an introduction to server virtualisation
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An Introduction to Server Virtualisation
Alan McSweeney
April 10, 2023 2
A loose definition
Virtualisation is a framework or methodology of dividing the resources of a computer into multiple execution environments, by applying one or more concepts or technologies such as hardware and software partitioning, time-sharing, partial or complete machine simulation, emulation, quality of service, and many others.
April 10, 2023 3
Some history
− An old concept – first virtual machines created on IBM mainframes in early ’60s
− Typically, IBM's virtual machines were identical "copies" of the underlying hardware. Each instance could run its own operating system.
− Virtualisation formed the basis of “time sharing”
April 10, 2023 4
Some virtual machines you may know…
− NT had Virtual DOS Machine (NTVDM) and Windows on Win32 (WOW)
− Windows 95 used virtual machines to run older (Windows 3.x and DOS) applications
April 10, 2023 5
The old model
− A server for every application
− Software and hardware are tightly coupled
− Underutilised resources introduce real cost into the infrastructure
April 10, 2023 6
The new model
− Physical hardware is abstracted by a virtualisation layer, or hypervisor
− Manage OS and application as a single unit by encapsulating them into virtual machines
− Separate OS and hardware and break hardware dependancies
− Optimise utilisation levels
April 10, 2023 7
Increased Hardware Utilisation
• Before Virtualisation • After Virtualisation
April 10, 2023 8
Underutilisation of Resources
• Most organisations over-provision− Multiple processors in
each server− Memory requirements
over-estimated
• Aim to drive up CPU utilisation
Actual DSS customer data – 120 servers monitored
April 10, 2023 9
Virtual Infrastructure
• Virtual infrastructure brings uniformity to the data centre
• Dynamically map computing resources to the business
• Lower IT costs through increased efficiency, flexibility and responsiveness
• Provision new services and change the amount of resources dedicated to a software service
• Treat your data centre as a single pool of processing, storage and networking power
April 10, 2023 10
How is it implemented?
− Typically, in order to virtualize, you would use a layer of software that provides the illusion of a "real" machine to multiple instances of "virtual machines". This layer is traditionally called the Virtual Machine Monitor (VMM) or “hypervisor”.
− The hypervisor could run directly on the real hardware or it could run as an application on top of a host operating system.
April 10, 2023 11
Type 1 VMM
Hardware
VMM
GuestVM
GuestVM
GuestVM
IBM CP/CMSVMware ESX
Windows Virtualisation (2008)Xen
Virtual Iron
April 10, 2023 12
Type 2 VMM
Hardware
VMM
GuestVM
GuestVM
GuestVM
Host OS
VMware Server
April 10, 2023 13
Hybrid VMM
MS Virtual ServerMS Virtual PC
Hardware
VMM
HostVM
GuestVM
GuestVM
April 10, 2023 14
Paravirtualisation
Paravirtualization is a virtualization technique that presents a software interface to virtual machines that is similar but not identical to that of the underlying hardware. This requires operating systems to be explicitly ported to run on top of the virtual machine monitor (VMM)
April 10, 2023 15
Full Virtualisation
• Provides a complete simulation of the underlying hardware
• With binary translation, rewrites some x86 instructions at run time that cannot be trapped and converts them into a series of instructions that can be trapped and virtualised
• Capable of running existing legacy operating systems without modification
April 10, 2023 16
Native Virtualisation
− Leverages hardware-assisted capabilities available in the latest processors from Intel (Intel VT – “Vanderpool”) and Advanced Micro Devices (AMD-V – “Pacifica”) to provide near-native performance.
− Virtual Iron is one of the first companies to offer virtualization software to fully support Intel-VT and AMD-V hardware assisted virtualization.
April 10, 2023 17
Native Virtualisation
− Dell• Precision 380 Intel Pentium D• PowerEdge 430 Intel Pentium D• PowerEdge 440 Intel Xeon 3xxx• PowerEdge 1435 AMD Opteron 22x• PowerEdge 1950 Intel Xeon 5xxx• PowerEdge 1955 Intel Xeon 5xxx• PowerEdge 2950 Intel Xeon 5xxx
− HP• ProLiant DL140 G3 Intel Xeon 5xxx • ProLiant DL320 G4 Intel Xeon 5xxx • ProLiant DL360 G5 Intel Xeon 5xxx • ProLiant DL365 AMD Opteron 22xx • ProLiant DL380 G5 Intel Xeon 5xxx • ProLiant DL385 G2 AMD Opteron 22xx • ProLiant DL580 G4 Intel Xeon 7xxx • ProLiant DL585 G2 AMD Opteron 82xx
− IBM• xSeries 100 Intel Pentium-D • System x3455 AMD Opteron 22xx• System x3550 Intel Xeon 5xxx • System x3850 Intel Xeon 7xxx HS21 Intel Xeon 5xxx • LS21 AMD Opteron 22xx
April 10, 2023 18
What’s in a Virtual Machine?
April 10, 2023 19
What’s in a Virtual Machine - BIOS
• VM has its own BIOS• Has everything you
would expect to see in a real BIOS
• Boot options may include floppy, CD-ROM, disk drive and PXE.
April 10, 2023 20
What’s in a Virtual Machine - Networking
• Each VM has a virtual NIC• Virtual NICs are connected
to virtual switches implemented in the virtualisation layer− VMware – vSwitches− Microsoft - .vnc-files
• Virtual switches have uplink connections to physical NICs on the host
April 10, 2023 21
Combining internal and external virtual switches
• Virtual switch with one outbound adapter acts as a DMZ
• Backend applications are secured behind the firewall using internal-only switches
April 10, 2023 22
What’s in a Virtual Machine - Storage
• To the applications and guest operating systems inside each virtual machine, the storage subsystem is a simple virtual SCSI host bus adapter connected to one or more virtual SCSI disks
• Virtual disks are files kept on physical storage.− VMware – VMDK files− Microsoft – VDF files
• Virtual disk represents a local drive on a virtual server, such as a C or D drive in Windows
• Physical storage could be− Direct attached SCSI− SAN attached− iSCSI− NAS
April 10, 2023 23
Licensing Considerations
• On host− Host OS?− Virtualisation technology?
• On Guest− Guest OS?− Guest Applications
April 10, 2023 24
Support Considerations
• Two meanings− Is it technically possible?− Will the vendor support a virtual environment?
• The Microsoft position− “For Microsoft customers who do not have a Premier-level support
agreement, Microsoft will require the issue to be reproduced independently from the non-Microsoft hardware virtualization software.”
− “Microsoft supports Windows Server System software running within a Microsoft Virtual Server environment subject to the Microsoft Support Lifecycle policy ... “ “
April 10, 2023 25
Usage Scenarios for Virtualization
Consolidation
Workload Mobility
Business Continuity Management
Development and Test
April 10, 2023 26
1. Logical
2. Physical
3. Rational
Gartner definition
Usage ScenarioProduction server consolidation
April 10, 2023 27
Usage ScenarioProduction server consolidation
• Consolidate workloads− Infrastructure applications− Low-utilization workloads− Branch office and datacenter workloads− Efficient use of available hardware resources
• Re-host legacy OS and applications− NT4 guest applications on virtual platform
• Run on current hardware and current OS• No application updates required
• Partition resources− Limit CPU resource per VM
April 10, 2023 28
Usage ScenarioBusiness continuity management
• Disaster Recovery− Maintain DR systems as virtual
machines− Eliminate traditional problems
associated with bare metal restores• OS and application patching
− Deploy and test patches off-production, and swap
− Eliminate scheduled downtime• Isolation / sandboxing
− Isolate OS environments for untrusted applications
− Prevent malicious code from affecting others
April 10, 2023 29
Usage ScenarioDynamic datacenter
• Workload mobility− Package up entire OS environment and move to
other location− Flexible deployment of workloads
April 10, 2023 30
Usage ScenarioDevelopment and test
• Rapid provisioning of virtual machines• Create arbitrary test scenarios• Wider test range for niche scenarios
April 10, 2023 31
Application + OS: Now A Data File
• Server provisioning is similar to copying a file
• Server migration is now similar to data migration
• Data management techniques can be used for server management
• Server cloning/copying• Versioning• Server archival• Remote mirroring
Entire server – OS, apps, data, devices, and state – is now simply a file.
April 10, 2023 32
The Role of Shared Storage
• Virtual Machine files are centrally located.
• Multiple access.• Virtual Machines can be
moved for DR purposes, system repair/upgrade, etc.
• Can take advantage of advanced SAN features such as snapshots, clones and replication.
April 10, 2023 33
Live Migration
• Move running virtual machines from one physical system to another with no downtime
• Zero downtime maintenance• Balance resource utilisation across infrastructure
April 10, 2023 34
Hardware Infrastructure – Scale Up or Scale Out?
• Scaling up means fewer, larger systems− Advantages
• Fewer ESX Server images to manage
• Lower infrastructure costs (Ethernet/SAN switches)
− Disadvantages• Higher hardware costs (servers)• Big H.A. impact in case of failure
of a node• Fewer CPUs supported "per rack“• Headroom required for HA is
expensive• Servers may go obsolete• Locked into server architecture
• Scaling out means more, smaller systems− Advantages
• Lower hardware costs (servers)
• Low H.A. impact in case of failure of a node
• More CPUs supported "per rack“
• Headroom required for HA is less expensive
• Not locked into obsolete hardware
• More flexible
− Disadvantages• Many hypervisor (ESX) images
to maintain• Higher infrastructure costs
(Ethernet/SAN switches)
April 10, 2023 35
What should an enterprise ready virtualisation platform offer?
• Efficient server partitioning• SMP support in guest VMs• Scalable memory in guest VMs• Fault isolation – a crash in one virtual machine should
not impact other virtual machines• Security isolation – a virtual machine should never
access the memory or I/O operations of another virtual machine
• Resource isolation – runaway applications in one virtual machine should not “starve” others virtual machines.
• Non-disruptive addition of capacity• Scalable management tools
April 10, 2023 36
VMware Workstation
• Desktop Virtualisation• Run multiple operating
systems simultaneously on a single PC
• Supports Windows, Linux, NetWare, Solaris
• Software development/test• Training
April 10, 2023 37
VMware Server
• Free virtualisation platform• Type 2 “hosted” VMM• Runs on any standard x86 hardware • Runs on a wide variety of Linux and
Windows host and guest operating systems
• Intended as a “step up” to Type 1 hypervisor products.
April 10, 2023 38
VMware Infrastructure 3
• VMware ESX Server 3.0 - Type 1 VMM
• VMware VirtualCenter 2.0• 4-way vSMP / 16GB Virtual RAM
support• VMware VMotion• VMware HA• VMware Distributed Resource
Scheduling• VMware Consolidated Backup
April 10, 2023 39
Non-disruptive capacity on demand
April 10, 2023 40
Automate resource assurance for critical applications
DRS Dynamic BalancingContinuous Optimization
April 10, 2023 41
Automatic availability for all applications
VMWARE HA
X
April 10, 2023 42
Backup anytime
VMWARECONSOLIDATEDBACKUP
Decouple backup from production VMs20-40% better resource utilizationPre-integrated with 3rd party backup products
April 10, 2023 43
Microsoft Virtualisation Products
• Virtual PC• Microsoft Virtual Server 2005 R2 • Virtual Machine Manager (in Beta but available
for download)• Windows Virtualisation (to be released after
Longhorn)
April 10, 2023 44
Virtual PC
• Suited to use in testing on a desktop environment
• Not recommended for production servers− Single CPU support only− No remote management possible− No SCSI support− Starts as an application not as a service
• Shares disk format with Virtual Server
April 10, 2023 45
Virtual Server 2005 R2 SP1
• Microsoft’s current offering for virtualisation in production environments
• Shares underlying technology with Microsoft Virtual PC
• Web based management portal
• Guests supported include:− Windows (up to Vista with
SP1)− Linux
Virtual Server 2005 R2: Administration Website
April 10, 2023 46
Clustering in Virtual Server 2005 R2 SP1
Host to Host
Cluster storage
SAN or iSCSI connection
Guest to Guest
Cluster storage
iSCSI connection
April 10, 2023 47
Virtual Server 2005 R2 SP1
• VM Additions− VM additions provide enhanced performance and
additional functionality to the guest OS− Additions available for XP, Windows 2003, Vista and
Linux− Windows additions provide:
• Allow for direct mode kernel execution (faster processing of some commands)
− Linux additions provide:• Time sync• Shutdown support• SCSI disk• Does not allow for direct mode kernel execution
− Important to update for each new release to maximise performance benefits
April 10, 2023 48
Windows Virtualisation
• To be released within 180 days after the Longhorn release (no Beta available as yet)
• Requires Intel VT or AMD Virtualisation hardware• Uses Hypervisor (a thin layer of software under
the “Host OS”)
Hardware
VMM (Hypervisor)
Guest 1(“Host OS”)
Guest 2
April 10, 2023 49
Virtual Machine Manager
Virtual Machine Manager: Centralized management view
April 10, 2023 50
Centralized Management: Reports
Full set of Full set of reports, reports,
integration with integration with MOM databaseMOM database
Actions one click Actions one click away in context away in context
sensitive Actions sensitive Actions PanePane
April 10, 2023 51
Self Service Portal
Ability to control Ability to control owned virtual owned virtual
machinesmachines
Thumbnails of Thumbnails of all owned virtual all owned virtual
machinesmachines
April 10, 2023 52
Self-Service PortalProvisioning
User selects from list User selects from list of templates of templates
Administrator has Administrator has associated with that associated with that
useruser
April 10, 2023 53
Self-Service PortalProvisioning
New virtual machine New virtual machine ready for use, Terminal ready for use, Terminal
Services connection Services connection information information
automatically emailed to automatically emailed to user.user.
April 10, 2023 54
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? 64 More than 64.As many as hardware will allow.
User interface Web Interface MMC 3.0 Interface
April 10, 2023 55
Xen
• Open source hypervisor solution
• Installs on bare-metal• Linux VMs fully supported
− Red Hat− Debian− Suse
• Windows VMs require Intel VT or AMD-V processor− Microsoft Windows Server
2000− Microsoft Windows Server
2003 − Microsoft Windows XP SP2
April 10, 2023 56
XenSource
April 10, 2023 57
XenSource Products
User Profile Enterprise IT, system integrators
Windows IT professionals
Developers, testers, support, IT enthusiasts
Windows guest support
Windows Server 2003; Windows XP; Windows 2000 Server
Windows Server 2003; Windows XP; Windows 2000 Server
Windows Server 2003; Windows XP; Windows 2000 Server
Linux guest support Red Hat EL 3.6, 3.7, 3.8, 4.1, 4.2, 4.3, 4.4, 5.0; SUSE SLES 9.2, 9.3, 10.1; Debian Sarge
N/A (Windows guests support only)
Red Hat EL 3.6, 3.7, 3.8, 4.1, 4.2, 4.3, 4.4, 5.0; SUSE SLES 9.2, 9.3, 10.1; Debian Sarge
Live Migration Mid-2007 N/A N/A
Shared storage Mid-2007 N/A N/A
April 10, 2023 58
Virtual Iron
• An enterprise ready native virtualisation platform
• Uses hardware-assisted virtualisation technologies of Intel VT and AMD-V processors
• Based on an open source hypervisor derived from the Xen open source project
• No software need be installed on physical hardware
April 10, 2023 59
Virtual Iron Components
Component License Function
Hypervisor GPL First software loaded when physical server boots. Manages all hardware resources
Service Partition
GPL Second software loaded when physical server boots. Manages virtual server creation and configuration and all I/O.
Virtualisation Manager
Commercial Controls virtual servers through an agent in the service partition
Guest operating systems
Varies Operating systems that are fully virtualised on a physical server
April 10, 2023 60
Virtualization Manager
• Java-based application
• Allows for central management of virtualized servers
• A physical server can have many virtualized servers, which are run as unmodified guest operating systems.
April 10, 2023 61
Virtual Manager Policy-based Automation
• LiveMigration – moves a running virtual server from one physical server without pausing or impacting running applications
• LiveCapacity – monitors virtual server CPU utilisation or other application needs to determine when a workload needs additional capacity. When a user-defined threshold is met, the virtual server is LiveMigrated to a physical server that has the necessary resources
• LiveRecovery – monitors the status of physical resources and moves virtual servers to maintain uptime in the event of a hardware failure
• LiveMaintenance – moves virtual servers to alternative locations without downtime when a physical server is taken offline for maintenance
April 10, 2023 62
Virtual Iron Architecture
April 10, 2023 63
Supported Configurations
Feature Support
Operating systems 32 and 64-bit Red Hat Enterprise Linux 432 and 64-bit SUSE Linux Enterprise Server 932-bit Windows XP32-bit Windows 2003
Processors Intel Xeon with Intel VTAMD Opteron with AMD-V
Virtualised Nodes 100s per virtual data centre
Processors per virtual Server Up to 8
RAM per Physical Server Up to 96GB
Virtual servers per physical server CPU Up to 5
Virtual NIC adapters per virtual server Up to 5
Virtual disks per virtual server Up to 16
April 10, 2023 64
Virtuozzo
− Operating System–Level Virtualisation
− Creates multiple, isolated virtual environments (VEs)
− Whereas VMs attempt to virtualize "a complete set of hardware," VEs represent a "lighter" abstraction, virtualizing instead "an operating system instance"
April 10, 2023 65
Parallels Workstation
• Test/Development solution aimed at desktop market
• Uses hypervisor technology
• Wide guest OS support− Entire Windows family - 3.1,
3.11, 95, 98, Me, 2000, XP and 2003
− Linux distributions Red Hat, SuSE, Mandriva, Debian and Fedora Core
− FreeBSD − “Legacy” operating systems
e.g. OS/2, eComStation and MS-DOS.
April 10, 2023 66
HP Virtual Server Environment
• Implemented on HP Integrity and HP 9000 systems
April 10, 2023 67
Physical to Virtual (P2V)
• P2V is the term used to describe the process of converting physical servers into virtual machines
• Can be performed while server is live• Some operating systems require cold migration• Process:
− Analyse source− Create a target VM− Transfer data from physical source to virtual target− Transform VM
April 10, 2023 68
VMware Converter
• Replaces P2V Assistant• Wizard based conversion
process• Can convert physical
machines, virtual machines or third party system images (e.g. Symantec Ghost, Backup Exec LiveState Recovery)
• Source physical machines:− 64-bit Windows XP/2003− WinNT SP4+− Windows 2000− Windows XP− Windows 2003
April 10, 2023 69
Platespin PowerConvert
• “Anywhere to anywhere” conversion− Peer-to-Peer
• Physical to Virtual (P2V)• Virtual to Virtual (V2V)• Virtual to Physical (V2P)• Physical to Physical (P2P)
− Image Capture• Physical to Image (P2I)• Virtual to Image (V2I)
− Image Deployment• Image to Virtual (I2V)• Image to Physical (I2P)
− Disaster Recovery• Physical to Virtual (P2V)• Virtual to Virtual (V2V)
• Windows and Linux sources can be converted
April 10, 2023 70
Platespin PowerConvert
April 10, 2023 71
Portlock Storage Manager
• Third-party NetWare data management product
• Can be used for P2V conversions of NetWare servers
• Requires some manual reconfiguration of VM
April 10, 2023 72
Capacity Planning
• Important first step in any server consolidation project
• Aims:− Understand server performance and utilization rates
of a group of servers− Identifying servers that are good candidates to be
migrated into virtual machines − Size virtual environment accurately
• Statistics are gathered and processed• What-if scenarios can be run to examine
different possible approaches
April 10, 2023 73
VMware Capacity Planner
April 10, 2023 74
Inventory AnalyseWorkload Data
Collection
Recommend
Platespin PowerRecon
• Onsite data collection and analysis• Scenario modelling (what-if)• Agentless operation
April 10, 2023 75
Some additional products…
April 10, 2023 76
VMware Lab Manager
• Create centralised pools of VMs, storage and network components
• Rapid setup and tear down of test/dev environments
• Maintain library of customer and production system environments
April 10, 2023 77
VMware ACE
April 10, 2023 78
VMware Virtual Desktop Infrastructure
April 10, 2023 79
Dunes VS-0
http://www.dunes.ch/content/view/82/157/
Dunes VS-O
April 10, 2023 80
− esxRanger Professional• LAN/WAN backups• Backup active servers• Database of backup activity
− esxReplicator• Replicate changes to remote
location – “chunked” by time or data change volumes
• Effective business continuity
Virtual Machine Backup and Replication
April 10, 2023 81
Virtual Machine Backup and Replication
• esXpress− Virtual Backup Appliance
runs backup jobs within a VM
− Offloads CPU and memory utilisation from VMware ESX console
• Virtual Solution Box− Also implemented as a
virtual machine appliance
April 10, 2023 82
esxCharter
A Windows based esxtop and more…
April 10, 2023 83
esxMigrator
• Assists customers upgrading from VMware ESX 2.X to VMware ESX 3.0
• Uses data manipulation strategies that can copy virtual disks much faster than allowed by the VMware console
• Enables failback contingency
April 10, 2023 84
Best Practice Recommendations
• Explore your options. • Evaluate your applications for potential
consolidation. • Understand the differences between various
virtualization solutions. • Look closely at the licensing and support
policies of your software vendors. • Start small.
April 10, 2023 85
Best Practice Recommendations
• Manage expectations. • Beware of “virtual sprawl.” • Consider blades as a complementary
consolidation strategy. • Integrate server consolidation with a broader
consolidation strategy. • Develop a framework for continuous
consolidation.