1

ArchitectureVirtual Machine Monitor (VMM)

• CPU needs to switch between host process and guest process

• VMM switches context between those processes

• Computer runs either host context or VMM context

• Only one operating system can "run" on CPU

• Ring compression

2

Architecture

Win2003 or WinXP

Kernel VMM.sys

Ring 0

Hardware

Ring 1

Ring 3

Windows in VM

VM Additions

Guest Applications

Ring 3

Virtual ServerService

IIS

AdminWeb Site

Provided by

Windows

Virtual Server

Others

Virtual hardware

Host Guest (VM)

Ring 1

3

CPU virtualizationStill one problem left to solve

• We want CPU direct-mode execution

• Guest OS runs directly on CPU - fast! (99% speed)

• When a priviliged operation is required, a trap occurs, and VMM handles operation in kernel mode

• Problem: x86 is not fully virtualized in this way

• 20 kernel-mode read CPU instructions are allowed from outside ring 0 !

• Four possible solutions:

a) Recompile OS and applications without those 20 instructions

• = avoid those 20 instructions

b) Use Binary Translation execution

• = patch code while running on host

c) Install VM Additions in guest

• = patch code in memory in VM

d) Use hardware-assisted virtualization

• = catch instructions in special ring "-1"

4

CPU virtualizationSolutions

• Binary translation

• Translate guest instruction code to host instruction code

• Always possible, but is very slow

• VM Additions

• Patches dll-code in memory in VM (=similar to a rootkit)

• Not possible for 64-bit Vista/Longhorn

• Note that VM Additions also do:

• Time-sync, heartbeat, shutdown supportoptimized SCSI disk, and better mouse/video driver

• Hardware-assisted virtualization

• Use Intel VT or AMD Virtualization CPU

• CPU solves the problem by maintaining settings per VM

• Can be considered as ring "-1"

VM AdditionsVersions

Build Release Notes

10.21 with Virtual PC 5.2 (was named Virtual PC Additions)

13.40 with Virtual PC 2004

13.187 (download) Supports Win XP SP2

13.206 with VS2005

13.306 with Virtual PC 2004 SP1

13.518 with VS2005 SP1 beta

13.531 (download) Supports Win2003 SP1

13.552 with VS2005 R2 Supports Win2003 R2 and Vista (-build 5270)

13.705 with VS2005 R2 SP1 beta1

13.706 (download - Connect) Supports Vista B2 (-build 5384) and Longhorn

13.709 (download - Connect) Supports Vista RC1

13.715 with VS2005 R2 SP1 beta2 Supports Vista RTM

13.724 with Virtual PC 2007 beta

13.802 with Virtual PC 2007 RC Get at connect.microsoft.com/site/sitehome.aspx?SiteID=288

6

VM AdditionsLinux

• Adds:

• time sync

• Heartbeat

• shutdown support

• SCSI disk

• mouse/display driver

• But not direct-mode execution support

• Distributions (9x)

• Red Hat 7.3/9.0, Enterprise 2.1/3/4

• SuSE Linux 9.2/9.3/10.0, Enterprise Server 9

• More available at release VS 2005 R2 SP1

7

ArchitectureHardware-assisted virtualization

Win2003 or WinXP

Kernel VMM.sys

Ring 0

Hardware

Host Guest (VM)

Ring 1

Ring 3

Windows in VM

VM Additions

Guest Applications

Ring 3

Virtual ServerService

IIS

AdminWeb Site

Provided by

Windows

Virtual Server

Others

Virtual hardwareCPU

Ring "-1"

8

Hardware-assisted virtualizationIntel VT or AMD Virtualization

• Supported in:

• Virtual PC 2007

• Virtual Server 2005 R2 SP1

• Windows Virtualization (is requirement)

• Enable in BIOS

• Plus enable in Virtual PC 2007 Options

• Windows guests do not run faster

• Up-to-date VM Additions already provide direct-mode execution

• Windows installation is 2x-3x faster

• Non-Windows guests (Linux, Netware) run faster

9

Virtual Server 2005 R2Specifications

• Host

• CPU

VS2005 Standard Edition: max 4 CPUs (1 or 2 cores)

• VS2005 Enterprise Edition: max 32 CPUs (1 or 2 cores)

• Memory: max 64 GB

• Guest

• CPU: max 1

• Memory: max 3.6 GB

• Network adapters: max 4

• Unlimited bandwidth !

• USB: no

• USB keyboard/mouse is supported

• Workaround for USB smartcard-readers exists !

10

Virtual Server 2005 R2What's new

• Performance

• Increased performance

• Scalability

• x64 hosts: Win2003 and WinXP

• Availability

• Virtual Machine clustering

• Failover VM on same host

• Uses Shared SCSI (or iSCSI) in guest

• Virtual Server Host clustering

• Move VS2005 to other host

• Planned and unplanned downtime

• Requires script - http://go.microsoft.com/fwlink/?LinkId=55644

11

Virtual Server 2005 R2What's new (cont'd)

• Additional guest support+ Win2003 SE SP1

+ WinXP SP2

• PXE Booting

• F6 disk (SCSI disk)

• Speeds up Windows installation

• Virtual Disk Precompactor.iso

• Also...

• Supports hyperthreading on host

• Reserve space for save state file (.vsv)

• Open Windows Firewall ports at install

12

Virtual Server 2005 R2 SP1What's new

• Features

• Intel VT and AMD Virtualization support

• Volume Shadow Copy (VSS) support

• Active Directory integration using Service Connection Points

• Vista as Guest support

• Includes VHD mount tool

• Also...

• Host clustering whitepaper included

• Default vhd capacity is 127 GB (was 16 GB)

• Virtual SCSI fix for Linux 2.6.x guests

13

Differences VS2005 - VPC2007

• Virtual Server 2005:

• Use multiple host CPUs

• Multithreaded

• Multiple CD ROM drives

• NAT through host ICS

• Unlimited networks

• Using vnc-files on host

• Only in VS2005:

• SCSI disk (in VM)

• COM API

• Remote Management

• Run as service

• Auto start VMs

• Virtual PC 2007:

• Use single host CPU

• Single thread for all VMs

• Single CD ROM drive

• NAT support

• Unlimited networks

• Using host (loopback) adapters

• Only in VPC2007:

• Sound card (VM)

• Folder Sharing

• Drag-and-drop

• Copy / Paste

14

Windows VirtualizationVMM arrangements

Hardware

Host OS VMM

Guest 1 Guest 2

Hardware

VMM (Hypervisor)

Guest 1 Guest 2

Hardware

VMM

Guest 1 Guest 2

Host OS

Type-2 VMM

Examples:- JVM- .NET CLR

Examples:- Virtual PC- Virtual Server

Example:- Windows Virtualization ("Viridian")

Type-1 VMMHypervisor

Hybrid VMM

15

Windows Virtualization

• Virtualization for Windows Server

• Code name "Viridian" (= color: rgb 64-130-109 )

• Windows Hypervisor

• Thin layer of software, underneath "host OS" (~160 KB)

• Parent partition - manages child partitions

• Child partition - any number of OS, managed by parent

• Virtualization Stack

• Runs in root partition (= parent partition)

• Provides virtualization of devices

• WMI interface for management

• Virtualization Service Providers (VSPs)

• Hardware sharing architecture

• Need "viridian" drivers in guest

16

Windows Virtualization

• Virtualization for Windows Server• Requires

• x64 hardware

• Intel VT / AMD-V processor

• Provides• 32-bit and 64-bit guest

• Max 8 CPU per VM

• Hot "add": processor, memory, network, disk

• 32+ GB RAM per VM

• Live virtual machine migration

• Multiple snapshots

• No new driver model• Can use existing Windows drivers in guest

• Same set of emulated hardware• S3 Trio video card, DEC 21440 network card, etc

• Support for Server Core as parent OS

17

ArchitectureVirtual PC / Virtual Server 2005 R2

Win2003 or WinXP

Kernel VMM.sys

Ring 0

Hardware

Host Guest (VM)

Ring 1

Ring 3

Windows in VM

VM Additions

Guest Applications

Ring 3

Virtual ServerService

IIS

AdminWeb Site

Provided by

Windows

Virtual Server

Others

Virtual hardware

18

Windows Virtualization

Windows (core)

Kernel

Windows Hypervisor

Ring 0

Hardware

Parent partition Child partition

Ring 3Guest Applications

Ring "-1"

Windows

VMBusEnlightments

KernelVSPs VSCs

Virtualization Stack

VM Service

WMI

VM Worker

Provided by

Windows

Win Virtualizaton

Others

Drivers

19

Windows VirtualizationVSC - VSP Communication

Parent Partition Child Partitions

Kernel ModeKernel Mode

User ModeUser Mode

Windows hypervisorWindows hypervisor

ApplicationsApplications

Provided by:Provided by:

WindowsWindows

ISVISV

Windows Windows

VirtualizationVirtualization

VMBusVMBus

Windows File SystemWindows File System

VolumeVolume

PartitionPartition

DiskDisk

Fast Path Filter (VSC)Fast Path Filter (VSC)

iSCSIprtiSCSIprtVirtual StorageVirtual Storage

Miniport (VSC)Miniport (VSC)

Virtual ServiceVirtual Service

Provider (VSP)Provider (VSP)

StorPortStorPort

Hardware

StorPortStorPort

MiniportMiniport

VM Worker ProcessVM Worker Process

DiskDisk

20

Virtual Server 2005 vsWindows Server Virtualization  Virtual Server 2005 R2 Windows Server Virtualization

32-bit VMs? Yes Yes

64-bit VMs? No Yes

Multi-processor VMs? No Yes, up to 8 processor VMs

VM memory support? 3.6 GB per VM More than 32 GB per VM

Hot add memory/processors? No Yes

Hot add storage/networking? No Yes

Can be managed by System Center Virtual Machine Manager?

Yes Yes

Microsoft Cluster support? Yes Yes

Scriptable / Extensible? Yes, COM Yes, WMI

Number of running VMs? 64More than 64.

As many as hardware will allow.

User interface Web Interface MMC 3.0 Interface

21

Networking

• Create .vnc-files to define "virtual switches"

• Three settings per vnc-file:

• - Network name

• - Connected to which host network adapter or to None (guest-only)

• - DHCP settings for this switch

• Pre-defined vnc-files:

• Internal network.vnc

• Separate vnc-file for each host network adapter

• Unique MAC-address assigned

• Unlimited network speed (not max 10/100 Mbps)

22

Disks

• Data store in virtual hard disk (.vhd) files

• File format is the same:

• Virtual PC 2004

• Virtual Server 2005

• Windows Virtualization (future)

• Max sizes

• IDE (VPC2004): 130,557 MB (= 127.5 GB)

• IDE (VS2005): 130,048 MB (= 127.0 GB)

• SCSI (VS2005): 2,088,960 MB (= 2040.0 GB)

23

DisksVHD Format

• Free license from Microsoft

• www.microsoft.com/windowsserversystem/virtualserver/techinfo/vhdspec.mspx

• 45 vendors signed up (April 2006)

• Examples:

• Diskeeper

• PlateSpin

• WinImage

• XenSource

• From 17-Oct-2006:

• Unregistered download available

Virtual Hard Disk Format Specification

• Introductions• Overview of Virtual Hard Disk Types• Virtual hard disk Footer Format• Dynamically expanding .VHD Header Format• Block Allocation Table and Data Blocks• Implementing a Dynamically expanding .VHD• Mapping a Disk Sector to a Sector in the Block• Splitting virtual hard disks• Implementing a Differencing virtual hard disk• CHS Calculation

24

VHD Types

Base VHD types

Dynamically expanding

Default type: Grows as needed

Fixed size Highest performance type

State drive types

Undo Non-persistent, per VM (*.vud)

Differencing Persistent parent-child hierarchy

Saved states Flush memory to disk (*.vsv)

GuestGuest

HostHostGuestGuest

2TB2TB

2TB2TB

2TB2TB

VMVM

HostHost

SP1SP1 SP2SP2

HostHost 2TB2TB1GB1GB

BaseBase

BaseBase SessionSession

25

VHD Test Drive Program

• New: announced 6-Nov-2006

• Fully configured VHD-files

• Downloadable from Microsoft's Web site

• Evaluation versions

• Expires after 30 days

• Partners can also provide their applications

• See www.microsoft.com/vhd for more information

26

VHD Mount ToolAccess VHD content offline

• VHDMount tool is included with VS2005 R2 SP1

• Can install separate:

• Use as command-line tool:

• Use for copying or injecting files, inspecting, virus-scanning

• Do not use for offline patching (yet)

C:\> msiexec.exe /i "Virtual Server 2005 Install.msi" /qn ADDLOCAL=VHDMount

C:\Program Files\Microsoft Virtual Server\Vhdmount> vhdmount.exeUsage:VHDMOUNT /p VHDFileName - mounts vhd-fileVHDMOUNT /m VHDFileName [DriveLetter] - mounts vhd-file, assign drive lettersVHDMOUNT /u VHDFileName | All - unmounts vhd-file or allVHDMOUNT /q VHDFileName | All - lists mounted vhd-file or all

27

VHD EnhancementsWindows Virtualization

• While VM is running

• Compact VHD-file

• Create new diff-disk (snapshotting)

• Create VHD-chain

• Schedule snapshot every 10 minutes

• Merge

• Hot add VHD-file

• Add VHD-file notes

• Think: 1000s of VHD-files on network

• Pass-through VHD - map to SAN

28

Differencing disks

• VHD files use blocks of 2 MB

Read

File-a.doc

1 2 3 4

File-b.doc

1 2 4

Create

File-c.doc

1 2 3 4Grow

File-d.doc

Read only

Virtual Server service

3

Write

3

3 1 2 3 4

Delete

File-d.doc

1 2 3 4

Link toparent

29

DisksRead/write zero-filled files• VHD file format optimizes read/write of

zero-filled blocks

• Best example: empty pagefile.sys

Write

File-a.doc

1 2 3 4

1 2 3 4

Pagefile.sys

Write

1000000000000

2 4000000000000

3000000000000

5...

1 4

Read

000000000000

11000000000000

12

Virtual Server service

30

Compact VHD Files

• Steps

• Note: Does not work on differencing disks

• In VM - Cleanup

• Startup VM without Undo disks

1 Defragment disk

2 Zero-fill all unallocated spaces

• Use Precompactor.iso

• Shutdown VM

• On host - Compact

3 Use VPC Disk Wizard or VS Inspect Disk to compact

31

Virtual Server Clustering

• Three different options

• Virtual Machine (Guest) Clustering - Shared SCSI

• Cluster VMs on same host

• Virtual Machine (Guest) Clustering - iSCSI

• Cluster VMs on different hosts

• Virtual Server Host Clustering

• Cluster VS on different hosts

32

Clustering

Host to Host

Cluster storage

SAN or iSCSI connection

Guest to Guest

Cluster storage

iSCSI connection

33

ClusteringVirtual Machine (Guest) Clustering

• VM (Guest) is the cluster node

• Application in guest is a resource group

• Application is cluster-aware (or Generic)

• Protects against failure of Guest

• If VM or application fails,then failover to other VMon same host or on another host

34

Out-of-the-Box High AvailabilityHost Updating

• Administrator wants to update node 1 with Windows Server Update Services

• Microsoft Cluster Administration Console saves the state of virtual machines and restores them on another node

• Node 1 is ready for update installation

SharedStorage

VM

VM

VM

Node 1 Node 2 Node 3

Shared Storage

WSUS server

WSUS

35

Out-of-the-Box High AvailabilityUnplanned downtime

• Node 1 suffers a power outage or a network failure

• A simple script attached to the Microsoft Cluster Administration Console notices the lack of heartbeat and starts the virtual machines associated with node 1 on other nodes

SharedStorage

VM

VM

VM

Node 1 Node 2 Node 3

Shared Storage

X

36

ClusteringVirtual Server Host Clustering

• Host is the cluster node

• Each VM (Guest) is a resource group

• Generic Script havm.vbs makes VM "cluster-aware"

• Protects against failure of Host

• Application in guest is not monitored by cluster

Function Open() [..] 'starts Virtual Server serviceFunction Online() [..] 'send start control to VMFunction LooksAlive() [..] 'quick check if VM is aliveFunction IsAlive() [..] 'thorough check if VM is aliveFunction Offline() [..] 'send save state control to VMFunction Terminate() [..] 'best attempt to take offline

37

ClusteringVirtual Server Host Clustering

• Benefits

• Move VMs before scheduled host maintenance

• Hardware upgrades

• Software updates on host

• Steps: Saves state VM1 - failover - restore state in VM2

• Protect against unscheduled host failure

• Steps: (Oops) - failover - startup VM2

• Run legacy operating systems in a "clustered" way

38

ClusteringVirtual Server Host Clustering

• Deploy

• Hosts run Cluster service

• Uses iSCSI or SCSI/Fibre Channel to shared storage

• Note: Disable Cluster service when installing VS2005

• Each VM is in a Resource Group

• Or multiple VMs in same Resource Group

• Implemented as Physical Disk resource

• Containing vmc-file, vhd-file and vsv-file

• Add havm.vbs as Generic Script in Resource Group

• Resource dependencies:

• Script havm.vbs OS disk Data disk