Key Concepts: Creating Virtual Machines in VMM

Article
04/29/2011

Applies To: Virtual Machine Manager 2008, Virtual Machine Manager 2008 R2, Virtual Machine Manager 2008 R2 SP1

When you begin creating virtual machines in System Center Virtual Machine Manager (VMM), you need to understand the following concepts.

Term	Definition
virtual machine	Essentially a computer within a computer, implemented in software. A virtual machine emulates a complete hardware system, from processor to network card, in a self-contained, isolated software environment, enabling the simultaneous operation of otherwise incompatible operating systems. Each operating system runs in its own isolated software partition.
virtual machine host	A physical computer that hosts one or more virtual machines. Also known as a “host.”
guest operating system	The operating system running on a virtual machine.
virtualization guest services	Generic term for software drivers that maximize performance of virtual machines on the virtualization software. Examples include Virtual Guest Services on Hyper-V, Virtual Machine Additions on Virtual Server, and on VMware Tools on VMware.
Integration Components	For Hyper-V, software drivers that maximize performance and provide a better user interface (UI) experience within a virtual machine.
Virtual Machine Additions	For Virtual Server and Virtual PC, software drivers that maximize performance and provide a better user interface (UI) experience within a virtual machine. Virtual Machine Additions are available only for supported guest operating systems.
VMware Tools	For VMware, software drivers that maximize performance and provide a better user interface (UI) experience within a virtual machine.
virtual machine placement	The process of selecting the most suitable host to deploy a virtual machine on. Also known as “placement.” During placement, hosts are rated based on the virtual machine’s hardware and resource requirements and the anticipated usage of resources. Host ratings also take into consideration the placement goal: either resource maximization on individual hosts or load balancing among hosts.
host rating	A rating, consisting of zero through five stars, that is assigned to each host during virtual machine placement to indicate the host’s suitability for hosting the virtual machine. The host rating is based on the virtual machine's hardware and software requirements and anticipated resource usage. Host ratings also take into consideration the placement goal: either resource maximization on hosts or load balancing among hosts. The metrics for rating hosts can be customized for Virtual Machine Manager and for individual virtual machines during placement.
virtual machine template	A library resource consisting of a guest operating system profile, a hardware profile, and one or more virtual hard disks (.vhd files), which can be used to create a new virtual machine. Computer identify information must have been removed from the .vhd file that contains the operating system files by using the System Preparation tool (Sysprep.exe). Self-service users must use designated templates to create their virtual machines.
hardware profile	A library resource containing hardware specifications that can be applied to a new virtual machine or a virtual machine template. A hardware profile can contain specifications for CPU, memory, network adapters, a DVD drive, a floppy drive, COM ports, and the priority given the virtual machine when allocating resources on a virtual machine host.
guest operating system profile	A library resource containing the most common settings from a Sysprep.inf file, including the computer name and domain or workgroup settings, which can be applied to a virtual machine template.
virtual hard disk	A file, referred to as a .vhd file, which provides storage for a virtual machine. The .vhd file can reside on any storage topology that the host operating system can access, including external devices, storage area networks, and network-attached storage. For managed VMware environments, the file name extension for a virtual hard disk is .vmdk.
virtual floppy disk	A file-based version of a physical floppy disk. A virtual floppy disk has a .vfd file name extension. For managed VMware environments, the file name extension for a virtual floppy disk is .flp.
virtual DVD	Configuration settings that represent a physical DVD drive for use in a virtual machine.
virtual network	An emulation of a physical network. A virtual network can be configured to provide access to local or external network resources for one or more virtual machines. A virtual network includes a virtual DHCP server that can provide virtual Internet Protocol (IP) address leases to virtual machines only.