Hypervisor: Provides the ability to virtualize a node within a set of
virtual machines.
Domain: An instance of an OS that runs on a virtual machine. The machine
itself is provided by the hypervisor defined above.
Libvirt provides the capability to manage the domains running on a node in a
hypervisor instance. To do this in a manner that is independent of the hypervisor
technology used, libvirt will need to provide the lowest common denominator
of the virtualization support. In this way the API can provide a generic way to
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Xen Future
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manage the domains on the nodes in a hypervisor for any supported virtualization
framework. By focusing on the smallest common subset of the operations needed for
the management of a virtual domain, libvirt provides the ability and the opportunity
to layer new functionality on top of the existing API. This functionality allows it to
build applications that can provide a higher level of management tools. This will also
enable libvirt to focus on stability in the functions that it provides.
In a Xen environment, user space applications that use libvirt will need to operate in
the dom0 environment. These applications can be run in two ways to connect to Xen:
1. Root access:
A read/write connection to the Xen store.
Use the HTTP RPC layer to connect to xend.
Use the hypervisor call mechanism.
2. Normal access:
This is mainly used for providing read only functions. The
user application will need to connect to a proxy that is
running as root and request information.
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