<htmlxmlns="http://www.w3.org/1999/xhtml"><head><metahttp-equiv="Content-Type"content="text/html; charset=ISO-8859-1"/><linkrel="stylesheet"type="text/css"href="libvirt.css"/><linkrel="SHORTCUT ICON"href="/32favicon.png"/><title>Introduction</title></head><body><divid="container"><divid="intro"><divid="adjustments"></div><divid="pageHeader"></div><divid="content2"><h1class="style1">Introduction</h1><p>Libvirt is a C toolkit to interact with the virtualization capabilities
ofrecent versions of Linux (and other OSes), but libvirt won't try to
provideall possible interfaces for interacting with the virtualization
features.</p><p>To avoid ambiguity about the terms used here here are the definitions
forsome of the specific concepts used in libvirt documentation:</p><ul><li>a <strong>node</strong>is a single physical machine</li>
<li>an <strong>hypervisor</strong>is a layer of software allowing
tovirtualize a node in a set of virtual machines with possibly
differentconfigurations than the node itself</li>
<li>a <strong>domain</strong>is an instance of an operating system
runningon a virtualized machine provided by the hypervisor</li>
</ul><pstyle="text-align: center"><imgalt="Hypervisor and domains running on a node"src="node.gif"/></p><p>Now we can define the goal of libvirt: to provide the lowest
possiblegeneric and stable layer to manage domains on a node.</p><p>This implies the following:</p><ul><li>the API is not targetted to a single virtualization environment,
itcurrently supports Xen and QEmu/KVM. This also implies that some
veryspecific capabilities which are not generic enough may not be
provided aslibvirt APIs</li>
<li>the API should allow to do efficiently and cleanly all the
operationsneeded to manage domains on a node</li>
<li>the API will not try to provide hight level multi-nodes
managementfeatures like load balancing, though they could be implemented
on top oflibvirt</li>
<li>stability of the API is a big concern, libvirt should
isolateapplications from the frequent changes expected at the lower level
of thevirtualization framework</li>
</ul><p>So libvirt should be a building block for higher level management toolsand
for applications focusing on virtualization of a single node (the
onlyexception being domain migration between node capabilities which may need
tobe added at the libvirt level). Where possible libvirt should be
extendableto be able to provide the same API for remote nodes, however this
is not thecase at the moment, the code currently handle only local node
accesses(extension for remote access support is being worked on, see<ahref="bugs.html">the mailing list</a>discussions about it).</p></div></div><divclass="linkList2"><divclass="llinks2"><h3class="links2"><span>main menu</span></h3><ul><li><ahref="index.html">Home</a></li><li><ahref="news.html">Releases</a></li><li><ahref="intro.html">Introduction</a></li><li><ahref="architecture.html">libvirt architecture</a></li><li><ahref="downloads.html">Downloads</a></li><li><ahref="format.html">XML Formats</a></li><li><ahref="python.html">Binding for Python</a></li><li><ahref="errors.html">Handling of errors</a></li><li><ahref="FAQ.html">FAQ</a></li><li><ahref="bugs.html">Reporting bugs and getting help</a></li><li><ahref="html/index.html">API Menu</a></li><li><ahref="examples/index.html">C code examples</a></li><li><ahref="ChangeLog.html">Recent Changes</a></li></ul></div><divclass="llinks2"><h3class="links2"><span>related links</span></h3><ul><li><ahref="https://www.redhat.com/archives/libvir-list/">Mail archive</a></li><li><ahref="https://bugzilla.redhat.com/bugzilla/buglist.cgi?product=Fedora+Core&component=libvirt&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&bug_status=MODIFIED&short_desc_type=allwordssubstr&short_desc=&long_desc_type=allwordssubstr">Open bugs</a></li><li><ahref="http://virt-manager.et.redhat.com/">virt-manager</a></li><li><ahref="http://search.cpan.org/~danberr/Sys-Virt-0.1.0/">Perl bindings</a></li><li><ahref="http://www.cl.cam.ac.uk/Research/SRG/netos/xen/index.html">Xen project</a></li><li><formaction="search.php"enctype="application/x-www-form-urlencoded"method="get"><inputname="query"type="text"size="12"value="Search..."/><inputname="submit"type="submit"value="Go"/></form></li><li><ahref="http://xmlsoft.org/"><imgsrc="Libxml2-Logo-90x34.gif"alt="Made with Libxml2 Logo"/></a></li></ul><pclass="credits">Graphics and design by <ahref="mail:dfong@redhat.com">Diana Fong</a></p></div></div><divid="bottom"><pclass="p1"></p></div></div></body></html>
