Virtualization

1. Virtualization Chapter 19

2. Overview In this chapter, you will learn how to Describe the concepts of virtualization Explain why PC and network administrators have widely adopted virtualization Describe how virtualization manifests in modern networks

3. Introduction to Virtualization • Virtualization is the “next big thing” in the computer industry. • Virtualization creates a complete environment for a guest operating system to function as if it were installed on its own computer. • Guest environment is called a virtual machine (VM). • Individual machines or entire networks can be virtualized.

4. Introduction to Virtualization (continued) Figure 1: VMware running Linux

5. What Is Virtualization?

6. What Is Virtualization? • Most people have heard of “virtual reality.” • A “virtual” world is created by software, with sight and sound provided by video and audio equipment. • Primarily used for gaming, flight simulation, etc. • Equipment such as goggles and special gloves enables you to “see” and “move” objects. • Computer virtualization is similar • “Virtual” operating system • Software computer (guest) running on hardware host • Allows multiple different operating systems to run

7. What Is Virtualization? (continued) Figure 2: Virtual reality training (photo courtesy of NASA)

8. What Is Virtualization? (continued) Figure 3: Using virtual reality to practice spacewalking (photo courtesy of NASA)

9. Computer Virtualization • Similarly, computers and networks can be virtualized. • Virtualization convinces an operating system that it’s running on its own hardware. • The virtualization software runs on a host operating system that is physically installed on a machine. • The guest operating systems are the virtual machines. • Virtualization uses hypervisors or virtual machine managers to create and manage virtual machines and their interactions with their host environments.

10. Meet the Hypervisor • A normal OS uses a program called a supervisor. • Handles very low-level interaction among hardware and software (i.e., task scheduling, allotment of time and resources, etc.) • Full virtualization requires an extra layer of programming to manage the complex interactions between the host and guest machines. • Enter the hypervisor or virtual machine manager (VMM).

11. Meet the Hypervisor (continued) • The hypervisor handles the input and output requests an operating system would make of normal hardware. • It allocates real hardware (drives, RAM, media, etc.) from the host to the virtual machines. • It enables easy addition and removal of virtual hard drives, virtual network cards, virtual RAM, etc.

12. Meet the Hypervisor (continued) Figure 4: Configuring virtual hardware in VMware Workstation

13. Meet the Hypervisor (continued) Figure 5: System setup utility in VMware Workstation

14. Emulation vs. Virtualization • Virtualization uses hardware from the host system and divides it into individual virtual machines. • It abstracts hardware that runs on the same platform. • It cannot virtualize hardware that is on a different platform (an Intel platform cannot virtualize a Sony PlayStation). • Emulation is very different. • It enables software written for a different platform to run, but it does not virtualize the hardware.

15. Emulation vs. Virtualization (continued) • An emulator is software or hardware that converts the commands to and from the host machine into an entirely different platform. • For example, an emulator makes it possible to run game console software on a PC.

16. Emulation vs. Virtualization (continued) Figure 6: Super Nintendo emulator running on Windows

17. Sample Virtualization • The following slides take you through a quick tour of virtualization. • They show the steps involved in setting up and installing a virtual machine and its guest OS. • In this example, Windows 7 is the host OS. • VMware Workstation is the VMM. • Ubuntu is installed as the guest OS.

18. Sample Virtualization (continued) Figure 7: VMware Workstation

19. Sample Virtualization (continued) Figure 8: Selecting a Typical or Custom setup

20. Sample Virtualization (continued) Figure 9: Selecting the installation media

21. Sample Virtualization (continued) Figure 10: Setting the virtual drive size

22. Sample Virtualization (continued) Figure 11: Entering the VM name and location

23. Sample Virtualization (continued) Figure 12: Ubuntu installing into the new virtual machine

24. Sample Virtualization (continued) Figure 13: VMware Workstation with a single VM

25. Sample Virtualization (continued) Figure 14: POST in a virtual machine

26. Why Do We Virtualize?

27. Why Do We Virtualize? • Virtualization provides two key benefits: • It reduces the number of physical machines. • Virtual machines are simply files, making it easy to manage backups, security, portability, etc. • Other important reasons include • Power savings • Hardware consolidation • System recovery • System duplication • Research

28. Power Savings • Before virtualization, each server OS required its own unique physical system. • With virtualization, you can place multiple virtual servers on a single physical system, reducing electrical power use. • Expanding this electricity savings over an enterprise network or on a data center is cost effective and “green.”

29. Hardware Consolidation • A physical high-end server represents a substantial investment in hardware—multiple processors, RAID arrays, redundant power supplies, and RAM. Setting up multiple physical high-end servers can be very expensive. • Virtualization makes it possible to increase RAM and run a number of servers on a single machine.

30. System Recovery • The most popular reason for virtualization is to keep a high uptime percentage. • If a system goes down, you need to quickly restore the system from a backup. • Virtualization makes it possible to shut down the VM and reload an alternative copy. • Snapshots enable you to make a point-in-time exact copy of the virtual machine that can be used in case of an emergency restore.

31. System Recovery (continued) Figure 15: Saving a snapshot

32. System Duplication • VMs are simply files that can be copied. • VMs can be mass-duplicated by copying the files to the target machine. • This makes it possible to deploy numerous servers with similar baseline operating systems. • Useful in research or teaching environments

33. Research • Virtualization makes it possible to reduce the number of research and testing machines. • It can streamline the equipment necessary in these areas: • Product testing and research • Security testing and research • Development testing before production

34. Research (continued) Figure 16: Lots of VMs used for research

35. Virtualization in Modern Networks

36. Virtualization in Modern Networks • The products we’ve discussed so far offer virtualization over operating systems: • VMware Workstation • Microsoft Virtual PC • They are suitable for small implementations with few virtual machines. • Large-scale implementations require a different approach.

37. Virtualization in Modern Networks (continued) • Virtualization in large-scale networks uses “bare-metal” hypervisors. • No operating system is necessary. • The virtualization software is the OS. • The hypervisor eliminates all the unnecessary OS overhead. • VMware introduced ESX in 2001. • It was an early serious large-scale bare-metal hypervisor. • It has a small storage footprint and can be installed on and booted from a USB flash drive.

38. Virtualization in Modern Networks (continued) Figure 17: USB drive on server system

39. VMMs vs. Hypervisors • A virtual machine manager (VMM) is virtual machine software that runs on top of a host operating system. • Example: VMware Workstation • A hypervisor is software that does not need a host operating system. • Example: ESX Server

40. Virtual Machine Managers • Many choices are available for Linux, Windows, and Mac OS: • VMware Workstation • Microsoft Virtual PC • Parallels • KVM

41. Virtual Machine Managers (continued) • VMware Workstation • Industry leader in virtualization • Comes in versions for Linux and Windows • Offers features such as VMTools that make interactions between guest and host OS seamless

42. Virtual Machine Managers (continued) • Virtual PC • Microsoft VMM that runs over various iterations of Windows • Free product • Some limitations • Officially supports Windows VMs, but Linux VMs can be installed and managed

43. Virtual Machine Managers (continued) Figure 18: Windows Virtual PC

44. Virtual Machine Managers (continued) • Parallels • Most popular virtualization manager for Mac OS X (followed by VMware Fusion) • Supports all popular operating systems and even has good 3-D graphics support

45. Virtual Machine Managers (continued) Figure 19: Parallels for Mac

46. Virtual Machine Managers (continued) • KVM • Open-source virtualization product from Red Hat • Represents Linux/Unix world • Supports a few non-x86 processors • Other open-source contenders include Xen and Oracle’s VirtualBox

47. Hypervisors • There are several choices, but two are dominant in the market: • Vmware’s ESX • Microsoft’s Hyper-V

48. Hypervisors (continued) • ESX • Market leader; offers several features: • Support for large storage (SAN and NAS) • Transparent and automatic fault tolerance • Transparent server transfer—you can move a running VM from one machine to another • Support for up to 32 CPUs, depending on the version

49. Hypervisors (continued) • Hyper-V • Microsoft’s contender in virtualization • Free product • Previously only part of Windows Server 2008—now also available as stand-alone product • Available for 64-bit systems