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Chapter 2. Virtual Machines
This chapter provides an overview of how to create Virtual Machines (VMs) using templates. It also explains other
preparation methods, including physical to virtual conversion (P2V), cloning templates, and importing previously-
exported VMs.
What is a Virtual Machine?
A Virtual Machine (VM) is a software computer that, like a physical computer, runs an operating system and
applications. The VM is comprised of a set of specification and configuration files and is backed by the physical
resources of a host. Every VM has virtual devices that provide the same functionality as physical hardware, and
can have additional benefits in terms of portability, manageability, and security. In addition, you can tailor the
boot behavior of each VM to your specific requirements - for more information refer to Section 9.1, “VM Boot
Behavior”.
XenServer supports guests with any combination of IPV4 or IPv6 configured addresses.
2.1. Creating VMs
2.1.1. Using VM Templates
VMs are prepared from templates. A template is a "gold image" that contains all the various configuration settings
to instantiate a specific VM. XenServer ships with a base set of templates, which are "raw" VMs, on which you
can install an operating system. Different operating systems require different settings in order to run at their
best. Linux templates create ParaVirtualized (PV) guests, whereas Windows templates create Hardware Virtual
Machine (HVM) guests. XenServer templates are tuned to maximize operating system performance.
There are two basic methods by which you can create VMs from templates:
Using a complete pre-configured template, for example the Demo Linux VM.
Installing an operating system from a CD or an ISO image onto the appropriate provided template.
You install operating systems onto VMs from either a vendor installation CD, or from an ISO repository, or can
choose use a complete pre-configured OS instance.
Chapter 4, Creating Windows VMs describes how to install Windows operating systems onto VMs.
Chapter 5, Creating Linux VMs describes how to install Linux operating systems onto VMs.
2.2. Other Methods of VM Creation
In addition to creating VMs from the provided templates, there are 3 other methods that you can use to create
VMs.
1. Physical to Virtual Conversion (P2V)
2. Cloning an existing VM
3. Importing an exported VM
2.2.1. Physical to Virtual Conversion (P2V)
Physical to Virtual Conversion (P2V) is the process by which an existing Windows operating system on a physical
server — its file system, configuration, and so on — is converted to a virtualized instance of the operating system.
This is then is transferred, instantiated, and started as a VM on the XenServer host.
2.2.2. Cloning an Existing VM
You can make a copy of an existing VM by cloning from a template. Templates are ordinary VMs which are intended
to be used as master copies to instantiate VMs from. A VM can be customized and converted into a template;