XML Format

The library use an XML format to describe domains, as input to virDomainCreateLinux() +XML Format

XML Format

This section describes the XML format used to represent domains, there are +variations on the format based on the kind of domains run and the options +used to launch them:

Normal paravirtualized Xen domains

Fully virtualized Xen domains

The formats try as much as possible to follow the same structure and reuse +elements and attributes where it makes sense.

Normal paravirtualized Xen +guests:

The library use an XML format to describe domains, as input to virDomainCreateLinux() and as the output of virDomainGetXMLDesc(), the following is an example of the format as returned by the shell command virsh xmldump fc4 , where fc4 was one of the running domains:

<domain type='xen' id='18'>
@@ -81,4 +85,48 @@ poweroff. There is various actions possible when this happen:
destroy
   ...
 </domain>

While the format may be extended in various ways as support for more hypervisor types and features are added, it is expected that this core subset -will remain functional in spite of the evolution of the library.

main menu

Fully virtualized guests +(added in 0.1.3):

Here is an example of a domain description used to start an fully +virtualized (a.k.a. HVM) Xen domain. This requires hardware virtualization +support at the processor level but allows to run unmodified operating +systems:

<domain type='xen' id='3'>
+  <name>fv0</name>
+  <uuid>4dea22b31d52d8f32516782e98ab3fa0</uuid>
+  <os>
+    <type>hvm</type>
+    <loader>/usr/lib/xen/boot/hvmloader</loader>
+    <boot dev='hda'/>
+  </os>
+  <memory>524288</memory>
+  <vcpu>1</vcpu>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>restart</on_crash>
+  <devices>
+    <emulator>/usr/lib/xen/bin/qemu-dm</emulator>
+    <interface type='bridge'>
+      <source bridge='xenbr0'/>
+      <mac address='00:16:3e:5d:c7:9e'/>
+      <script path='vif-bridge'/>
+    </interface>
+    <disk type='file'>
+      <source file='/root/fv0'/>
+      <target dev='ioemu:hda'/>
+    </disk>
+    <graphics type='vnc'/>
+  </devices>
+</domain>

There is a few things to notice specifically for HVM domains:

the <os> block description is very different, first it indicates + that the type is 'hvm' for hardware virtualization, then instead of a + kernel, boot and command line arguments, it points to an os boot loader + which ill extract the boot informations from the boot device specified in + a separate boot element
the <devices> section includes an emulator entry pointing to an + additional program in charge of emulating the devices
the disk entry indicates in the dev target section that the emulation + for the drive is the first IDE disk device hda
the <devices> section also include at least one entry for the + graphic device used to render the os. Currently there is just 2 types + possible 'vnc' or 'sdl'

It is likely that the HVM description gets additional elements and +attributes as the support for fully virtualized domain expands especially for +the kind of devices emulated and the graphic options offered.

XML Format

XML Format

Normal paravirtualized Xen +guests:

main menu

related links

Fully virtualized guests +(added in 0.1.3):

main menu

related links

0.1.2: Jul 3 2006

0.1.1: Jun 21 2006

0.1.0: Apr 10 2006

XML Format

Normal paravirtualized Xen +guests:

Fully virtualized guests +(added in 0.1.3):

Binding for Python

Releases

0.1.2: Jul 3 2006

0.1.1: Jun 21 2006

0.1.0: Apr 10 2006

0.1.2: Jul 3 2006

0.1.1: Jun 21 2006

0.1.0: Apr 10 2006