| 1 | <?xml version='1.0' encoding='UTF-8'?>
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| 2 | <!DOCTYPE topic PUBLIC "-//OASIS//DTD DITA Topic//EN" "topic.dtd">
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| 3 | <topic xml:lang="en-us" id="ovf-about">
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| 4 | <title>About the OVF Format</title>
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| 5 |
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| 6 | <body>
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| 7 | <p>OVF is a cross-platform standard supported by many virtualization products which enables the creation of
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| 8 | ready-made virtual machines that can then be imported into a hypervisor such as <ph
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| 9 | conkeyref="vbox-conkeyref-phrases/product-name"/>. <ph conkeyref="vbox-conkeyref-phrases/product-name"/> makes
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| 10 | OVF import and export easy to do, using <ph conkeyref="vbox-conkeyref-phrases/vbox-mgr"/> or the command-line
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| 11 | interface. </p>
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| 12 | <p>Using OVF enables packaging of <i>virtual appliances</i>. These are disk images, together with configuration
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| 13 | settings that can be distributed easily. This way one can offer complete ready-to-use software packages, including
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| 14 | OSes with applications, that need no configuration or installation except for importing into <ph
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| 15 | conkeyref="vbox-conkeyref-phrases/product-name"/>. </p>
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| 16 | <note>
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| 17 | <p>The OVF standard is complex, and support in <ph conkeyref="vbox-conkeyref-phrases/product-name"/> is an ongoing
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| 18 | process. In particular, no guarantee is made that <ph conkeyref="vbox-conkeyref-phrases/product-name"/> supports
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| 19 | all appliances created by other virtualization software. For a list of known limitations, see <xref
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| 20 | href="KnownIssues.dita">Known Limitations</xref>. </p>
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| 21 | </note>
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| 22 | <p>Appliances in OVF format can appear in the following variants: </p>
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| 23 | <ul>
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| 24 | <li>
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| 25 | <p>They can come in several files, as one or several disk images, typically in the widely-used VMDK format. See
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| 26 | <xref href="vdidetails.dita"/>. They also include a textual description file in an XML dialect with an
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| 27 | <filepath>.ovf</filepath> extension. These files must then reside in the same directory for <ph
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| 28 | conkeyref="vbox-conkeyref-phrases/product-name"/> to be able to import them. </p>
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| 29 | </li>
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| 30 | <li>
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| 31 | <p>Alternatively, the above files can be packed together into a single archive file, typically with an
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| 32 | <filepath>.ova</filepath> extension. Such archive files use a variant of the TAR archive format and can
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| 33 | therefore be unpacked outside of <ph conkeyref="vbox-conkeyref-phrases/product-name"/> with any utility that
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| 34 | can unpack standard TAR files. </p>
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| 35 | </li>
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| 36 | </ul>
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| 37 | <note>
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| 38 | <p>OVF cannot describe snapshots that were taken for a virtual machine. As a result, when you export a virtual
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| 39 | machine that has snapshots, only the current state of the machine will be exported. The disk images in the
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| 40 | export will have a <i>flattened</i> state identical to the current state of the virtual machine. </p>
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| 41 | </note>
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| 42 | </body>
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| 43 |
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| 44 | </topic>
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