6.2.1. Creating Virtual Machines from Existing Templates
You can create a virtual machine from an existing template (either created by you, or one that came with the system). A template is a base virtual machine that is set with a unique configuration and settings. A virtual machine that is based on a particular template acquires the configurations and settings of the template. Thus, templates are used to conveniently and efficiently create a set of identical virtual machines. By default, virtual machines created from templates use thin provisioning. In the context of templates, thin provisioning means that all virtual machines based on a given template share the same base image as the template and must remain on the same data domain as the template.