Add a sheepdog backend for the storage driver

This patch brings support to manage sheepdog pools and volumes to libvirt.
It uses the "collie" command-line utility that comes with sheepdog for that.

A sheepdog pool in libvirt maps to a sheepdog cluster.
It needs a host and port to connect to, which in most cases
is just going to be the default of localhost on port 7000.

A sheepdog volume in libvirt maps to a sheepdog vdi.
To create one specify the pool, a name and the capacity.
Volumes can also be resized later.

In the volume XML the vdi name has to be put into the <target><path>.
To use the volume as a disk source for virtual machines specify
the vdi name as "name" attribute of the <source>.
The host and port information from the pool are specified inside the host tag.

  <disk type='network'>
    ...
    <source protocol="sheepdog" name="vdi_name">
      <host name="localhost" port="7000"/>
    </source>
  </disk>

To work right this patch parses the output of collie,
so it relies on the raw output option. There recently was a bug which caused
size information to be reported wrong. This is fixed upstream already and
will be in the next release.

Signed-off-by: Sebastian Wiedenroth <wiedi@frubar.net>

4 files changed, 82 insertions, 1 deletions

diff --git a/docs/drivers.html.in b/docs/drivers.html.in
index 8ad2c3321..90b61962e 100644
--- a/docs/drivers.html.in
+++ b/docs/drivers.html.in
@@ -43,6 +43,7 @@
       <li><strong><a href="storage.html#StorageBackendSCSI">SCSI backend</a></strong></li>
       <li><strong><a href="storage.html#StorageBackendMultipath">Multipath backend</a></strong></li>
       <li><strong><a href="storage.html#StorageBackendRBD">RBD (RADOS Block Device) backend</a></strong></li>
+      <li><strong><a href="storage.html#StorageBackendSheepdog">Sheepdog backend</a></strong></li>
     </ul>
   </body>
 </html>
diff --git a/docs/schemas/storagepool.rng b/docs/schemas/storagepool.rng
index 75b6b514b..039798a9b 100644
--- a/docs/schemas/storagepool.rng
+++ b/docs/schemas/storagepool.rng
@@ -20,6 +20,7 @@
         <ref name='poolscsi'/>
         <ref name='poolmpath'/>
         <ref name='poolrbd'/>
+        <ref name='poolsheepdog'/>
       </choice>
     </element>
   </define>
@@ -115,6 +116,15 @@
     <ref name='sourcerbd'/>
   </define>
 
+  <define name='poolsheepdog'>
+    <attribute name='type'>
+      <value>sheepdog</value>
+    </attribute>
+    <ref name='commonmetadata'/>
+    <ref name='sizing'/>
+    <ref name='sourcesheepdog'/>
+  </define>
+
   <define name='sourceinfovendor'>
     <optional>
       <element name='vendor'>
@@ -496,6 +506,13 @@
     </element>
   </define>
 
+  <define name='sourcesheepdog'>
+    <element name='source'>
+      <ref name='sourceinfohost'/>
+      <ref name='sourceinfoname'/>
+    </element>
+  </define>
+
   <define name='name'>
     <data type='string'>
       <param name="pattern">[a-zA-Z0-9_\+\-]+</param>
diff --git a/docs/schemas/storagevol.rng b/docs/schemas/storagevol.rng
index 7a74331cd..0b9933d56 100644
--- a/docs/schemas/storagevol.rng
+++ b/docs/schemas/storagevol.rng
@@ -67,7 +67,7 @@
     <element name='target'>
       <optional>
         <element name='path'>
-          <ref name='absFilePath'/>
+          <data type='anyURI'/>
         </element>
       </optional>
       <ref name='format'/>
@@ -144,6 +144,7 @@
 
   <define name='formatfile'>
     <choice>
+      <value>unknown</value>
       <value>raw</value>
       <value>dir</value>
       <value>bochs</value>
diff --git a/docs/storage.html.in b/docs/storage.html.in
index b3484e811..26a949a7d 100644
--- a/docs/storage.html.in
+++ b/docs/storage.html.in
@@ -110,6 +110,9 @@
       <li>
         <a href="#StorageBackendRBD">RBD (RADOS Block Device) backend</a>
       </li>
+      <li>
+        <a href="#StorageBackendSheepdog">Sheepdog backend</a>
+      </li>
     </ul>
 
     <h2><a name="StorageBackendDir">Directory pool</a></h2>
@@ -565,5 +568,64 @@
       The RBD pool does not use the volume format type element.
     </p>
 
+    <h2><a name="StorageBackendSheepdog">Sheepdog pools</a></h2>
+    <p>
+      This provides a pool based on a Sheepdog Cluster.
+      Sheepdog is a distributed storage system for QEMU/KVM.
+      It provides highly available block level storage volumes that
+      can be attached to QEMU/KVM virtual machines.
+
+      The cluster must already be formatted.
+
+      <span class="since">Since 0.9.13</span>
+    </p>
+
+    <h3>Example pool input</h3>
+    <pre>
+      &lt;pool type="sheepdog"&gt;
+        &lt;name&gt;mysheeppool&lt;/name&gt;
+        &lt;source&gt;
+          &lt;name&gt;mysheeppool&lt;/name&gt;
+          &lt;host name='localhost' port='7000'/&gt;
+        &lt;/source&gt;
+      &lt;/pool&gt;</pre>
+
+    <h3>Example volume output</h3>
+    <pre>
+       &lt;volume&gt;
+         &lt;name&gt;myvol&lt;/name&gt;
+         &lt;key&gt;sheep/myvol&lt;/key&gt;
+         &lt;source&gt;
+         &lt;/source&gt;
+         &lt;capacity unit='bytes'&gt;53687091200&lt;/capacity&gt;
+         &lt;allocation unit='bytes'&gt;53687091200&lt;/allocation&gt;
+         &lt;target&gt;
+           &lt;path&gt;sheepdog:myvol&lt;/path&gt;
+           &lt;format type='unknown'/&gt;
+           &lt;permissions&gt;
+             &lt;mode&gt;00&lt;/mode&gt;
+             &lt;owner&gt;0&lt;/owner&gt;
+             &lt;group&gt;0&lt;/group&gt;
+           &lt;/permissions&gt;
+         &lt;/target&gt;
+       &lt;/volume&gt;</pre>
+
+    <h3>Example disk attachment</h3>
+    <p>Sheepdog images can be attached to Qemu guests.
+    Information about attaching a Sheepdog image to a
+    guest can be found
+    at the <a href="formatdomain.html#elementsDisks">format domain</a>
+    page.</p>
+
+    <h3>Valid pool format types</h3>
+    <p>
+      The Sheepdog pool does not use the pool format type element.
+    </p>
+
+    <h3>Valid volume format types</h3>
+    <p>
+      The Sheepdog pool does not use the volume format type element.
+    </p>
+
   </body>
 </html>