Virtualization is a method for abstracting physical resources from the way that they interact with other resources. For example, if you abstract the physical hardware from the operating system, you get the benefit of being able to move the operating system between different physical systems.

This is called server virtualization. But other forms of virtualization are available, such as presentation virtualization, desktop virtualization, and application virtualization. I will now briefly explain the differences between these forms of virtualization:

Server Virtualization This basically enables multiple servers to run on the same physical host server. Hyper- V is Microsoft’s server virtualization tool that allows you to turn physical machines into virtual machines and manage them on fewer physical servers. Thus, you will be able to consolidate physical servers. So, you can have less physical hardware but just as many individual servers that are needed to run your entire network. The individual machines that run on the host server are called virtual machines. Virtual machines are just guest servers that run on top of the Hyper-V  host server system.

Presentation Virtualization When you use presentation virtualization, your applications run on a different computer, and only the screen information is transferred to your computer. An example of presentation virtualization is Microsoft Remote Desktop  Services in Windows Server 2022.

Desktop Virtualization Desktop virtualization provides you with a virtual machine on your desktop, comparable to server virtualization. You run your complete operating system and applications in a virtual machine so that your local physical machine just needs to run a very basic operating system. An example of this form of virtualization is Microsoft Virtual PC.

Application Virtualization Application virtualization helps prevent conflicts between applications on the same PC. Thus, it helps you isolate the application running environment from the operating system installation requirements by creating application- specific copies of all shared resources. It also helps reduce application- to- application incompatibility and testing needs. An example of an application virtualization tool is Microsoft Application Virtualization (App- V).

When it comes to server virtualization, there are many different players in the game. The original king of virtualization is VMware. VMware was the first company to take server virtualization to the next level.

At the same time, Microsoft had smaller versions of virtualization such as Virtual Server. In 2008 Microsoft released its first version of Hyper- V. To say that Windows Server 2008 Hyper- V had flaws would be a kind way of putting it.

But as Microsoft continued to release versions of server, it kept improving Hyper- V. When Microsoft released Windows Server 2012 and 2012 R2, it made huge leaps and bounds. Then Windows Server 2016 and Server 2019 took Hyper- V to another level— a level where they could actually compete with VMware and other virtual vendors. The big advantage of Hyper- V is that it comes included with Windows Server.

So how do we get a Windows Server to allow multiple servers to all run on the same machine? Well, the great thing about virtualization is that it is all done for us using the Microsoft Windows Hypervisor.

The Windows hypervisor is a thin layer of software that sits between the hardware and the Windows Server 2022 operating system. This thin layer allows one physical machine to run multiple operating systems in different virtual machines at the same time. The hypervisor is the mechanism that is responsible for maintaining isolation between the different Hyper- V partitions.

The hypervisor allows the Hyper- V host server to have multiple virtual machines running on the same machine at one time. So now you may be wondering how many virtual machines you can run at the same time. This is all going to depend on your machine’s hardware and the licensing that you own. For example, physical memory and processors are

just two examples of hardware that would need to be increased depending on how many virtual machines you want to run. Also, other features loaded into the virtual environment may require even higher hardware demands like clustering. We will talk more about the hypervisor later in the chapter.

So since we are going to be focusing on Microsoft’s version of virtualization, let’s take a look at some of the Hyper- V features that you get.

Hyper- V Features

As a lead- in to the virtualization topic and Hyper- V, I will start with a list of key features, followed by a list of supported guest operating systems. This should provide you with a quick, high- level view of this feature before you dig deeper into the technology.

Key Features of Hyper- V

The following are the key features of Hyper- V:

Architecture The hypervisor- based architecture, which has a 64- bit micro- kernel, provides a new array of device support as well as performance and security improvements.

Automatic Virtual Machine Activation (AVMA) Automatic Virtual Machine Activation

(AVMA) is a feature that allows you to install virtual machines on a properly activated Windows Server 2022 system without the need to manage individual product keys for each virtual machine. When using AVMA, virtual machines get bound to the licensed Hyper- V server as soon as the virtual machine starts. The virtual machines can move the AVMA- licensed VM to other hosts, but the VM can only run one instance and it can only be on a host set up for AVMA. It is bound to the host it is running on, but it can move from host to host as long as the hosts are AVMA.

Discrete Device Assignment One feature of Windows Server 2022 is the ability to use Discrete Device Assignment (DDA). DDA allows you to take full advantage of performance and application compatibility improvements in the user experience by allowing the system’s graphic cards to be directly assigned to a virtual machine. This allows the graphic card processor to be fully available to the virtual desktops that are utilizing the native driver of the graphics card processor as well as the network card’s storage features.

Dynamic Memory Dynamic Memory is a feature of Hyper-V  that allows it to balance memory automatically among running virtual machines. Dynamic Memory allows Hyper- V to adjust the amount of memory available to the virtual machines in response to the needs of the virtual machines. It is currently available for Hyper-V  in Windows Server 2022.

Enhanced Session Mode Enhanced Session Mode enhances the interactive session of the Virtual Machine Connection for Hyper-V  administrators who want to connect to their virtual machines. It gives administrators the same functionality as a remote desktop connection when the administrator is interacting with a virtual machine.

In previous versions of Hyper- V, the virtual machine connection gave you limited functionality while you connected to the virtual machine screen, keyboard, and mouse. You could use an RDP connection to get full redirection abilities, but doing so would require a network connection to the virtual machine host. Enhanced Session Mode gives you the following benefits for local resource redirection:

                 ■         Display configuration

                 ^■         Audio

                 ^■         Printers

                 ^■         Clipboard

                 ^■         Smart cards

                 ^■        Drives

                 ^■        USB devices

                 ■         Supported Plug and Play devices

Fibre Channel The virtual Fibre Channel feature allows you to connect to the Fibre Channel storage unit from within the virtual machine. Virtual Fibre Channel allows you to use your existing Fibre Channel to support virtualized workloads. Hyper- V users have the ability to use Fibre Channel storage area networks (SANs) to virtualize the workloads that require direct access to SAN logical unit numbers (LUNs).

Hardware Architecture Hyper- V’s architecture provides improved utilization of resources such as networking, memory, and disks.

Hyper- V Nesting Windows Server 2022 has a feature of Hyper- V called Hyper- V  nesting. Hyper- V nesting allows you to run a virtual machine in a virtual machine. So, let’s say that you build a new 2016 Hyper-V  server. You install Windows Server 2022 into a virtual machine. Then in that virtual machine, you can install Hyper-V  and build other virtual machines within the first virtual machine. You can install a  Windows Server 2022 virtual machine and still show others how to install and create virtual machines in the original virtual machine. To enable Hyper- V nesting, you would run the following PowerShell command on the Hyper-V  Host. The virtual machines must be in the OFF State when this command is run (this means the virtual machines must be turned off).

Set- VMProcessor – VMName <VMName> -E xposeVirtualizationExtensions $true

Network Isolation One nice feature of using Microsoft Hyper-V  network virtualization is the ability of Hyper- V to keep virtual networks isolated from the physical network infrastructure of the hosted system. Because you can set up Hyper-V  software– defined virtualization policies, you are no longer limited by the IP address assignment or VLAN isolation requirements of the physical network. Hyper-V  allows for built- in network isolation to keep the virtual network separated from the virtual network.

Network Load Balancing Hyper- V provides support for Windows Network Load Balancing (NLB) to balance the network load across virtual machines on different servers.

Non- Uniform Memory Access Non- Uniform Memory Access (NUMA) is a multiprocessor memory architecture that allows a processor to access its local memory quicker than memory located on another processor. NUMA allows a system to access memory quickly by providing separate memory on each processor. Processors can access their local assigned memory, thus speeding the system performance. Normally a multiprocessor system runs into performance issues when multiple processors access the same memory at the same time. NUMA helps prevent this by allowing processors to access their own memory. Memory that is dedicated to a processor is referred to as a

NUMA node.

Operating System Support Both 32- bit and 64- bit operating systems can run simultaneously in Hyper- V. Also, different platforms like Windows, Linux, and others are supported.

Quick Migration Hyper- V’s quick migration feature provides you with the functionality to run virtual machines in a clustered environment with switchover capabilities when there is a failure. Thus, you can reduce downtime and achieve higher availability of your virtual machines.

Resource Metering Hyper- V resource metering allows your organization to track usage within the businesses departments. It allows you to create a usage- based billing solution that adjusts to your provider’s business model and strategy.

RemoteFX Windows Server 2022 Hyper-V  RemoteFX allows for an enhanced user experience for RemoteFX desktops by providing a 3D virtual adapter, intelligent codecs, and the ability to redirect USB devices in virtual machines.

Scripting Using the Windows Management Instrumentation (WMI) interfaces and APIs, you can easily build custom scripts to automate processes in your virtual machines.

Shared Virtual Hard Disk Windows Server 2022 Hyper-V  has a feature called Shared Virtual Hard Disk. Shared Virtual Hard Disk allows you to cluster virtual machines by using shared virtual hard disk (VHDX) files.

Shared virtual hard disks allow you to build a high availability infrastructure, which is important if you are setting up either a private cloud deployment or a cloud-h osted environment for managing large workloads. Shared virtual hard disks allow two or more virtual machines to access the same VHDX file.

Shielded Virtual Machines Shielded Virtual Machines are a generation 2 virtual machine that uses a virtual Trusted Platform Module chip and is encrypted using  Windows BitLocker. Shielded Virtual Machines allow enterprise administrators to  provide a more secure environment for their tenant virtual machines.

Support for Symmetric Multiprocessors Support for up to 64 processors in a virtual machine environment provides you with the ability to run applications as well as multiple virtual machines faster.

Virtual Machines Virtual machines are the operating systems that run on the virtual server. They can be full operating systems or smaller versions of operating systems. The virtual machines are the actual virtual environment that these operating systems run in. They can communicate and operate on a network the same way a physical server can.

Virtual Machine Snapshot You can take snapshots of running virtual machines, which provides you with the capability to recover to any previous virtual machine snapshot state quickly and easily.

Virtual Machine Queue Windows Server 2022 Hyper-V  includes a feature called Virtual Machine Queue (VMQ) as long as the hardware is VMQ-c ompatible network hardware. VMQ uses packet filtering to provide data from an external virtual machine network directly to virtual machines. This helps reduce the overhead of routing packets from the management operating system to the virtual machine.

Once VMQ is enabled on Hyper- V, a dedicated queue is created on the physical network adapter for each virtual network adapter to use. When data arrives for the virtual network adapter, the physical network adapter places that data in a queue and once the system is available, all the data in the queue is delivered to the virtual network adapter.

To enable the virtual machine queue on a specific virtual machine, enter the settings for the virtual machine and expand Network Adapter. Click Hardware Acceleration in the right window; then select Enable Virtual Machine Queue.