Server virtualization is currently a field of IT which is undergoing a rapid development. Introducing an even spread of performance on server farms which results in a good TCO (total cost of ownership), virtualization has already got the full attention from industry, resulting in massive participation and huge acquisitions. With server virtualization the size of server farms can be reduced dramatically, resulting in a lower total cost of ownership and (by using techniques like Linux-HA in virtual environments) increased availability. Even with an overhead of 10-20% on the layer of virtualization it is still very interesting since the load on a server farm can be spread evenly (which is not only a main target in server virtualization but also in distributed systems in general).
This work will give an insight on the current developments in the field of server virtualization and the various techniques involved in it as well as a short historical overview about when the first types of virtualization were introduced (and why they failed, since according to A. Tanenbaum the current hardware is not made to be virtualized). The findings will mostly be supported by examples of current virtual environments (especially the XEN project).
The paper will first introduce the different ways of virtualizing a system and in how far hardware can or can not support this. The second part will introduce the current software for virtualizing a server and giving users their own separated environment, starting from early approaches like BSD jails to the Linux V-Server and XEN Project. The last chapter will cover the use of server virtualization in high-availability environments. With the use of n physical machines and m virtualized systems on each machine, an environment of (n * m) / x can be created, where x is the level of redundancy (e.g. x = 2 for mirroring). Most interesting is how virtual environments can be moved from one physical machine to another one without switching it off. The summary will give some insight on the current use of virtual environments and in how far they provide advantages over solutions like Mosix, Application-basic virtualization and the grid. It will also give an outlook on further developments especially in the field of hardware support for virtualization.
Inhaltsverzeichnis (Table of Contents)
- Abstract
- Table of contents
- Introduction
- Why virtualization?
- Brief history of virtual environments & virtualization.
- Server virtualization techniques & terminology.
- Server virtualization fundamentals.
- Hypervisor/Virtual machine monitor.
- Hardware support for virtualization
- Server virtualization software and techniques.
- VMWare GSX/ESX Server.
- Microsoft Virtual PC.
- XEN.
- Sharing drivers/hardware amongst virtual environments
- Virtuozzo / OpenVZ.
- Linux VServer Project.
- Performance and feature comparison
- Case study: Virtualization for highly available systems
- Motivation
- Definition and requirements of a highly available system
- Case study.
- Cost comparison.
- XEN installation and caveats.
- Redundant Disk Arrays.
- Highly available file server
- Alive and kicking with heartbeat.
- Deployment of the guest OS
- The role of Virtual Machine Migration (VMM)
- Results
- Bringing the worst case together.
- Limitations and problems in terms of practicability.
- Limitations in terms of availability
- Improvements to gain real high-availability.
- Summary and Outlook.
- Will Virtualization begin a new era in high availability computing?
- Natively supported operating systems ...
- Limitation of virtualization: Licensing aspects
- Problems of virtual environments.
- Virtualization rootkits... a new threat?
- Table of abbreviations
- Bibliography
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This work explores the concept of server virtualization, examining its current state, historical development, and potential applications in high-availability computing. The primary objective is to provide insights into the various virtualization techniques, their advantages and disadvantages, and to assess the feasibility of combining server virtualization with high availability solutions.
- Server Virtualization: Exploring different virtualization types and techniques, including full system emulation, paravirtualization, and native virtualization.
- Hardware Support: Analyzing the role of hardware in virtualization, including its limitations and potential for future developments.
- Software Solutions: Examining popular virtualization software packages, such as VMWare GSX/ESX Server, Microsoft Virtual PC, XEN, Virtuozzo/OpenVZ, and Linux VServer Project.
- High Availability: Investigating the use of server virtualization in creating highly available systems, focusing on redundancy, failover mechanisms, and virtual machine migration.
- Security and Isolation: Addressing security considerations in virtual environments, particularly in relation to isolation and the potential for new threats such as virtualization rootkits.
Zusammenfassung der Kapitel (Chapter Summaries)
The work begins with an introduction to server virtualization, highlighting its advantages and the motivation behind its increasing adoption. The chapter discusses the history of virtualization, tracing its origins from early time-sharing concepts to modern virtualization software. It then delves into the various techniques employed for virtualizing servers, outlining the functions, strengths, and weaknesses of each method.
Chapter 2 explores the fundamentals of server virtualization, focusing on the role of hypervisors and the hardware support necessary for successful virtualization. It addresses the limitations imposed by current hardware and discusses potential future developments in this area.
Chapter 3 provides a comprehensive overview of popular server virtualization software packages, including commercial solutions such as VMWare GSX/ESX Server and Microsoft Virtual PC, and open-source projects like XEN, Virtuozzo/OpenVZ, and Linux VServer Project. It compares these solutions based on their performance, features, and virtualization types.
Chapter 4 delves into the use of server virtualization in the context of high-availability computing. It examines the motivations behind integrating virtualization and high availability, outlining the requirements for creating a robust and redundant system. This chapter presents a case study demonstrating the implementation of XEN for high-availability, exploring various aspects such as cost comparison, XEN installation, and the role of virtual machine migration.
Schlüsselwörter (Keywords)
The key terms and concepts explored in this work include server virtualization, hypervisor, full system emulation, paravirtualization, native virtualization, hardware support, software solutions, VMWare GSX/ESX Server, Microsoft Virtual PC, XEN, Virtuozzo/OpenVZ, Linux VServer Project, high availability, redundancy, failover, virtual machine migration, security, isolation, virtualization rootkits.
- Quote paper
- Stephan Winter (Author), 2007, Concept for system virtualization in the field of high availability computing, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/71330
