第 1 章 Red Hat虚​​​​​​​拟​​​​​​​化​​​​​​​系​​​​​​​统​​​​​​​体​​​​​​​系​​​​​​​结​​​​​​​构​​​​​​​

红​​​​​​​帽​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​系​​​​​​​统​​​​​​​是​​​​​​​多​​​​​​​层​​​​​​​的​​​​​​​，它​​​​​​​由​​​​​​​专​​​​​​​用​​​​​​​的​​​​​​​红​​​​​​​帽​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​组​​​​​​​件​​​​​​​驱​​​​​​​动​​​​​​​。​​​​​​​红​​​​​​​帽​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​系​​​​​​​统​​​​​​​可​​​​​​​以​​​​​​​支​​​​​​​持​​​​​​​多​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​。​​​​​​​每​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​都​​​​​​​运​​​​​​​行​​​​​​​在​​​​​​​自​​​​​​​己​​​​​​​的​​​​​​​域​​​​​​​里​​​​​​​。​​​​​​​红​​​​​​​帽​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​系​​​​​​​统​​​​​​​在​​​​​​​虚​​​​​​​拟​​​​​​​机​​​​​​​内​​​​​​​调​​​​​​​度​​​​​​​虚​​​​​​​拟​​​​​​​ CPU 来​​​​​​​最​​​​​​​好​​​​​​​地​​​​​​​利​​​​​​​用​​​​​​​可​​​​​​​用​​​​​​​的​​​​​​​物​​​​​​​理​​​​​​​ CPU。​​​​​​​每​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​都​​​​​​​处​​​​​​​理​​​​​​​自​​​​​​​己​​​​​​​的​​​​​​​应​​​​​​​用​​​​​​​程​​​​​​​序​​​​​​​。​​​​​​​这​​​​​​​些​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​也​​​​​​​相​​​​​​​应​​​​​​​地​​​​​​​调​​​​​​​度​​​​​​​每​​​​​​​个​​​​​​​应​​​​​​​用​​​​​​​程​​​​​​​序​​​​​​​。​​​​​​​

你​​​​​​​可​​​​​​​以​​​​​​​以​​​​​​​两​​​​​​​种​​​​​​​方​​​​​​​式​​​​​​​来​​​​​​​部​​​​​​​署​​​​​​​红​​​​​​​帽​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​系​​​​​​​统​​​​​​​：完​​​​​​​全​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​（full virtualization）或​​​​​​​半​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​（paravirtualization）。​​​​​​​完​​​​​​​全​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​提​​​​​​​供​​​​​​​底​​​​​​​层​​​​​​​物​​​​​​​理​​​​​​​系​​​​​​​统​​​​​​​的​​​​​​​全​​​​​​​部​​​​​​​抽​​​​​​​象​​​​​​​化​​​​​​​，且​​​​​​​创​​​​​​​建​​​​​​​一​​​​​​​个​​​​​​​新​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​系​​​​​​​统​​​​​​​，客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​可​​​​​​​以​​​​​​​在​​​​​​​里​​​​​​​面​​​​​​​运​​​​​​​行​​​​​​​。​​​​​​​不​​​​​​​需​​​​​​​要​​​​​​​对​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​或​​​​​​​者​​​​​​​应​​​​​​​用​​​​​​​程​​​​​​​序​​​​​​​进​​​​​​​行​​​​​​​修​​​​​​​改​​​​​​​（客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​或​​​​​​​者​​​​​​​应​​​​​​​用​​​​​​​程​​​​​​​序​​​​​​​象​​​​​​​往​​​​​​​常​​​​​​​一​​​​​​​样​​​​​​​运​​​​​​​行​​​​​​​，意​​​​​​​识​​​​​​​不​​​​​​​到​​​​​​​虚​​​​​​​拟​​​​​​​环​​​​​​​境​​​​​​​的​​​​​​​存​​​​​​​在​​​​​​​）。​​​​​​​半​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​需​​​​​​​要​​​​​​​对​​​​​​​运​​​​​​​行​​​​​​​在​​​​​​​虚​​​​​​​拟​​​​​​​机​​​​​​​器​​​​​​​上​​​​​​​的​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​进​​​​​​​行​​​​​​​修​​​​​​​改​​​​​​​（这​​​​​​​些​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​会​​​​​​​意​​​​​​​识​​​​​​​到​​​​​​​它​​​​​​​们​​​​​​​运​​​​​​​行​​​​​​​在​​​​​​​虚​​​​​​​拟​​​​​​​环​​​​​​​境​​​​​​​里​​​​​​​）并​​​​​​​提​​​​​​​供​​​​​​​相​​​​​​​近​​​​​​​的​​​​​​​性​​​​​​​能​​​​​​​。​​​​​​​完​​​​​​​全​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​和​​​​​​​半​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​都​​​​​​​可​​​​​​​以​​​​​​​部​​​​​​​署​​​​​​​在​​​​​​​你​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​构​​​​​​​架​​​​​​​里​​​​​​​。​​​​​​​

第​​​​​​​一​​​​​​​个​​​​​​​域​​​​​​​，称​​​​​​​为​​​​​​​ domain0 (dom0)，在​​​​​​​你​​​​​​​引​​​​​​​导​​​​​​​系​​​​​​​统​​​​​​​时​​​​​​​自​​​​​​​动​​​​​​​创​​​​​​​建​​​​​​​。​​​​​​​Domain0 是​​​​​​​专​​​​​​​用​​​​​​​的​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​，它​​​​​​​拥​​​​​​​有​​​​​​​创​​​​​​​建​​​​​​​新​​​​​​​域​​​​​​​并​​​​​​​管​​​​​​​理​​​​​​​它​​​​​​​们​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​设​​​​​​​备​​​​​​​的​​​​​​​管​​​​​​​理​​​​​​​能​​​​​​​力​​​​​​​。​​​​​​​Domain0 处​​​​​​​理​​​​​​​物​​​​​​​理​​​​​​​硬​​​​​​​件​​​​​​​，如​​​​​​​网​​​​​​​卡​​​​​​​和​​​​​​​硬​​​​​​​盘​​​​​​​控​​​​​​​制​​​​​​​器​​​​​​​。​​​​​​​Domain0 也​​​​​​​处​​​​​​​理​​​​​​​管​​​​​​​理​​​​​​​性​​​​​​​的​​​​​​​任​​​​​​​务​​​​​​​，如​​​​​​​暂​​​​​​​停​​​​​​​、​​​​​​​恢​​​​​​​复​​​​​​​执​​​​​​​行​​​​​​​或​​​​​​​移​​​​​​​植​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​域​​​​​​​到​​​​​​​其​​​​​​​他​​​​​​​虚​​​​​​​拟​​​​​​​机​​​​​​​里​​​​​​​。​​​​​​​

The hypervisor (Red Hat's Virtual Machine Monitor) is a virtualization platform that allows multiple operating systems to run on a single host simultaneously within a full virtualization environment. A guest is an operating system (OS) that runs on a virtual machine in addition to the host or main OS.

With Red Hat Virtualization, each guests memory comes from a slice of the host's physical memory. For paravirtual guests, you can set both the initial memory and the maximum size of the virtual machine. You can add (or remove) physical memory to the virtual machine at runtime without exceeding the maximum size you specify. This process is called ballooning.

你​​​​​​​可​​​​​​​以​​​​​​​用​​​​​​​许​​​​​​​多​​​​​​​虚​​​​​​​拟​​​​​​​ cpu（称​​​​​​​为​​​​​​​ vcpu）来​​​​​​​配​​​​​​​置​​​​​​​每​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​。​​​​​​​虚​​​​​​​拟​​​​​​​机​​​​​​​管​​​​​​​理​​​​​​​程​​​​​​​序​​​​​​​按​​​​​​​照​​​​​​​物​​​​​​​理​​​​​​​ CPU 的​​​​​​​负​​​​​​​载​​​​​​​来​​​​​​​调​​​​​​​度​​​​​​​这​​​​​​​些​​​​​​​ vcpu。​​​​​​​

你​​​​​​​可​​​​​​​以​​​​​​​授​​​​​​​予​​​​​​​某​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​任​​​​​​​何​​​​​​​数​​​​​​​量​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​磁​​​​​​​盘​​​​​​​（virtual disks）。​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​把​​​​​​​这​​​​​​​些​​​​​​​磁​​​​​​​盘​​​​​​​视​​​​​​​为​​​​​​​硬​​​​​​​盘​​​​​​​或​​​​​​​（对​​​​​​​于​​​​​​​完​​​​​​​全​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​而​​​​​​​言​​​​​​​）CD-ROM 设​​​​​​​备​​​​​​​。​​​​​​​每​​​​​​​个​​​​​​​虚​​​​​​​拟​​​​​​​磁​​​​​​​盘​​​​​​​都​​​​​​​以​​​​​​​块​​​​​​​设​​​​​​​备​​​​​​​或​​​​​​​主​​​​​​​机​​​​​​​上​​​​​​​的​​​​​​​常​​​​​​​规​​​​​​​文​​​​​​​件​​​​​​​的​​​​​​​方​​​​​​​式​​​​​​​供​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​使​​​​​​​用​​​​​​​。​​​​​​​主​​​​​​​机​​​​​​​上​​​​​​​的​​​​​​​设​​​​​​​备​​​​​​​包​​​​​​​含​​​​​​​了​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​的​​​​​​​完​​​​​​​整​​​​​​​的​​​​​​​磁​​​​​​​盘​​​​​​​映​​​​​​​像​​​​​​​，通​​​​​​​常​​​​​​​也​​​​​​​包​​​​​​​括​​​​​​​了​​​​​​​分​​​​​​​区​​​​​​​表​​​​​​​、​​​​​​​多​​​​​​​重​​​​​​​分​​​​​​​区​​​​​​​和​​​​​​​可​​​​​​​能​​​​​​​的​​​​​​​ LVM 物​​​​​​​理​​​​​​​卷​​​​​​​。​​​​​​​

虚​​​​​​​拟​​​​​​​网​​​​​​​络​​​​​​​接​​​​​​​口​​​​​​​（Virtual networking interface）运​​​​​​​行​​​​​​​在​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​上​​​​​​​。​​​​​​​象​​​​​​​虚​​​​​​​拟​​​​​​​以​​​​​​​太​​​​​​​网​​​​​​​卡​​​​​​​（VNIC）一​​​​​​​样​​​​​​​，其​​​​​​​他​​​​​​​接​​​​​​​口​​​​​​​可​​​​​​​以​​​​​​​运​​​​​​​行​​​​​​​在​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​上​​​​​​​。​​​​​​​这​​​​​​​些​​​​​​​网​​​​​​​络​​​​​​​接​​​​​​​口​​​​​​​用​​​​​​​永​​​​​​​久​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​ MAC 地​​​​​​​址​​​​​​​配​​​​​​​置​​​​​​​。​​​​​​​新​​​​​​​安​​​​​​​装​​​​​​​的​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​会​​​​​​​缺​​​​​​​省​​​​​​​安​​​​​​​装​​​​​​​ VNIC，它​​​​​​​的​​​​​​​ MAC 地​​​​​​​址​​​​​​​从​​​​​​​一​​​​​​​个​​​​​​​有​​​​​​​着​​​​​​​一​​​​​​​千​​​​​​​六​​​​​​​百​​​​​​​万​​​​​​​地​​​​​​​址​​​​​​​的​​​​​​​储​​​​​​​备​​​​​​​池​​​​​​​里​​​​​​​随​​​​​​​机​​​​​​​选​​​​​​​取​​​​​​​，所​​​​​​​以​​​​​​​两​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​接​​​​​​​受​​​​​​​相​​​​​​​同​​​​​​​ MAC 地​​​​​​​址​​​​​​​是​​​​​​​不​​​​​​​太​​​​​​​可​​​​​​​能​​​​​​​的​​​​​​​。​​​​​​​有​​​​​​​着​​​​​​​大​​​​​​​量​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​的​​​​​​​复​​​​​​​杂​​​​​​​站​​​​​​​点​​​​​​​可​​​​​​​以​​​​​​​手​​​​​​​工​​​​​​​分​​​​​​​配​​​​​​​ MAC 地​​​​​​​址​​​​​​​来​​​​​​​确​​​​​​​保​​​​​​​在​​​​​​​网​​​​​​​络​​​​​​​里​​​​​​​的​​​​​​​唯​​​​​​​一​​​​​​​性​​​​​​​。​​​​​​​

每​​​​​​​个​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​都​​​​​​​有​​​​​​​一​​​​​​​个​​​​​​​连​​​​​​​接​​​​​​​至​​​​​​​主​​​​​​​机​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​文​​​​​​​本​​​​​​​控​​​​​​​制​​​​​​​台​​​​​​​（text console）。​​​​​​​你​​​​​​​可​​​​​​​以​​​​​​​把​​​​​​​客​​​​​​​户​​​​​​​登​​​​​​​录​​​​​​​和​​​​​​​控​​​​​​​制​​​​​​​台​​​​​​​输​​​​​​​出​​​​​​​重​​​​​​​定​​​​​​​向​​​​​​​到​​​​​​​这​​​​​​​个​​​​​​​文​​​​​​​本​​​​​​​控​​​​​​​制​​​​​​​台​​​​​​​。​​​​​​​

你​​​​​​​可​​​​​​​以​​​​​​​配​​​​​​​置​​​​​​​任​​​​​​​何​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​来​​​​​​​使​​​​​​​用​​​​​​​虚​​​​​​​拟​​​​​​​图​​​​​​​形​​​​​​​控​​​​​​​制​​​​​​​台​​​​​​​（graphical console），这​​​​​​​对​​​​​​​应​​​​​​​于​​​​​​​物​​​​​​​理​​​​​​​主​​​​​​​机​​​​​​​上​​​​​​​的​​​​​​​普​​​​​​​通​​​​​​​的​​​​​​​显​​​​​​​示​​​​​​​控​​​​​​​制​​​​​​​台​​​​​​​。​​​​​​​对​​​​​​​于​​​​​​​完​​​​​​​全​​​​​​​和​​​​​​​半​​​​​​​虚​​​​​​​拟​​​​​​​化​​​​​​​客​​​​​​​户​​​​​​​机​​​​​​​你​​​​​​​都​​​​​​​可​​​​​​​以​​​​​​​使​​​​​​​用​​​​​​​它​​​​​​​。​​​​​​​它​​​​​​​具​​​​​​​有​​​​​​​标​​​​​​​准​​​​​​​的​​​​​​​图​​​​​​​形​​​​​​​适​​​​​​​配​​​​​​​器​​​​​​​的​​​​​​​特​​​​​​​征​​​​​​​，如​​​​​​​引​​​​​​​导​​​​​​​信​​​​​​​息​​​​​​​、​​​​​​​图​​​​​​​形​​​​​​​化​​​​​​​引​​​​​​​导​​​​​​​、​​​​​​​多​​​​​​​个​​​​​​​虚​​​​​​​拟​​​​​​​终​​​​​​​端​​​​​​​以​​​​​​​及​​​​​​​ X 窗​​​​​​​口​​​​​​​系​​​​​​​统​​​​​​​。​​​​​​​你​​​​​​​也​​​​​​​可​​​​​​​以​​​​​​​使​​​​​​​用​​​​​​​图​​​​​​​形​​​​​​​化​​​​​​​键​​​​​​​盘​​​​​​​来​​​​​​​配​​​​​​​置​​​​​​​虚​​​​​​​拟​​​​​​​键​​​​​​​盘​​​​​​​和​​​​​​​鼠​​​​​​​标​​​​​​​。​​​​​​​

Guests can be identified in any of three identities: domain name (domain-name), identity (domain-id), or UUID. The domain-name is a text string that corresponds to a guest configuration file. The domain-name is used to launch the guests, and when the guest runs the same name is used to identify and control it. The domain-id is a unique, non-persistent number that gets assigned to an active domain and is used to identify and control it. The UUID is a persistent, unique identifier that is controlled from the guest's configuration file and ensures that the guest is identified over time by system management tools. It is visible to the guest when it runs. A new UUID is automatically assigned to each guest by the system tools when the guest first installs.