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Ubuntu服务器虚拟化解答

许多解答是现在可以得到的与虚拟化一起使用，但三他们是特别重要的：
? VMware
? Xen
? KVM (基于仁的虚拟机)

关于其他解答，您赢取了？由于他们可观的局限， t经常发现他们在数据中心，包括缺乏支持，操作系统一种有限的选择可以安装作为虚拟机和一项严厉表现惩罚，当使用他们时。为这些原因， I ？ll这里忽略他们，除了一个。如果您是对跑Ubuntu服务器感兴趣在a virtualized环境从桌面，您应该考虑安装VirtualBox，提供一种优秀虚拟化解答从一个图解桌面跑。

三重要技术， VMware是当前市场商情领头者。它提供一种商业解答virtualize许多不同的操作系统并且是可利用的超过10年的源远流长的虚拟化技术。最重要的VMware版本在数据中心是VMware ESX。您能使用ESX作为虚拟化主人，您将安装virtualized机器。 ESX集成虚拟机经理，是过程负责任对虚拟化的被做一个调整的Linux仁。

然而，如果您想要使用VMware ESX作为虚拟化平台，您？ll必须通过跑Ubuntu服务器做它，当a virtualized ？客人？操作系统在VMware环境之内。那里？当前s没有方式结合VMware ESX和Ubuntu服务器作为虚拟化？主人？平台(和不会有这样方法)。 VMware ESX是业主， welltuned有虚拟化作为其唯一的目的操作系统的环境。没有需要用任何东西替换它开放来源。

另一个重要球员在虚拟化领域是KVM，在Linux仁提供虚拟化支持。 KVM当前是用于Ubuntu服务器的缺省虚拟化技术。其他Linux供营商例如红色帽子也拥抱它作为他们的缺省。使用它，您？当然ll需要kvm.ko仁模块对Linux、有固定虚拟化支持的CPU和支持KVM虚拟化的仁。 (2.6.20仁是要做此的第一个Linux仁。)创造虚拟机与KVM，您？ll用途/dev/kvm接口和这种功能要求QEMU节目的一个修改过的版本。

QEMU最初被开发了作为打开来源仿效产品，但它未曾获得非常成功在数据中心方面。并且，即使它被开发使用作为虚拟化解答，它从未真正地做了它。 QEMU tools are still very useful, however, and QEMU tools and solutions are used in both KVM and Xen environments. Currently, most operating systems are supported on a KVM virtual host, provided that the operating system runs on the same processor architecture.

The other major player in the Linux virtualization market is Xen, which began as a research project at the University of Cambridge (see http://www.cl.cam.ac.uk/research/srg/netos/xen). Its core component is its hypervisor, the layer that makes it possible to create virtual machines and to handle instructions generated by those virtual machines. When used on a virtual machine host, the hypervisor replaces the normal Linux kernel, which is loaded only after the Xen hypervisor. Xen is currently one of the best virtualization platforms available on Linux, mainly because of its strong developer community, which includes hardware vendors such as Intel, HP, and AMD; and software vendors such as Novell and Red Hat. You can use Xen on Ubuntu Server as well, but the default virtualization stack is KVM.

Emulation means that software is used to simulate a hardware platform. An example is when you run a Sega Megadrive/Genesis emulator on your PC to run old games; the software runs all CPU instructions like the hardware does. The emulator behaves just like a software processor, a pure software virtual machine. You can run an i386 operating system on an i386-based CPU in two ways. First, you can use an i386 software emulator running on i386 (examples are Bochs and QEMU). In such a solution, the software behaves like a PC reproducing the complete hardware platform. Second, you can use a virtualization solution such as VMware Workstation. The virtualization solution does not provide a virtual CPU or any virtual base component of the basic PC hardware (IRQs controllers, hardware clock, and so on); it just puts the program to be virtualized on the real CPU and lets it execute the code. That solution needs complete hardware control, which is why it needs to run on privileged mode of the CPU and provides kernel modules for Linux to run in the kernel. Virtualization is not a next generation of emulation; it?s a different way of executing an operating system.

Source of Information : Apress Beginning Ubuntu LTS Server Administration