云计算入门PPT课件

1、云计算入门云计算入门Introduction to Cloud ComputingGESC1001Philippe Fournier-Philippe Fournier-VigerVigerProfessor School of Humanities and Social SFallFall 201 2019 91Lecture #3Lecture #32Based on Chapter 5A A computercomputer has threethree importantimportant resourcesresources:1) A processor processor (处理器

2、), , to perform calculations,3MemoryMemory, to store data Hard drive (硬盘驱动器) RAM (内存) 4For long-term storage, but accessing data is slowFor short-term storage, but accessing data is fastTo communicate with other computers local network Internet5Different types:6RJ45 Ethernet cableTV (电视）cableOptical

3、 fiber(光学纤维)WIFI(无线网络) Telephone cable (RJ11)They have different characteristics: bandwith (带宽), latency (延迟), cost (元）7RJ45 Ethernet cableTV (电视）cableOptical fiber(光学纤维)WIFI(无线网络) Telephone cable (RJ11)Each computer runs an operating operating systemsystem (操作系统） (e.g. e.g. Windows, Android, Linux,

4、 MacOS).Why do we need an operating system?Why do we need an operating system? 8Why do we need an operating system?Why do we need an operating system?1)to provide a user interface user interface ( (用户界面用户界面 ) ) to the user, 9This is a graphical user interfaceWhy do we need an operating system?Why do

5、 we need an operating system?1)to provide a user interface user interface ( (用户界面用户界面 ) ) to the user, 10This is a text-based user interfaceWhy do we need an operating system?Why do we need an operating system?2)to manage the applications manage the applications that are running on the computer.11Wh

6、y do we need an operating system?Why do we need an operating system?3)to manage the resourcesmanage the resources of the computer 12And also the devices such asKeyboard, mouse, screenMemoryProcessing resourceCommunication channelsResource management Resource management is complex complex for the clo

7、ud (for the cloud (云云) )。Why?Why?many computers, many users,many applications,many operating systems may be useddifferent kind of computers may be usedsome computers can fail (电脑故障)Resource management is discussed in detail in Chapter 6Chapter 6.13In a traditional data center data center (数据中心), a c

8、omputer may be accessed by many users many users at the same time.An operating system operating system (操作系统) is used for each computer in the data center. to manage and share resources with other computers, to protect applications and data from other applications, to make sure that performanceperfo

9、rmance is good for all usersfor all users.14SERVER15UsersSERVERBecauseBecause, , itit wouldwould bebe difficultdifficult to do to do system administration (系统管理), security (系统安全) how to protect data?, resource management (资源管理), accounting (who should pay? and how much (元) for using the cloud?)16Use

10、rsSERVERResource virtualization (Resource virtualization (资源虚拟化) is the topic of this chapter.It an approach to make it easy to manage the resources of many many computers in the cloud.Main ideaMain idea: each computer runs many virtual machines virtual machines (VM -虚拟机).17A virtual machine virtual

11、 machine (虚拟机): an application that simulates a real computer, including its processor, memory, and communication channels.A computercomputer can run many virtual machines at the same time.Each virtual machine virtual machine works like a real computer.A virtual machine virtual machine has: its own

12、operating system operating system (操作系统)(e.g. e.g. Windows), its own applicationsapplications.Note: Note: A more general definition more general definition of what is a virtual machine will be presented later.18At homeAt home, on a Windows computer, it is possible to use VirtualBoxVirtualBox or simi

13、lar applications or similar applications to create and run virtual machines (create and run virtual machines (虚拟机虚拟机) ).19Two Virtual machines (虚拟机虚拟机) )are runningA virtual machine virtual machine is also called an instance instance (实例) when we talk about cloud computing.The process of running vir

14、tual machines on a computer is called virtualizationvirtualization. Virtualization in the cloud 2021BCEF User UserImageImageAMIAMIAn imageimage ( (虚拟机镜像) ) is the state of a computer that has been saved into a file22BCEF User UserImageImageAMIAMI23BCEF User UserImageImageAMIAMIStart an Start an inst

15、anceinstanceInstance 1Instance 1An imageimage ( (虚拟机镜像) ) can be used to start an instanceinstance in the cloud (a virtual machine虚拟机)实例24BCEF User UserImageImageAMIAMIStart an Start an instanceinstanceInstance 1Instance 1Instance 2Instance 2The same image can be used to start many instances实例实例25BC

16、EF User UserImageImageAMIAMIStart an Start an instanceinstanceInstance 1Instance 1Instance 3Instance 3Instance 2Instance 2Multiple instances can be run on the same computer实例实例实例26BCEF User UserImageImageAMIAMIStop an Stop an instanceinstanceInstance 1Instance 1Instance 3Instance 3Instance 2Instance

17、 2The user can stop an instance.The user can restart an instance.实例实例实例27BCEF User UserImageImageAMIAMIInstance 1Instance 1Instance 3Instance 3END实例实例1) Virtualization makes it easy to do makes it easy to do load load balancing balancing (负载平衡):Each computer in the cloud can run several virtual mach

18、ines.If a computer is too busy, the state of some state of some of its virtual machines can be saved.of its virtual machines can be saved.Then, these virtual machines can be sent to sent to other computersother computers that are less busy.The other computers can continue running these virtual machi

19、nes.281) makes it easy to do makes it easy to do load balancing load balancing (负载平衡):29BCEFInstance 1Instance 1Instance 3Instance 3Instance 2Instance 2CLOUDCLOUD1) makes it easy to do makes it easy to do load balancing load balancing (负载平衡):30BCEFInstance 1Instance 1Instance 3Instance 3Instance 2In

20、stance 2CLOUDCLOUD1) makes it easy to do makes it easy to do load balancing load balancing (负载平衡):31BCEFInstance 1Instance 1Instance 3Instance 3Instance 2Instance 2CLOUDCLOUD2) It allows users to use an allows users to use an operating operating system system that they like or need:that they like or

21、 need:e.g. e.g. some people prefer using Linux instead of Windowse.g. e.g. some people want to use some applications that run only on Windows or on Linux323) It increases 3) It increases security:security:All virtual machines All virtual machines running on a same computer areare isolatedisolated fr

22、om each other each other (彼此隔离).A user running applications in a virtual machine will notnot be able to stealsteal datadata (窃取数据) in another virtual machine or cause other security problems (viruses, etc.).33BInstance 1Instance 1Instance 3Instance 3Instance 2Instance 2MaryPaulBobIf a hacker takes c

23、ontrol of a virtual machine hacker takes control of a virtual machine on a computer, he will not have access to the other virtual machines.34BInstance 1Instance 1Instance 3Instance 3Instance 2Instance 2MaryPaulBobHacker4) It is easy to manage computer resources:4) It is easy to manage computer resou

24、rces:Modern virtualization software virtualization software (applications 应用) allows to define how how much much resourcesresources can be used by each virtual machine. processor time, memory, storage space.Thus, resources can be reserved resources can be reserved and guaranteedguaranteed for each u

25、ser.35PaulMaryLea10 % of theCPU50 % of theCPU40 % of theCPU5) It allows 5) It allows elasticity elasticity (弹性计算)If virtual machines are too busy or do not have enough resources, the state of a virtual machine can be saved and copied to other computers.These computers can run copies of the virtual m

26、achine.36BCEFInstance 1Instance 1Instance 3Instance 3Instance 2Instance 25) It allows 5) It allows elasticity elasticity (弹性计算)If virtual machines are too busy or do not have enough resources, the state of a virtual machine can be saved and copied to other computers.These computers can run copies of

27、 the virtual machine.37BCEFInstance 1Instance 1Instance 3Instance 3Instance 2Instance 25) It allows 5) It allows elasticity elasticity (弹性计算)If virtual machines are too busy or do not have enough resources, the state of a virtual machine can be saved and copied to other computers.These computers can

28、 run copies of the virtual machine.38BCEFInstance 1Instance 1Instance 4Instance 4Instance 2Instance 2Instance 3Instance 3Instance 5Instance 55) It is easy to 5) It is easy to monitor performance monitor performance (监视性能)The performanceperformance of each virtual each virtual machine can be monitore

29、d machine can be monitored easily in term of: processor time, network usage, storage space, etc.This is importantimportant for the “pay for pay for what you usewhat you use” modelmodel of cloud computing.39It is useful to have: powerful processors powerful processors (强大的处理器), enoughenough memory an

30、d memory and storagestorage spacespace, , hardware support hardware support (硬件支持)(new computers often have specific hardware features to support virtualization), 40For exampleFor example, consider the Amazon EC2 CloudAmazon EC2 Cloud.A useruser can create an Amazon Machine Image (AMI)Amazon Machine

31、 Image (AMI) containing an operating system.He can then run the image on as many virtual machines as he wants in the cloud.He use monitoringmonitoring and management toolsmanagement tools provided by Amazon.411) Full virtualization 1) Full virtualization (全虚拟化): the virtual machine is an exact copy

32、of the physical hardware physical hardware (物理硬件) of a computer.a typical desktop computerany operating system operating system that can run on the real hardware can also run in the virtual machine.Windows, Linuxany applicationsapplications for the operating system can be used. Wechat, QQ,4243Comput

33、erSome video games were once only played on a video game console and a TVBut using a virtual machine, we can also play these games on a computer.2) Paravirtualization 2) Paravirtualization (半虚拟化): the virtual machine does notnot support all functions of the physical hardware.thus, the operating syst

34、em and applications must be modifiedmodified to run on the virtual machine.44To run multiple machines To run multiple machines at the same time on a computer, a software called a virtual machine manager (VMM)virtual machine manager (VMM) is often used.SomeSome are run from an operating system are ru

35、n from an operating system such as Windows or Linux e.g. e.g. Red Hat Virtual Machine ManagerOthers are run directly on the Others are run directly on the hardware hardware (硬件) e.g. e.g. Oracle VM server45What can it do?What can it do?create, start and stop virtual machines,save or load a virtual m

36、achine,monitor the performance of virtual machines (in real-time, or over a period of time),46It has been first used in the 1950s.19591959: a computer named Atlas was using a virtual memory (United Kingdom 英国)VirtualizationVirtualization is a general concept that is not only applied to virtual machi

37、nes.475.1VirtualizationVirtualization simulates access to a simulates access to a physical object physical object by four ways: 1.1.Multiplexing Multiplexing (多路复用 ): Create multiple virtual objects using one physical object.(e.g. e.g. a processor is shared by multiple applications)485.12.2.Aggregat

38、ion Aggregation (聚集): : Create a virtual object from multiple physical objects.(e.g. e.g. several hard drives are viewed as a single hard drive by a computer)3.3.Emulation Emulation (仿真 ): : Construct a virtual object from a different type of physical object.(e.g. e.g. the hard drive of a computer i

39、s used to simulate the RAM memory of a computer)4.4.A combination of 1 and 3.A combination of 1 and 3.495.1An operating system running in a virtual machine is called a “guest operating guest operating systemsystem” (客户操作系统).A guest operating system guest operating system interacts with virtual hardw

40、are in the same way that it would interact with real hardware.The virtual machine manager (VMM) virtual machine manager (VMM) traps all interactions between the guest guest operating system operating system and the real hardware.50Guest operating systemin virtual machineVirtual machine managerVirtua

41、lization has side effects side effects (副作用).Performance may not be so goodPerformance may not be so good:All operations performed in a virtual machine are intercepted by the VMM before being executed.Because of this, a virtual machine may be slow.In general, running an application in a virtual mach

42、ine is always slower.51Higher hardware costsHigher hardware costs:More expensive computers expensive computers may be bought for running virtual machines (VMs) compared to computers running a traditional operating systemWhy? Why? Virtualization needs faster and/or aster and/or multicore processorsmu

43、lticore processors, more memory, larger disks, and a faster network access.52A computer system can be viewed as a set of layers:A computer system can be viewed as a set of layers:535.2An applicationapplication typically interacts with the hardware (the processor, memory and storage) by first communi

44、cating with the operating system. Then the operating system tells the hardware what to do.A computer system can be viewed as a set of layers:A computer system can be viewed as a set of layers:545.2Or an application can run directly on the hardware. This is the case of the operating systemoperating s

45、ystem.55Computer (电脑）Operating System (操作系统) e.g. Windows56Computer (电脑）Operating System (操作系统) e.g. WindowsApplications (应用）57Computer (电脑）Operating System (操作系统) e.g. WindowsVirtual Machine Manager (虚拟机管理器)Applications (应用）58Computer (电脑）Operating System (操作系统) e.g. WindowsVirtual Machine Manager

46、(虚拟机管理器)Virtual Machines (虚拟机)Applications (应用）59Computer (电脑）Virtual Machine Manager (虚拟机管理器)60Computer (电脑）Virtual Machine Manager (虚拟机管理器)Virtual Machines (虚拟机)It managesmanages howhow resourcesresources of a computer are shared are shared between one or more virtual machines.It monitors performa

47、nce monitors performance and takes actions when performance is not good. e.g. e.g. If not enough RAM memory is available, the content of a virtual machine may be saved to disk to free some memory.615.3It checks what the virtual machines checks what the virtual machines or applications or application

48、s are doing to ensure to ensure safety.safety.62The processorprocessor of a computer (CPU) can perform a set of operations.A modern processor often offer three modesthree modes:1.1. Kernel mode Kernel mode (内核模式): any operations can be performed on the processor. (e.g. e.g. this mode is used by the

49、operating system such as Windows and the VMM)632.2. User modeUser mode: some operations considered dangerous (for security) are not allowed to be performed on the processor (e.g. e.g. this mode is used by applications to protect the operating system)3.3. Virtual machine modeVirtual machine mode: thi

50、s mode restricts what a virtual machine can do on the processor (e.g. e.g. this mode is often used for virtual machines to protect other virtual machines and the operating system)64System virtual machineSystem virtual machine: This type of virtual machine can run an can run an operating system opera

51、ting system such as windows and and several applicationsseveral applications. This is what we discussed mainly until now.Application virtual machineApplication virtual machine: This type of virtual machine is designed to run a single application.run a single application. e.g. e.g. Java programs that

52、 are run directly in a virtual machine without using an operating system.65The VMM supports multiple virtual machines and runs directly on the hardware66AdvantageAdvantage: performanceExampleExample: VMWare ESXThe VMM runs under an operating system67AdvantagesAdvantages: The VM is easier to installThe VM can use some components of the operating systemDisadvantageDisadvantage:Slower! ExampleExample: VirtualPC, VirtualBox性能代价Using a virtual machine is slower than not using a virtual machine.How much slower depends on the depends on the type of