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<h1>Storage volume encryption XML format</h1>
<ul id="toc"></ul>
<h2><a name="StorageEncryption">Storage volume encryption XML</a></h2>
<p>
Storage volumes may be encrypted, the XML snippet described below is used
to represent the details of the encryption. It can be used as a part
of a domain or storage configuration.
</p>
<p>
The top-level tag of volume encryption specification
is <code>encryption</code>, with a mandatory
attribute <code>format</code>. Currently defined values
of <code>format</code> are <code>default</code> and <code>qcow</code>.
Each value of <code>format</code> implies some expectations about the
content of the <code>encryption</code> tag. Other format values may be
defined in the future.
</p>
<p>
The <code>encryption</code> tag can currently contain a sequence of
<code>secret</code> tags, each with mandatory attributes <code>type</code>
and <code>uuid</code>. The only currently defined value of
<code>type</code> is <code>passphrase</code>. <code>uuid</code>
refers to a secret known to libvirt. libvirt can use a secret value
previously set using <code>virSecretSetValue()</code>, or, if supported
by the particular volume format and driver, automatically generate a
secret value at the time of volume creation, and store it using the
specified <code>uuid</code>.
</p>
<h3><a name="StorageEncryptionDefault">"default" format</a></h3>
<p>
<code><encryption format="default"/></code> can be specified only
when creating a volume. If the volume is successfully created, the
encryption formats, parameters and secrets will be auto-generated by
libvirt and the attached <code>encryption</code> tag will be updated.
The unmodified contents of the <code>encryption</code> tag can be used
in later operations with the volume, or when setting up a domain that
uses the volume.
</p>
<h3><a name="StorageEncryptionQcow">"qcow" format</a></h3>
<p>
The <code>qcow</code> format specifies that the built-in encryption
support in <code>qcow</code>- or <code>qcow2</code>-formatted volume
images should be used. A single
<code><secret type='passphrase'></code> element is expected. If
the <code>secret</code> element is not present during volume creation,
a secret is automatically generated and attached to the volume.
</p>
<h2><a name="example">Example</a></h2>
<p>
Here is a simple example, specifying use of the <code>qcow</code> format:
</p>
<pre>
<encryption format='qcow'>
<secret type='passphrase' uuid='c1f11a6d-8c5d-4a3e-ac7a-4e171c5e0d4a' />
</encryption></pre>
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