Understanding Virtualization in Longhorn Server

Presented by Mark Minasihelp@minasi.com

Talk originally created by Michael OteyTechnical Director Windows IT Pro Magazine

What this session covers

• Virtual machine basics

• Virtualization scenarios

• Virtualization with Virtual Server 2005 R2

• Virtualization with Windows Server Longhorn and the Hypervisor

• Managing VMs with upcoming tools

• FAQs about Windows Server Virtualization

Virtual Possibilities• Create a set of uniform server builds, even on

dissimilar hardware• Simplify disaster recovery• Reduce hardware costs• Reduce infrastructure costs• Simplify testing• Archive existing systems• Virtual "appliances" and easily-implemented

demonstration software

Understanding Virtual Machines

Basic Ideas

• Take an actual computer

• Build software to allow it to create imaginary computers, "virtual machines"

• After creating a virtual machine, it acts like a computer without an OS when booted

• Install software on it just as you would on an actual machine

Virtual Machine Virtualization

System Hardware

Host Operating System

Virtual Machine Manager

Virtual Machine

Guest OS(Windows 2003)

Applications

Virtual Machine Virtual Machine

Guest OS(Windows NT)

Guest OS(Windows 2000)

Applications Applications

V i r

t u

a l

P h

y s

i c

a l

Major Players

• Microsoft Virtual Server 2005 R2, Microsoft Virtual PC 2007

• Longhorn Server "Hypervisor"

• VMWare Workstation ($), VMWare Server, VMWare Player, VMWare ESX ($)

• Xensource Xen

This Isn't New!

• Need in the early 80s for virtual machine managers for PC-DOS/MS-DOS apps

• Very hard to do until 386 architecture arrived

• The difference: a special "v86" mode

• Exploited by Windows 386, DesqView, Windows 3, OS/2 2.x and even by Windows NT

But It Stopped There…

• So the 386 was excellent at creating bunches of imaginary 8086s

• But not at creating imaginary 386es!

• Rumors had it that a new chip, the 80486, could virtualize itself

• But it never really happened; there wasn't a Pentium-class chip that could fully virtualize a Pentium-class chip

So How Does Virtual PC Do It?

• It should be impossible, then, to create virtual machine managers

• But some smart folks figured it out

• The original tool that eventually became Virtual PC actually emulated Pentiums on

a Mac

• Another group out of CMU figured another way

But Virtual Machines are Limited…

• VMMs make Pentium-type systems simulate more Pentiums

• But while they work by emulating hardware, they do not emulate CPUs, as that would be far too slow

• Thus, at some point the VMM has to hand instructions ("opcodes") over to the actual processor

• Much of the issue lies also in the four Intel "rings" of privilege (3's the lowest, 0 most power)

Problem and Solution

• There are ten opcodes that can "get out of hand" VMM wise

• Answer: new line of chips that include a new "ring -1" privilege

• Intel: "Vanderpool" "VT" technology

• AMD: "Pacifica" or "V" technology

• AMD's implementation is a superset of Intel's

• Not compatible, so VMMs must recognize and handle AMD and Intel changes, or just limit it self to the common capabilities

More on V/VT

• Bottom line: we finally have Pentiums that can fully virtualize Pentiums!

• Intel manages VM memory in software, AMD does it in hardware

• Adding the 10 opcodes and "ring -1" makes building VMWare, Virtual Server and Xen much easier, and makes the VMMs more reliable

Virtualization Overview

• Virtual Machine Guest Environment

Where VMs Live

• While not running, a VM is nothing more than a set of files representing

– the hard disk(s) on a VM

– the contents of RAM when "snapshotted"

– configuration info

• Microsoft stores this in a file with the extension ".vhd"

• VMWare uses ".vmdk"

VM Hard Disk Options

• Virtual Hard Disks

– Fixed

– Dynamic

• Virtual Hard Disk Features

– Snapshots

– Undo disks

– Differencing Disks/"Cloning" VMs

VM Networking Options

• Virtual Networking

– None

– Internal

– External (Bridged)

– "Virtual subnets"

Virtual Machine Additions

• Installed after the guest OS– Typically from installed IS image– Improves VM performance

• Enhanced SVGA video drivers• Improved mouse support • Drag-and-drop with the host• Time synchronization• MS name: "Virtual Machine Additions"• VMWare name: "VMWare Tools"• Can cause some real troubles when converting

MS<->VMWare, so remove them beforehand!

64-bit Support

• 64-bit host support

– Windows Server SE and EE x64

• x64 eliminates physical memory restrictions

• 64-bit Virtual Machine Manager

– Larger kernel address space

64-Bit Benefit

• 64 bit OSes are quite useful, but…

• They present some compatibility issues

• For example, x64 Windows does not run 16 bit apps (and you'd be surprised how many little apps are still 16 bit, including installers!)

• Answer: create a VM with a 32-bit OS, and you can run that 16-bit app

What About Licensing?

• Typically software vendors want you to buy a license for every virtual machine or physical machine you install the software on

• Microsoft offers preferential licensing options for people using their OS software on their virtualization platforms

• Confusingly, MS forbids creating VMs from some of its OSes

• Check your licenses before implementing!

Virtual Server 2005 R2

• Features– 64-bit host support

– Web-based management

– New support for Linux distributions

– Support for Microsoft clusters

• Limitations– No 64-bit guest support

– No guest audio

– No guest USB

VS2005 R2 MSCS Host Support

• Support for Microsoft Clustering Services– Windows Server 2003

Enterprise Edition or Datacenter Edition

• VS is MSCS cluster-aware– Eliminates single point

of failure

– Automatic VM startup

Virtual Server 2005 R2 SP1

• Intel-VT & AMD-V-Aware

– Better performance

– Better Linux interoperability

• VSS Support (backups while running)

• VHD Mounting on Host

• Improved Backup & DR

Windows Server 2003 R2

• Applies to any virtualization product running on Windows Server 2003 R2

• VM licensing changes– Windows Server 2003 Enterprise Edition R2

• Base OS

• Four additional VM OS

– Windows Server 2003 Datacenter Edition• Unlimited VMs

– Even Vista Enterprise gets in the act!

• SQL Server (Enterprise) offers unlimited VMs as well

Interop 1: P2V

• Take an existing physical server and make it run as a virtual server

• Usually not very automatic, but it's possible and getting better– MS has a P2V wizard that works with Enterprise

Server 2003 R2

– VMWare has the "VMWare Converter" in free and for-pay versions

• All P2V tools have improved immensely in the past 18 months

• Good news coming soon in the MS world

Interop 2: MS/VMWare

• VMWare's free converter can change vmdk files to and from vhd files

• In some cases Microsoft forbids this license-wise, although of course there's no physical barrier

• This will all probably settle out eventually

When Does Virtualization Make Sense?

• Server consolidation

• Lab and Deployment Testing

• Training

• Disaster Recovery

Server Sprawl

• New application = new (underutilized) server

File/Print

File/Print

File/Print

Database

Database

Application

Application

Application

Application

Application

Application

Application

Application

We can put multiple functions on a single box, but we tend not to

Server Consolidation

• Increase hardware utilization

• Reduced costs

– Fewer systems

– Less power

– Less cooling

– Lower IT resources

• Reduced Infrastructure

– Fewer racks

– Fewer switches

Lab and Deployment Testing• Build a test virtual network

infrastructure

• Duplicate physical model– Same domain structure and

system names

– Virtual network clients

• Reduced physical system requirements– No need for 1-1 physical

systems

• Virtual networking– Connects virtual systems

– Isolated from production network

Training

• Present and reset training image– Just reset the VM

– No need to reimage the systems

– Network isolation

Disaster Recovery

• Fewer servers to manage and recover/restore

– Reduces costs

• Server VMs are hardware independent

– Can be restored to other platforms

– No need to match primary site and secondary site hardware

• VMs are encapsulated

– Faster

– Can be replicated between sites

– No need for bare-metal installs

Disaster Recovery

• Physical-to-VM recovery

– Restore physical backup to running VM

– Lower costs – no need for 1-to-1 physical servers

• VM-to-VM recovery

– Protects against operating system/application failure

– Recover failed VM on another server

Disaster Recovery

• How's it done?

• Remember, when inactive a VM is nothing more than a folder full of files

• The only issue is how to get it backed up

• You can just take the server down for a bit, but the better answer involves online backup

• MS's answer (VS 2005 R2 SP1) is free, VMWare's isn't

High Availability for Hosts

Primary Site Recovery Site

Virtual Server Host Clustering

Primary Site Recovery Site

Windows ServerLonghorn Virtualization

Virtual

Hard Disks

(VHD))

Windows Virtualization Platforms

Virtualization

Platform and

Management

Hardware

Windows Server 2003

Virtual Server 2005 R2

VM 2 VM 3

VM 1“Parent””

VM 2“Child”

VM 2“Child”

Windows Hypervisor Benefits

• Better performance

– Small hypervisor

– Utilizes Processor virtualization

• Intel-VT and AMD-V, full opcode support

• Small host footprint

– Combine with Windows Server Core

– Headless Virtual Server Host

• Managed using RDP, WinRS or whatever

ESX Server vs. Windows Server• Monolithic hypervisor

– Simpler than a modern kernel

– Still complex

– larger hypervisor

– Contains its own drivers model

• Microkernel hypervisor– Simple partitioning functionality– Lightweight hypervisor– No third-party code– Drivers run within guests

VM 1(“Admin”)

VM 3

Hardware

Hypervisor

VM 2(“Child”)

VM 3(“Child”)

Virtual-izationStack

VM 1(“Parent”)

DriversDriversDriversDriversDriversDriversDriversDriversDriversDrivers

DriversDriversDriversDriversDriversHypervisor

VM 2

Hardware

DriversDriversDriversDriversDrivers

VMware ESX Virtualization Windows Server Virtualization

Windows Server & Xen-enabled Linux

Windows hypervisor

Server Hardware

Basic

Linux Kernel

Applications

WindowsKernel

Longhorn Server

VSP

Windows Server 2003, “Longhorn””

Applications

WindowsKernel VSC

VMBus VMBus Emulation

Xen-enabled

Linux Kernel

Applications

VSC

VMBus

Provided by:Provided by:

OS

MS/XenSource

ISV/IHV/OEM

Windows

virtualization

Virtual Server vs WSLVirtual Server 2005 R2 Windows Server Virtualization

32-bit VMs? Yes Yes

64-bit VMs? No Yes

Multi-processor VMs? No Up to 8 processor VMs

VM memory support? 3.6 GB per VM Up to 32 GB per VM

Hot add memory/processors? No Yes

Hot add storage/networking? No Yes

Managed by System Center Virtual Machine Manager?

Yes Yes

Microsoft Cluster support? Yes Yes

Scriptable/Extensible? Yes, COM Yes, WMI

Number of running VMs? 64 Limited only by hardware resources

User interface Web Interface MMC 3.0 Interface

System Center VM Manager

• Provides P2V

• Uses historical MOM info to identify the best machines for P2Ving

• "Intelligent Placement" assists in identifying which particular physical systems would best host a given VM

• Optimizer helps you tune both a VM and its PM to get the best throughput

• Maintains VHD repository

• Totally PowerShell-able!

Centralized Management for VS2005 & Windows Server

By Resource Pool

By VM State

By Owner

By Creation Date

By Operating System

Intelligent Virtual Server Placement

Subset physical hosts to

appropriate resource pool(s)

Rank-ordered recommendations of

physical hosts for placement of virtual

machine.

End User Provisioning

Ability to control owned virtual

machines

Thumbnails of all owned virtual

machines

Virtualization FAQs

• Do I need to license Guest OSes?

– Guest OS must be licensed

– Clients need CALs

– The exception is Windows Server 2003 R2 Enterprise Edition, Datacenter Edition and Vista Enterprise

• How does guest CPU licensing work?

– Virtual CPUs count toward CPU license

– Not physical host CPUs (!)

Virtualization FAQs

• Will host clustering be supported with the Windows Server Hypervisor?

– Yes, WSL Hypervisor supports all of the features in Virtual Server 2005 R2 +

• Is the Hypervisor included with Longhorn Server?

– No. The Hypervisor is a separate download that will be available within 180 days of the windows Server Longhorn RTM

Virtualization FAQs

• Are Virtual Server VM images compatible with the Windows Server Hypervisor?

– Yes. They use the same format, VHD

• Will the Windows Server Hypervisorsupport 64-bit hosts and guests?

– Yes. Unlike VS2005 the hypervisor provides x64 support for hosts and guest VMs.

SoftGrid, Rapid no-touch deployment

System Center Virtual Machine Manager, P2V, Intelligent resource utilization

Licensed .VHD format, XENSource

Windows Server 2003 R2 EE & DE, Windows Vista

Virtual server 2005 R2, Windows Server Longhorn Hypervisor, Intel-VT & AMD-VInfrastructure

Microsoft Virtualization

Applications

Management

Interoperability

Licensing

Thank You!

Mark Minasi

help@minasi.com

www.minasi.com

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