VIRTUAL MACHINE

IMPLEMENTATION

"The concept of the virtual machine is one of the most important concepts in computer science today. Emulators use virtual machines, operating systems use virtual machines (Microsoft's .NET), and programming languages use virtual machines (Perl, Java)". Read on for his review of Virtual Machine Design and Implementation in C/C++, an attempt to examine and explain virtual machines and the concepts which allow them to exist.

Virtual machines are, in effect, a software model of a whole system architecture and processor. They take in bytecode (formed of opcodes, operands, and other data) and execute it, much in the same way a real system executes code. Running these operations in software, however, gives you more security, and total control over how the system works.

Virtual machines are popular for a number of reasons. The first is that they give programmers a third compiler option. You don't have to either go the dynamic interpreted route or the static compiled route, you can compile for a virtual machine instead. Another is that virtual machines aid portability. If you compile your code for a virtual machine, you can run that binary on any system to which the virtual machine has been ported.

Few books have been written on virtual machines, with only a few Java Virtual Machine titles available. Virtual Machine Design and Implementation by Bill Blunden is therefore a landmark book for anyone with an interest in virtual machines, or even system and processor architecture as a whole.

BENEFITS

Top Ten Benefits 2008

The latest version of System Center Virtual Machine Manager incorporates all the functionality of its predecessor and brings exciting new capabilities to the management of virtual machines. Here are 10 of the most valuable benefits that Virtual Machine Manager 2008 (VMM) can provide to your organization.

- Designed for virtual machines running on Windows Server 2008 and Microsoft Hyper-V Server

Hyper-V is the next-generation hypervisor-based virtualization platform from Microsoft, which is designed to offer high performance, enhanced security, high availability, scalability, and many other improvements. VMM is designed to take full advantage of these foundational benefits through a powerful yet easy-to-use console that streamlines many of the tasks necessary to manage virtualized infrastructure. Even better, administrators can manage their traditional physical servers right alongside their virtual resources through one unified console.

- Support for Microsoft Virtual Server and VMware ESX

With this release, VMM now manages VMware ESX virtualized infrastructure in conjunction with the Virtual Center product. Now administrators running multiple virtualization platforms can rely on one tool to manage virtually everything. With its compatibility with VMware VI3 (through Virtual Center), VMM now supports features such as VMotion and can also provide VMM-specific features like Intelligent Placement to VMware servers.

- Performance and Resource Optimization (PRO)

Performance and Resource Optimization (PRO) enables the dynamic management of virtual resources though Management Packs that are PRO enabled. Utilizing the deep monitoring capabilities of System Center Operations Manager 2007, PRO enables administrators to establish remedial actions for VMM to execute if poor performance or pending hardware failures are identified in hardware, operating systems, or applications. As an open and extensible platform, PRO encourages partners to design custom management packs that promote compatibility of their products and solutions with PRO’s powerful management capabilities.

- Maximize datacenter resources through consolidation

A typical physical server in the datacenter operates at only 5 to 15 percent CPU capacity. VMM can assess and then consolidate suitable server workloads onto virtual machine host infrastructure, thus freeing up physical resources for repurposing or hardware retirement. Through physical server consolidation, continued datacenter growth is less constrained by space, electrical, and cooling requirements.

- Machine conversions are a snap!

Converting a physical machine to a virtual one can be a daunting undertaking—slow, problematic, and typically requiring you to halt the physical server. But thanks to the enhanced P2V conversion in VMM, P2V conversions will become routine. Similarly, VMM also provides a straightforward wizard that can convert VMware virtual machines to VHDs through an easy and speedy Virtual-to-Virtual (V2V) transfer process.

- Quick provisioning of new machines

In response to new server requests, a truly agile IT department delivers new servers to its business clients anywhere in the network infrastructure with a very quick turnaround. VMM enables this agility by providing IT administrators with the ability to deploy virtual machines in a fraction of the time it would take to deploy a physical server. Through one console, VMM allows administrators to manage and monitor virtual machines and hosts to ensure they are meeting the needs of the corresponding business groups.

- Intelligent Placement minimizes virtual machine guesswork in deployment

VMM does extensive data analysis on a number of factors before recommending which physical server should host a given virtual workload. This is especially critical when administrators are determining how to place several virtual workloads on the same host machine. With access to historical data—provided by Operations Manager 2007—the Intelligent Placement process is able to factor in past performance characteristics to ensure the best possible match between the virtual machine and its host hardware.

- Delegated virtual machine management for Development and Test

Virtual infrastructures are commonly used in Test and Development environments, where there is constant provisioning and tear down of virtual machines for testing purposes. This latest version of VMM features a thoroughly reworked and improved self-service Web portal, through which administrators can delegate this provisioning role to authorized users while maintaining precise control over the management of virtual machines.

- The library helps keep virtual machine components organized

To keep a data center’s virtual house in order, VMM provides a centralized library to store various virtual machine “building blocks”—off-line machines and other virtualization components. With the library’s easy-to-use structured format, IT administrators can quickly find and reuse specific components, thus remaining highly productive and responsive to new server requests and modifications.

- Windows PowerShell provides rich management and scripting environment

The entire VMM application is built on the command-line and scripting environment, Windows PowerShell. This version of VMM adds additional PowerShell commandlets and “view script” controls, which allow administrators to exploit customizing or automating operations at an unprecedented level.

EXAMPLE

In figure 92 is an example of an explicitly authorized TSAF collection involving two z/VM systems sharing global resources. The entries within each box represent the CP directory entries for each CMS virtual machine.

Figure 92. TSAF Collection with Authorized Global Resource Managers and User Programs

In figure 92, users have the following authorization:

-USERa on VMSYS1 can connect only to RES2 on VMSYS2.
-USERb on VMSYS1 can connect only to RES1 on VMSYS1.
-USERc on VMSYS2 can connect to RES1 on VMSYS1 and to RES2 on VMSYS2.
-USERd on VMSYS2 can connect only to RES2 on VMSYS2.