- What Is Server Virtualization and Microsoft Hyper-V?
- Choosing to Virtualize Servers
- Understanding Microsoft's Virtualization Strategy
- What's New in Hyper-V
- Determining What Is Needed to Virtualize Servers
- The Right Time to Implement Hyper-V
- Migrating from Microsoft Virtual Server 2005 and VMware
- Understanding the Administration of Virtual Guest Sessions
- Ensuring High Availability of a Hyper-V Host Server
- Best Practices
Determining What Is Needed to Virtualize Servers
Hyper-V is supported on both the host server side and the guest image side. Hyper-V runs on a Windows Server 2008 system, but not all versions of Windows 2008 allow installation of the Hyper-V role. Likewise, Microsoft does not support all operating systems as guest images. So, you want to ensure that both host and guest images are supported. This section covers what is needed to support virtual hosts and guest sessions.
Versions of Windows Server 2008 That Host Hyper-V
Windows 2008 comes in several versions: Web Server, Standard, Enterprise, and Datacenter. It also comes in a version called Server Core, which is a version of Windows 2008 that provides a lighter, GUI-less version of Windows 2008. Hyper-V runs only on the Standard, Enterprise, and Datacenter versions of Windows 2008 (not on Web Server), and it runs only on the x64-bit version of Windows.
From a licensing standpoint, Microsoft allows organizations to purchase and use Windows 2008 at a lower cost with a version of Windows 2008 x64-bit that does not support Hyper-V. This version is more likely purchased by an organization using a virtualization product from a third-party vendor and not planning to use the Hyper-V capabilities.
Windows Server 2008 x64-bit, Enterprise Edition
Windows Server 2008 x64-bit Enterprise Edition is the most common version of Windows purchased for a Hyper-V host server for virtualization. The x64-bit version is needed to support both 32-bit and 64-bit guest sessions and provides the ability to support up to 2TB of RAM.
Microsoft is licensing the Enterprise Edition of Windows 2008 in a manner that allows an organization to run up to four guest sessions on the server without the need to purchase additional Windows server licenses. So effectively, an organization can purchase one Enterprise Edition of Windows 2008 and run four Windows 2008 Enterprise Edition guest sessions for free.
As an Enterprise Windows 2008 server, the host system and any of the Enterprise guest sessions are capable of extremely large-scale processing and memory functions, clustering, and Active Directory Federation Services.
The Enterprise Edition, with support for server clustering, can provide organizations with true 24×7, 99.999% uptime capabilities required in high-availability environments. Windows Server 2008, Enterprise Edition supports a wide variety of regularly available server systems, thus allowing an organization its choice of hardware vendor systems to host its Windows 2008 application needs.
Windows Server 2008 x64-bit, Standard Edition
While the Windows Server 2008, Standard Edition is a common server version of the operating system for basic server functions (domain controllers, DNS servers, DHCP servers, and the like), and while the x64-bit version of the Standard Edition of Windows 2008 supports Hyper-V virtualization, most organizations still purchase the Enterprise Edition of Windows 2008 for their Hyper-V hosts. They do so because the Standard Edition of Windows 2008 provides licensing support for the host server plus one additional guest session. Each guest session beyond the first session requires the organization to buy additional server licenses. By the time the organization adds two or three guest sessions to a Standard Edition host, the organization would have been better off buying the Enterprise Edition host and run up to four additional sessions at no additional cost.
The Standard Edition of Windows 2008 x64-bit provides support for up to 32GB of memory, which is plenty of memory to run several guest sessions within the 32GB host limit. The Standard Edition of Windows is a good version of the operating system to support domain controllers, utility servers (such as DNS or DHCP), file servers, print servers, media servers, SharePoint servers, Network Policy and Access Services systems, and so on. Most organizations, large and small, find the capabilities of the Standard Edition sufficient for most network services.
Windows Server 2008, Datacenter Edition
Windows Server 2008, Datacenter Edition is a high-end hardware version of the operating system that supports very large-scale data center operations. The Datacenter Edition supports organizations that need more than 16-way symmetric multiprocessing, or memory up to 2TB, or clustering beyond 8 nodes. The Datacenter Edition is focused at organizations that need scale-up server technology to support a large centralized data warehouse on one or limited numbers of server clusters.
Based on Microsoft's licensing of the Datacenter Edition, an organization that properly licenses Datacenter based on the number of processors of the Datacenter host server has the right to install an unlimited number of guest sessions at no additional cost for Windows server licensing for the guest sessions.
As noted in Chapter 7, "Optimizing the Hyper-V Host Server and Guest Sessions," on performance and capacity analysis, an organization can scale out or scale up its server applications. Scale out refers to an application that performs better when it is distributed across multiple servers, whereas scale up refers to an application that performs better when more processors are added to a single system. Typical scale-out applications include web server services, electronic messaging systems, and file and print servers. In those cases, organizations are better off distributing the application server functions to multiple Windows Server 2008, Standard Edition or Enterprise Edition systems. However, applications that scale up, such as e-commerce, data warehousing applications, or potentially server virtualization, benefit from having all the data and processing on a single server cluster. For these applications, Windows Server 2008, Datacenter Edition provides better centralized scaled performance and the added benefit of fault tolerance and failover capabilities.
Windows Server 2008 Server Core
New to Windows 2008 is a Server Core version of the operating system. Windows 2008 Server Core, shown in Figure 1.6, is a GUI-less version of the Windows 2008 operating system. When a system boots with Server Core installed on it, the system does not load the normal Windows GUI. Instead, the Server Core system boots to a logon prompt, and from the logon prompt the system drops to a DOS command prompt. There is no Start button, no menu, no GUI at all.
Figure 1.6 Windows 2008 Server Core.
Server Core is not sold as a separate edition, but rather as an install option that comes with the Standard, Enterprise, Datacenter, and Web Server editions of the operating system. So, when you purchase a license of Windows Server 2008, Enterprise Edition, for example, the DVD has both the normal Enterprise Edition code plus a Windows 2008 Enterprise Edition Server Core version.
The operating system capabilities are limited to the edition of Server Core being installed, so a Windows Server 2008, Enterprise Edition Server Core server has the same memory and processor limits as the regular Enterprise Edition of Windows 2008.
Server Core has proven to be a great version of Windows for utility servers such as domain controllers, DHCP servers, DNS servers, and IIS web servers. The limited overhead provides more resources to the applications running on the server, and by removing the GUI and associated applications, there's less of a security attack footprint on the Server Core system. Because most administrators don't play Solitaire or use Media Player on a domain controller, those applications don't need to be patched, updated, or maintained on the GUI-less version of Windows. With fewer applications to be patched, the system requires less maintenance and management to remain operational.
With the lighter "footprint," Server Core has proven to be an excellent edition of Windows to run Hyper-V host services. The Hyper-V host can be centrally administered from a different server or workstation, and all the guest sessions are virtually managed and administered anyway. So, minimizing the attack surface and administration surface of a host server using Server Core has proven to make a lot of sense. Chapter 4, "Installing Windows 2008 Server and the Hyper-V Role," covers how to install the Server Core and how to install the Hyper-V application from a command prompt of the Server Core host system.
Versions of Guest Sessions Supported Under Hyper-V
Microsoft has specific support for certain versions of operating systems as guest sessions within Hyper-V. Although you can effectively boot and try to install any operating system on Hyper-V and can frequently get to the point where the operating system will work under Hyper-V, Microsoft officially supports only specific versions of operating systems as guest sessions.
Windows Server 2008 x86 and x64
Microsoft provides full support for running the Web Server, Standard, and Enterprise editions of Windows Server 2008 as a guest session under Hyper-V. In addition, the support extends to both the 32-bit x86 version and the 64-bit x64 versions of the Windows Server software. A guest session has the same limitation as the operating system has in running on a physical server. So, a 32-bit version of Windows 2008 Standard Edition will support a maximum of 4GB of RAM, whereas an Enterprise Edition of x86 will support up to 32GB of RAM, and the x64-bit version of Windows 2008 Enterprise will support the maximum amount of memory available in the host server.
In addition, symmetrical multiprocessing support (SMP) is limited to the maximum capability of the operating system being installed. So, support for one-, two-, or four-way SMP for each guest session up to the available number of processors in the host system is available for guest sharing.
Specific support for Windows 2008 guest sessions are as follows:
Microsoft Windows Server 2008 x64 (VMs configured with 1, 2, or 4 virtual processors)
- Windows Server 2008 Standard
- Windows Server 2008 Enterprise
- Windows Server 2008 Datacenter
- Windows HPC Server 2008
- Windows Web Server 2008
- Windows Server 2008 Standard without Hyper-V
- Windows Server 2008 Enterprise without Hyper-V
- Windows Server 2008 Datacenter without Hyper-V
Microsoft Windows Server 2008 x86 (VMs configured with 1, 2, or 4 virtual processors)
- Windows Server 2008 Standard (x86 Edition)
- Windows Server 2008 Enterprise (x86 Edition)
- Windows Server 2008 Datacenter (x86 Edition)
- Windows Web Server 2008 (x86 Edition)
- Windows Server 2008 Standard without Hyper-V (x86 Edition)
- Windows Server 2008 Enterprise without Hyper-V (x86 Edition)
- Windows Server 2008 Datacenter without Hyper-V (x86 Edition)
Windows Server 2003 x86 and x64
Windows Server 2003 guest sessions are also supported for Service Pack 2 and later. As with Windows 2008 guest sessions, the guest sessions of Windows Server 2003 are limited to the maximum support for the core Windows 2003 operating system itself, or in some cases less than the maximum support of the core operating system itself.
As a Hyper-V guest session, Windows 2003 x86 and Windows 2003 x64-bit support up to two-way SMP. The specific support is as follows:
Microsoft Windows Server 2003 x86 (VMs configured with 1 or 2 virtual processors)
- Windows Server 2003 R2 Standard x86 Edition with Service Pack 2
- Windows Server 2003 R2 Enterprise x86 Edition with Service Pack 2
- Windows Server 2003 R2 Datacenter x86 Edition with Service Pack 2
- Windows Server 2003 Standard x86 Edition with Service Pack 2
- Windows Server 2003 Enterprise x86 Edition with Service Pack 2
- Windows Server 2003 Datacenter x86 Edition with Service Pack 2
- Windows Server 2003 Web Edition with Service Pack 2
Microsoft Windows Server 2003 x64 (VMs configured with 1 or 2 virtual processors)
- Windows Server 2003 R2 Standard x64 Edition with Service Pack 2
- Windows Server 2003 R2 Enterprise x64 Edition with Service Pack 2
- Windows Server 2003 R2 Datacenter x64 Edition with Service Pack 2
- Windows Server 2003 Standard x64 Edition with Service Pack 2
- Windows Server 2003 Enterprise x64 Edition with Service Pack 2
- Windows Server 2003 Datacenter x64 Edition with Service Pack 2
Windows 2000 Server SP4
Microsoft also released Hyper-V to support Windows 2000 Server guest sessions for organizations that need to support a guest session with an older server operating system. Both Windows 2000 Server and Windows 2000 Advanced Server editions are supported. The specific support is as follows:
Microsoft Windows 2000 Server (VMs configured with 1 virtual processor)
- Windows 2000 Server with Service Pack 4
- Windows 2000 Advanced Server with Service Pack 4
Windows Vista x86 and x64-bit
Windows Vista is supported with Service Pack 1 in both the 32-bit and x64-bit versions of Vista and with support for one or two processors per guest session. Hyper-V supports a broad range of support for Windows Vista guest sessions for an administrator to install a guest session on the host server for application testing or to simulate user-access host services from within Hyper-V.
Specific support for Windows Vista is as follows:
Microsoft Windows Vista x86 (VMs configured with 1 or 2 virtual processors)
- Windows Vista Business x86 with Service Pack 1
- Windows Vista Enterprise x86 with Service Pack 1
- Windows Vista Ultimate x86 with Service Pack 1
Microsoft Windows Vista x64 (VMs configured with 1 or 2 virtual processors)
- Windows Vista Business x64 with Service Pack 1
- Windows Vista Enterprise x64 with Service Pack 1
- Windows Vista Ultimate x64 with Service Pack 1
Windows XP x86 and x64-bit
Similarly, Windows XP is rarely installed on a Hyper-V system for anything more than to test applications running in guest sessions on the Hyper-V host server. Windows XP with Service Pack 2 and Service Pack 3 are supported, with the ability to support one (SP2 or SP3) or two processors (SP3) for the guest session.
The specific support for a guest session running Windows XP is as follows:
Microsoft Windows XP Professional x86
- Windows XP Professional x86 with Service Pack 3 (VMs configured with 1 or 2 virtual processors)
- Windows XP Professional x86 with Service Pack 2 (VMs configured with 1 virtual processor)
Microsoft Windows XP Professional x64 (VMs configured with 1 or 2 virtual processors)
- Windows XP Professional x64 with Service Pack 2
SUSE Linux Enterprise Server 10 x86 and x64
Because of its partnership with Novell, Microsoft came out with support for SUSE Linux Enterprise Server running Service Pack 1 or Service Pack 2 (the first Linux operating system to receive such support). A SUSE Linux session can support one processor and up to the maximum amount of RAM memory supported by the x86 or the x64 versions of the operating system.
The support for Linux as a guest session under Hyper-V is as follows:
Linux Distributions (VMs configured with 1 virtual processor)
- Suse Linux Enterprise Server 10 with Service Pack 2 x86 Edition
- Suse Linux Enterprise Server 10 with Service Pack 2 x64 Edition
- Suse Linux Enterprise Server 10 with Service Pack 1 x86 Edition
- Suse Linux Enterprise Server 10 with Service Pack 1 x64 Edition
Guest Session Integration Support Tools
Key to the support of a guest operating system is not just whether Microsoft officially supports the guest operating system under Hyper-V, but also whether the integration support tools are available for the given operating system. This is where the version of operating system is critical. If you install Windows 2003 SP1 and want to install the Windows 2003 integration support tools, for instance, you will get an error saying that the integration tools will install only on Windows 2003 with Service Pack 2 installed.
The integration support tools have key network drivers, sound drivers, disk drivers, and the like optimized to support a guest session within Windows 2008 Hyper-V. The integration support tools also enable seamless use of the mouse and keyboard between host and guest that allows the administrator to simply switch between administering the host and the guest sessions. If the guest session doesn't have the integration tools installed, however, the administrator must "release" the keyboard and mouse from a guest session before the host has access and control of the keyboard and mouse on the system.
The integration support tools are installed on the host system when the Hyper-V role is installed on the host. The integration support tools can be installed onto the guest sessions, as shown in Figure 1.7, from within the Hyper-V Administration tool. You can find more information about the Hyper-V integration support tools in Chapter 5.
Figure 1.7 Hyper-V integration support tools add-in.