ISO IEC 17203:2011 pdf – lnformation technology -Open Virtualization Format (ovF) specification
ISO IEC 17203:2011 pdf – lnformation technology -Open Virtualization Format (ovF) specification.
The value of the ovfenv:id attribute of the Environment element shall match the value of the ovf:idattribute of the virtualSystem entity describing this virtual machine.
The PlatformSection element contains optional information provided by the deployment platform.
Elements Kind, version, and vendor describe deployment platform vendor details; these elements areexperimental.Elements Locale and TimeZone describe the current locale and time zone; these
elements are experimental.
The PropertySection element contains Property elements with keylvalue pairs corresponding to allproperties specified in the OVF descriptor for the current virtual machine, as well as properties specifiedfor the immediate parent virtualSystemCollection, if one exists. The environment presents
properties as a simple list to make it easy for applications to parse.Furthermore, the single list formatsupports the override semantics where a property on a virtualsystem may override one defined on aparent virtualSystemCollection.The overridden property shall not be in the list. Overriding mayoccur if a property in the current virtual machine and a property in the parent
virtualsystemcollection has identical ovf :key, ovf:class, and ovf:instance attributevalues; see 9.5. In this case, the value of an overridden parent property may be obtained by adding adifferently named child property referencing the parent property with a macro; see 9.5.
An Entity element shall exist for each sibling virtualsystem and virtualsystemCollection, ifany are present. The value of the ovfenv:id attribute of the Entity element shall match the value ofthe ovf:id attribute of the sibling entity.The Entity elements contain the property keylvalue pairs inthe sibling’s OVF environment documents, so the content of an Entity element for a particular siblingshall contain the exact Propertysection seen by that sibling.This information can be used, forexample, to make configuration information such as lP addresses available to virtualsystems beingpart of a multi-tiered application.
Table 8 shows the core sections that are defined.
The environment document is extensible by providing new section types. A consumer of the documentshould ignore unknown section types and elements.
The environment document information can be communicated in a number of ways to the guest software.These ways are called transport types.The transport types are specified in the OVF descriptor by theovf:transport attribute of virtualHardwaresection.Several transport types may be specified,separated by a single space character, in which case an implementation is free to use any of them. Thetransport types define methods by which the environment document is communicated from the
deployment platform to the guest software.
To enable interoperability, this specification defines an “iso”transport type which all implementationsthat support CD-ROM devices are required to support. The iso transport communicates the environmentdocument by making a dynamically generated ISO image available to the guest software.To support theiso transport type, prior to booting a virtual machine, an implementation shall make an IS0 read-onlydisk image available as backing for a disconnected CD-ROM. lf the iso transport is selected for a
VirtualHardwareSection, at least one disconnected CD-ROM device shall be present in this section.The generated lSO image shall comply with the ISO 9660 specification with support for Joliet extensions.The lSO image shall contain the OVF environment for this particular virtual machine, and the environmentshall be present in an XML file named ovf-env . xml that is contained in the root directory of the lSoimage.The guest software can now access the information using standard guest operating system tools.lf the virtual machine prior to booting had more than one disconnected CD-ROM, the guest software mayhave to scan connected CD-ROM devices in order to locate the lSO image containing the ovf-env. xm.lfile.
The lSO image containing the OVF environment shall be made available to the guest software on everyboot of the virtual machine.
Support for the “iso” transport type is not a requirement for virtual hardware architectures or guestoperating systems which do not have CD-ROM device support.
To be compliant with this specification, any transport format other than iso shall be given by a URl whichidentifies an unencumbered specification on how to use the transport. The specification need not be
machine readable, but it shall be static and unique so that it may be used as a key by software reading anoVF descriptor to uniquely determine the format. The specification shall be sufficient for a skilled personto properly interpret the transport mechanism for implementing the protocols. lt is recommended thatthese uRis are resolvable.