Windows Server 2012 : A complete virtualization platform (part 1) - Hyper-V extensible switch - Configuring virtual switches

Virtualization can bring many benefits for businesses, including increased agility, greater flexibility, and improved cost efficiency. Combining virtualization with the infrastructure and tools needed to provision cloud applications and services brings even greater benefits for organizations that need to adapt and scale their infrastructure to meet the changing demands of today’s business environment. With its numerous improvements, Hyper-V in Windows Server 2012 provide the foundation for building private clouds that can use the benefits of cloud computing across the business units and geographical locations that typically make up today’s enterprises. By using Windows Server 2012, you can begin transitioning your organization’s datacenter environment toward an infrastructure as a service (IaaS) private cloud that can provide your business units with the “server instances on demand” capability that they need to be able to grow and respond to changing market conditions.

Hosting providers also can use Windows Server 2012 to build multi-tenant cloud infrastructures (both public and shared private clouds) that they can use to deliver cloud-based applications and services to customers. Features and tools included in Windows Server 2012 enable hosting providers to fully isolate customer networks from one another, deliver support for service level agreements (SLAs), and enable chargebacks for implementing usage-based customer billing.

Let’s dig into these features and capabilities in more detail. We’ll also get some insider perspective from experts working at Microsoft who have developed, tested, deployed, and supported Windows Server 2012 during the early stages of the product release cycle.

The new Hyper-V extensible switch in Windows Server 2012 is key to enabling the creation of secure cloud environments that support the isolation of multiple tenants. The Hyper-V extensible switch in Windows Server 2012 introduces a number of new and enhanced capabilities for tenant isolation, traffic shaping, protection against malicious virtual machines, and hassle-free troubleshooting. The extensible switch allows third parties to develop plug-in extensions to emulate the full capabilities of hardware-based switches and support more complex virtual environments and solutions.

Previous versions of Hyper-V allowed you to implement complex virtual network environments by creating virtual network switches that worked like physical layer-2 Ethernet switches. You could create external virtual networks to provide VMs with connectivity with externally located servers and clients, internal networks to allow VMs on the same host to communicate with each other as well as the host, or private virtual networks (PVLANs) that you can use to completely isolate all VMs on the same host from each other and allow them to communicate only via external networks.

The Hyper-V extensible switch facilitates the creation of virtual networks that can be implemented in various ways to provide great flexibility in how you can design your virtualized infrastructure. For example, you can configure a guest operating system within a VM to have a single virtual network adapter associated with a specific extensible switch or multiple virtual network adapters (each associated with a different switch), but you can’t connect the same switch to multiple network adapters.

What’s new however is that the Hyper-V virtual switch is now extensible in a couple of different ways. First, you can now install custom Network Driver Interface Specification (NDIS) filter drivers (called extensions) into the driver stack of the virtual switch. For example, you could create an extension that captures, filters, or forwards packets to extensible switch ports. Specifically, the extensible switch allows for using the following kinds of extensions:

Second, you can use the capabilities of the Windows Filtering Platform (WFP) by using the built-in Wfplwfs.sys filtering extension to intercept packets as they travel along the data path of the extensible switch. You might use this approach, for example, to perform packet inspection within your virtualized environment.

These different extensibility capabilities of the Hyper-V extensible switch are intended primarily for Microsoft partners and independent software vendors (ISVs) so they can update their existing network monitoring, management, and security software products so they can work not just with physical hosts, but also with VMs deployed within any kind of virtual networking environment that you might possibly create using Hyper-V in Windows Server 2012. In addition, being able to extend the functionality of the Hyper-V networking by adding extensions makes it easier to add new networking functionality to Hyper-V without needing to replace or upgrade the switch. You’ll also be able to use the same tools for managing these extensions that you use for managing other aspects of Hyper-V networking, namely the Hyper-V Manager console, PowerShell, and Windows Management Instrumentation (WMI). And because these extensions integrate into the existing framework of Hyper-V networking, they automatically work with other capabilities, like Live Migration.

Table 1 summarizes some of the benefits of the Hyper-V extensible switch from both the IT professional and ISV perspective.

1.1 Configuring virtual switches

Figure 1 shows the Windows Filtering Platform (WPF) extension selected in the Virtual Switch Manager of the Hyper-V Console in the beta version of Windows Server 2012. Note that once extensions are installed on the host, they can be enabled or disabled and also have their order rearranged by moving them up or down in the list of switch extensions.

Figure 1. Virtual switch extensions for the Hyper-V extensible switch.

You can also use PowerShell to create, delete, and configure extensible switches on Hyper-V hosts. For example, Figure 2 shows how to use the Get-VMSwitchExtension cmdlet to display details concerning the extensions installed on a specific switch.

Figure 2. Displaying all extensions installed on the virtual switch named CONTOSO.

You also can display the full list of PowerShell cmdlets for managing the extensible switch, as Figure 3 illustrates.

Figure 3. Displaying all PowerShell cmdlets for managing virtual switches.