Virtualization

9 Key excerpts on "Virtualization"

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  eBook - PDF

  Grid Application Systems Design

  • April J. Wells(Author)
  • 2007(Publication Date)
  • CRC Press

    (Publisher)

  169 Chapter 8 Virtualization Computer Science is no more about computers than astronomy is about telescopes. —Edsger W. Dijkstra Virtualization, loosely translated, means an abstraction of computer resources. It is a technique used for hiding the physical characteristics of computing resources or a way of making multiple physical resources (storage devices or servers) appear as a single logical resource. Virtualization, however, is not necessarily a Grid-related concept. Far from it, in fact. Virtualization has been used extensively since at least the early 1960s and has been applied to many different aspects of computing. It has been used in entire computer systems component and components. Virtualization technologies are usually employed through the hiding of tech-nical details of the underlying components through encapsulation that creates an external interface to the underlying implementation. Recent developments in Grid technologies have renewed development in these technologies and refocused atten-tion on the concept. Platform Virtualization is used to simulate virtual machines. Resource virtual-ization is used to simulate combined, fragmented, and simplified resources. In Grid-related information technology, Virtualization can take on several meanings, depending on what is being virtualized. If computer hardware is what we are visualizing, then Virtualization implies that we will use software to emulate either the hardware or an entire computer system environment other than the one on which the software is actually running. This Virtualization of hardware is often referred to as a virtual machine . The term “virtual 170 n Grid Applications Systems Design machine” has been connected directly with Sun Microsystems’ Java programming language. That context defines an abstracted or conceptual machine rather than a real machine.

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  eBook - ePub

  Cloud Computing Simplified

  Explore Application of Cloud, Cloud Deployment Models, Service Models and Mobile Cloud Computing (English Edition)

  • Surbhi Rastogi(Author)
  • 2021(Publication Date)
  • BPB Publications

    (Publisher)

  As we know, cloud computing is the act of providing the access of resources and storage to multiple organizations. Cloud vendors allocate resources, storage, and other services to organizations. Since they have a sufficient amount of physical hardware resources, software applications, network resources, and storage, they provide these resources on rent to the customers. However, if every customer demands for new resources, then it would be cumbersome to have so many physical instances of resources and it might overload the storage capacity of the cloud providers. Here, the concept of Virtualization comes into existence. With Virtualization, cloud vendors can create virtual copies of their infrastructures and servers and assign those copies of resources to the users or organizations.

  Virtualization refers to the creation of a virtual version of hardware or software resources, storage devices, or network devices. This technique is helpful as it provides the users with multiple machines at the same time. Multiple OS and applications can run on the same machine. With Virtualization, a single physical instance of a resource or application gets divided into multiple logical partitions and can be shared among multiple customers. Customers do not have any idea about logical partitions. To them, I it seems that they solely access the applications or resources. A physical resource is assigned a logical name for its address. When a user demands for a resource, a pointer is assigned to that physical resource.

  Virtualization is a technology in cloud computing that provides the facility of sharing a single physical instance of a resource, server, or operating system among multiple users or organizations. It creates a virtual environment where virtual copies of all infrastructures including servers, networks, hardware, software, and operating systems is created and used by the users accessing the cloud computing services. Virtualization is very beneficial as it helps in reducing workload which results in increased utilization and flexibility of hardware. This technique helps companies in implementing cloud computing.

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  Cloud Computing

  An Introduction

  • Rajiv Chopra(Author)
  • 2017(Publication Date)
  • Mercury Learning and Information

    (Publisher)

  Virtualization TECHNOLOGY IN THE CLOUD 3 C H A P T E R 3.1 INTRODUCTION V irtualization can be defined as the abstraction of four computing re- sources—storage, processing power, memory, and network (I/O). Conceptually, it is similar to emulation where a system pretends to be another system, whereas Virtualization is a system pretending to be two or more of the same system type. Today Virtualization is better than parallelism. It has helped to evolve the cloud data center techniques and tools. These tech- nologies manage the dynamic data center infrastructure as well. Virtualization partitions the physical resources of the underlying physical server into multiple virtual machines with different workloads. The Virtualization layer schedules and allocates the physical resources and makes each virtual machine think that it completely owns all of the physical resources of the underlying hardware. This technology is very useful for cloud computing because it improves re- source utilization by multiplexing many virtual machines on one physical host. Thus, these machines can be scaled up or down on-demand, and thus, better management techniques are required. The complex applications of today cannot be feasibly run on the existing physical hardware alone. It is, however, possible to implement, test, and run large applications with the help of this Virtualization technology. Virtual technol- ogy creates virtual versions of hardware, operating systems (OSs), networking devices, and storage devices. Therefore, many guests OSs can now be run on a single physical machine called a host machine and multiple guest applications run on a single server called a host server. Additionally, this technology allows 98 • CLOUD COMPUTING a single physical resource to work as multiple virtual resources and multiple physical resources as a single virtual resource.

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  Hardware and Software Support for Virtualization

  • Edouard Bugnion, Jason Nieh, Dan Tsafrir(Authors)
  • 2022(Publication Date)
  • Springer

    (Publisher)

  1.1 Virtualization . . Virtualization is the application of the layering principle through enforced modularity, whereby the exposed virtual resource is identical to the underlying physical resource being virtualized. ¹N.B.: the terms hypervisor and virtual machine monitor have been used interchangeably in the literature. Here, we prefer the term hypervisor when describing an entire system and the term VMM when describing the subsystem that virtualizes the CPU and memory, or in its historical formal context in Chapter 2. 2 1. DEFINITIONS is definition is grounded in two fundamental principles of computer systems. First, layering is the presentation of a single abstraction, realized by adding a level of indirection, when (i) the indirection relies on a single lower layer and (ii) uses a well-defined namespace to expose the abstraction. Second, enforced modularity additionally guarantees that the clients of the layer cannot bypass the abstraction layer, for example to access the physical resource directly or have visibility into the usage of the underlying physical namespace. Virtualization is therefore nothing more than an instance of layering for which the exposed abstraction is equivalent to the underlying physical resource. is combination of indirection, enforced modularity, and compatibility is a particularly powerful way to both reduce the complexity of computer systems and simplify operations. Let’s take the classic example of RAID [48], in which a redundant array of inexpensive disk is aggre- gated to form a single, virtual disk. Because the interface is compatible (it is a block device for both the virtual and physical disks), a filesystem can be deployed identically, whether the RAID layer is present or not.

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  eBook - PDF

  Essentials of Cloud Computing

  • K. Chandrasekaran(Author)
  • 2014(Publication Date)
  • Chapman and Hall/CRC

    (Publisher)

  Application Application Application Application Application Application Application Application Operating system (Linux) Virtual machine Virtual infrastructure Physical shared infrastructure Virtual machine Operating system (Windows) VProcessor VProcessor VMemory VMemory VStorage VStorage VNetwork VNetwork Processor Memory Storage Network FIGURE 7.2 After Virtualization. 164 Essentials of Cloud Computing discussed in the later part of this chapter. Industries adopt Virtualization in their organization because of the following benefits: • Better resource utilization • Increases ROI • Dynamic data center • Supports green IT • Eases administration • Improves disaster recovery While Virtualization offers many benefits, it also has some drawbacks: • Single point of failure • Demands high-end and powerful infrastructure • May lead to lower performance • Requires specialized skill set This chapter focuses on the different Virtualization opportunities, dif-ferent approaches to Virtualization, role of the hypervisors in virtual-ization, attacks that target the hypervisors, and Virtualization for cloud computing. 7.2 Virtualization Opportunities Virtualization is the process of abstracting the physical resources to the pool of virtual resources that can be given to any virtual machines (VMs). The different resources like memory, processors, storage, and network can be vir-tualized using proper Virtualization technologies. In this section, we shall discuss some of the resources that can be virtualized. 7.2.1 Processor Virtualization Processor Virtualization allows the VMs to share the virtual processors that are abstracted from the physical processors available at the underlying infra-structure. The Virtualization layer abstracts the physical processor to the pool of virtual processors that is shared by the VMs. The Virtualization layer will be normally any hypervisors. Processor Virtualization from a single hardware is illustrated in Figure 7.3.

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  eBook - PDF

  Virtualization with Xen(tm): Including XenEnterprise, XenServer, and XenExpress

  • David E. Williams(Author)
  • 2007(Publication Date)
  • Syngress

    (Publisher)

  This chapter will introduce you to the core concepts of server, storage, and net- work Virtualization as a foundation for learning more about Xen. This chapter will also illustrate the potential benefits of Virtualization to any organization. What Is Virtualization? So what exactly is Virtualization? Today, that question has many answers. Different manufacturers and independent software vendors coined that phrase to categorize their products as tools to help companies establish virtualized infrastructures. Those claims are not false, as long as their products accomplish some of the following key points (which are the objectives of any Virtualization technology) • Add a layer of abstraction between the applications and the hardware • Enable a reduction in costs and complexity • Provide the isolation of computer resources for improved reliability and security • Improve service levels and the quality of service An Introduction to Virtualization • Chapter 1 3 • Better align IT processes with business goals • Eliminate redundancy in, and maximize the utilization of, IT infrastructures While the most common form of Virtualization is focused on server hardware platforms, these goals and supporting technologies have also found their way into other critical~and expensive~components of modern data centers, including storage and network infrastructures. But to answer the question What is Virtualization? we must first discuss the his- tory and origins of Virtualization, as clearly as we understand it. The History of Virtualization In its conceived form, Virtualization was better known in the 1960s as time sharing. Christopher Strachey, the first Professor of Computation at Oxford University and leader of the Programming Research Group, brought this term to life in his paper Time Sharino~ in Large Fast Computers. Strachey, who was a staunch advocate of main- taining a balance between practical and theoretical work in computing, was referring to what he called multiprogramming.

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  eBook - ePub

  Mobile Cloud Computing

  Foundations and Service Models

  • Dijiang Huang, Huijun Wu(Authors)
  • 2017(Publication Date)
  • Morgan Kaufmann

    (Publisher)

  It does not provide a VM, but a virtual environment that has its own CPU, memory, block I/O, network, etc. It makes use of the Linux kernel's cgroups functionality, which provides isolated namespace(s) to run isolated applications. One advantage of containers is that they do not require a full-fledged guest OS like VMs. For container's details, see Section 2.3. Linux-VServer [6]. Linux-VServer is an OS level Virtualization solution. It's a soft partitioning concept technology based on security contexts. It basically creates Virtual Private Servers (VPS) that run simultaneously on a single physical server by sharing hardware resources. Each VPS has its own database account and root password so that it's isolated from other virtual servers. Virtualization for cloud computing As presented in previous classifications of Virtualization approaches, there are several different breeds of Virtualization, though all of them share one thing in common – the end result is a virtualized simulation of a device or resource. In other words, Virtualization is generally accomplished by dividing a single piece of hardware into two or more “segments.” Each segment operates as its own independent environment. In Cloud Computing, the cloud determines how virtualized resources are allocated, delivered, and presented. Cloud computing is built on Virtualization technologies. The relation between cloud and Virtualization can be viewed as follows: Virtualization can exist without the cloud, but cloud computing cannot exist without Virtualization. Virtualization is not necessary to create a cloud environment, but it enables rapid scaling of resources in a way that nonvirtualized environments find hard to achieve. As shown in Fig. 2.9, it presents the representation between the Virtualization of a computer and the Virtualization of cloud resources

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  Large Scale and Big Data

  Processing and Management

  • Sherif Sakr, Mohamed Gaber, Sherif Sakr, Mohamed Gaber(Authors)
  • 2014(Publication Date)
  • Auerbach Publications

    (Publisher)

  524 16.8.4 A Taxonomy of Virtualization Suites ............................................. 524 496 Large Scale and Big Data Virtualization is at the core of cloud computing. It lies on top of the cloud infrastruc-ture, whereby virtual resources (e.g., virtual CPUs, memories, disks, networks) are con-structed from the underlying physical resources and act as proxies to them. As is the case with the idea of cloud computing, which was first introduced in the 1960s [1], virtual-ization can be traced back to the 1970s [55]. Forty years ago, the mainframe computer systems were extremely large and expensive. To address expanding user needs and costly machine ownerships, the IBM 370 architecture, announced in 1970, offered complete virtual machines (virtual hardware images) to different programs running at the same computer hardware. Over time, computer hardware became less expensive and users started migrating to low-priced desktop machines. This drove the adoption of the virtu-alization technology to fade for a while. Today, Virtualization is enjoying a resurgence in popularity with a number of research projects and commercial systems providing virtu-alization solutions for commodity PCs, servers, and the cloud. In this chapter, we present various ingredients of the Virtualization technology and the crucial role it plays in enabling the cloud computing paradigm. First, we identify major reasons for why Virtualization is becoming important, especially for the cloud. Second, we indicate how multiple software images can run side by side on physical resources while attaining security, resource and failure isolations. Prior to delving into more details about Virtualization, we present a brief background requi-site for understanding how physical resources can be virtualized. In particular, we learn how system complexity can be managed in terms of levels of abstractions and well-defined interfaces.

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  eBook - PDF

  Advanced Server Virtualization

  VMware and Microsoft Platforms in the Virtual Data Center

  • David Marshall, Wade A. Reynolds, Dave McCrory(Authors)
  • 2006(Publication Date)
  • Auerbach Publications

    (Publisher)

  Think for a moment, if the server in question does not have any anti-virus software or if the patch level is not up to date, what would this do to the call center’s network? Within minutes of the machine being powered on, the entire network could become compromised. Once again, by using virtual-ization and its virtual network cards and virtual network, the machine can be safely powered on and isolated from the production network and still maintain network connectivity between multiple virtual machine environments or the outside world. If the virtual machine crashes or causes a problem, only the vir-tual machine and those virtual machines connected to it in the isolated network are affected. The physical host server and the other virtual machines on that host server are spared, as is the production network. Finally, Virtualization creates another tool for the technical support specialist. While troubleshooting a product for a customer, if the technical support spe-cialist discovers the problem is a bug within the company’s software, they would usually just log the bug within some bug tracking software for the development team or the QA team. Now, along with the text description of the bug, the tech-nical support specialist can attach a copy of the customer’s virtual machine that exhibits the defect. This helps the development group to quickly see the defect and create a hot fix or a patch to resolve the problem. Again, the time to resolve the problem for the customer is greatly diminished. Software Training and E-Learning Systems As applications and training environments become more complicated, it is be-coming commonplace for instructors to spend more of their time setting up the classroom rather than actually teaching the course. The alternative is forcing the instructor to come in on weekends to setup, deploy, and properly test the classroom environment, or to hire a separate position to fill this gap.

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