in open systems by supplying a wide variety of solutions and meet any IT needs.

GPUs offer high-performance floating-point computation at commodity prices, but their usage is hindered by programming models which expose the user to irregularities in the current shared-memory environments and require learning new interfaces and semantics. This thesis will demonstrate that the message-passing paradigm can be conceptually cleaner than the current data-parallel models for programming GPUs because it can hide the quirks of current GPU shared-memory environments, as well as GPU-specific features, behind a well-established and well-understood interface. This will be shown by demonstrating a proof-of-concept MPI implementation which provides cleaner, simpler code with a reasonable performance cost. This thesis will also demonstrate that, although there is a virtualization constraint imposed by MPI, this constraint is harmless as long as the virtualization was already chosen to be optimal in terms of a strong execution model and nearly-optimal execution time. This will be demonstrated by examining execution times with varying virtualization using a computationally-expensive micro-kernel.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第22809号 / 情博第739号 / 新制||情||126(附属図書館) / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 大木 英司, 教授 守倉 正博, 教授 原田 博司 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

This master’s thesis explains why certain network services are difficult to provision and configure using IT automation and cloud orchestration software. An improvement is proposed and motivated. This proposed improvement enables network operators to define a set of data models describing how to provision and interconnect a set of Virtual Network Functions (VNFs) (and possibly existing physical network functions) to form networks. Moreover, the proposed solution enables network operators to change the configuration at runtime. The work can be seen as a step towards self managing and auto scaling networks. The proposed approach is compared to a well known cloud management system (OpenStack) in order to evaluate if the proposed approach decreases the amount of time needed for network operators to design network topologies and services containing VNFs. Data is collected through observations of network operators, interviews, and experiment. Analysis of this data shows that the proposed approach can decrease the amount of time required for network operators to design network topologies and services. This applies if the network operators are already acquainted with the data modeling language YANG. The amount of time required to provision VNFs so that they respond to connections can also be decreased using the proposed approach. The proposed approach does not offer as much functionality as OpenStack, as it is limited to VNF scenarios. / Denna masteruppsats förklarar varför vissa nätverkstjänster är svåra att skapa och konfigurera med IT-automationsverktyg och mjukvara för molnorkestrering.  En förbättring föreslås och motiveras. Den föreslagna förbättringen tillåter nätverksoperatörer att definiera en mängd datamodeller, för att beskriva hur Virtuella Nätverksfunktioner (VNF:er) skall instantieras och kopplas ihop till nätverkstjänster. Dessutom tillåter lösningen nätverksoperatörer att ändra konfiguration under tiden nätverken hanterar trafik.  Arbetet kan ses som ett steg mot självhanterande och automatiskt skalande nätverk. Den föreslagna lösningen jämförs med ett välkänt molnorkestreringsverktyg (OpenStack) för att utvärdera om den föreslagna lösningen sänker mängden tid som nätverksoperatörer behöver för att designa nätverkstopologier och tjänster som innehåller VNF:er. Data samlas in genom observationer av nätverksoperatörer, intervjuer, och experiment. Analys av datan visar att den föreslagna lösningen kan minska tiden som behövs för att designa nätverkstopologier och tjänster. Fallen där detta är applicerbart, är när VNF:er närvarar i nätverk. Dessa är enklare att skapa, konfigurera, och ändra under tiden de exekverar, med den föreslagna metoden. Detta kräver också att nätverksoperatören är bekant med datamodelleringsspråket YANG. Tiden det tar att provisionera VNF:er, tills dess att de svarar till anslutningar, kan sänkas med hjälp av den föreslagna metoden. Den förslagna metoden erbjuder väsentligt begränsad funktionalitet jämfört med OpenStack, den fokuserar på att hantera VNF:er.

Denna avhandling utforskar den komplexa interaktionen mellan virtualiseringstekniker och prestanda för molnapplikationer. Genom att utvärdera hypervisor- och containerbaserade metoder skapar vi en teoretisk grund för att förstå rollen för virtualisering i modern molnbaserad miljö. Genom en metodisk förstudie och implementeringen av virtuella instanser samlar vi omfattande data om CPU-användning, nätverkstrafik, lagring och genomströmning, vilket avslöjar viktiga insikter. Resursanvändningen påverkas framför allt av hur databelastning ser ut, där resursintensiva uppgifter påverkar både hypervisor och containerinstanser. Studien visar att valet mellan hypervisor och containerteknik kan bero vissa användningsfall, vilket kräver ytterligare optimering. Att isolera tekniker på separata EC2- instanser ger bra kontroll men kräver löpande justeringar för varierande prestandamätningar. Slutsatserna hjälper till att förstå virtualiserings inverkan på molnapplikationer och betonar de avgörande rollerna för lagringshantering, nätverksdynamik och databelastning. Den här avhandlingen tar inte bara upp viktiga frågor, utan den lägger också grunden för framtida forskning som förutser förbättrad effektivitet och prestanda i virtualiserade molnmiljö. / This thesis explores the complex interaction between virtualization technologies and cloud application performance. By evaluating hypervisor and container-based approaches, we establish a theoretical foundation for understanding virtualization's role in modern cloud computing. Through a methodical pre-study and the implementation of virtual instances, we gather extensive data on CPU utilisation, network traffic, storage, and throughput to reveal key insights. Workloads notably impact resource usage, with resource-intensive tasks affecting both hypervisor and container instances. The study suggests that the choice between hypervisor and container technologies may depend on certain use cases, prompting further optimization. Isolating technologies on separate EC2 instances provides control but demands ongoing refinement for varied performance metrics. Conclusions contribute to understanding virtualization's impact on cloud applications, emphasising the critical roles of workload, network dynamics, and storage management. This thesis not only addresses key questions but also sets the stage for future explorations, promising enhanced performance and efficiency in virtualized cloud environments.

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper presents an approach to development of generic ground systems to be used for spacecraft testing and operations. This method makes use of a standard modeling method, which enables virtualization of spacecraft. By virtualizing spacecraft, development of generic systems that are applicable to different spacecraft becomes possible even if spacecraft themselves are not standardized. This is because systems can utilize (1) a standard database that can store information on any virtual spacecraft and (2) standard software tools that can be used for any virtual spacecraft. This paper explains the concept of virtualization of spacecraft, introduces the standard model used for virtualization of spacecraft, shows how to manipulate virtual spacecraft with software tools, and presents the core elements of generic ground systems.

System virtualization technology is widely used in computing nowadays. In embedded domain, it is used as a solution to resource sharing among independent applications. One of the areas is to apply virtualization technique to real-time embedded systems with timing constraints. Multi-level adaptive hierarchical scheduling (AdHierSched) framework is a virtualized real-time framework, which runs in the Linux operating system. Šis virtualized framework has ability to adapt the CPU partition sizes according to their need through monitoring their demand during run-time, which yields more appropriate processor assignment. However, the performance of the virtualized framework is still unknown when the budget borrowing mechanism is enabled. To this end, in this thesis, we explore a new direction for performing the adaptation of CPU partition. We design and implement a budget borrowing mechanism for dynamic adaptation of resource parameters in AdHierSched framework. Extensive simulations are performed in this thesis, which are used to study and compare di‚erent adaptation mechanisms with our approach. From the results of experiments, we conclude that when the framework works only with budget borrowing controller, the results are not as good as only running a budget controller in the AdHierSched framework. However, while running both of the controllers at the same time, the experiments results are good enough. We also analyze the overhead of the framework at the end of the evaluation. Finally, we conclude the thesis by presenting the possible future work.

Organizations are turning to private clouds due to concerns about security, privacy and administrative control. They are attracted by the flexibility and other advantages of cloud computing but are wary of breaking decades-old institutional practices and procedures. Private Clouds can help to alleviate these concerns by retaining security policies, in-organization ownership and providing increased accountability when compared with public services. This work investigates how it may be possible to develop an energy-aware private cloud system able to adapt workload allocation strategies so that overall energy consumption is reduced without loss of performance or dependability. Current literature focuses on consolidation as a method for improving the energy-efficiency of cloud systems, but if consolidation is undesirable due to the performance penalties, dependability or latency then another approach is required. Given a private cloud in which the machines are constant, with no machines being powered down in response to changing workloads, and a set of virtual machines to run, each with different characteristics and profiles, it is possible to mix the virtual machine placement to reduce energy consumption or improve performance of the VMs. Through a series of experiments this work demonstrates that workload mixes can have an effect on energy consumption and the performance of applications running inside virtual machines. These experiments took the form of measuring the performance and energy usage of applications running inside virtual machines. The arrangement of these virtual machines on their hosts was varied to determine the effect of different workload mixes. The insights from these experiments have been used to create a proof-of- concept custom VM Allocator system for the OpenStack private cloud computing platform. Using CloudMonitor, a lightweight monitoring application to gather data on system performance and energy consumption, the implementation uses a holistic view of the private cloud state to inform workload placement decisions.