Add Docker to Hypervisors section

Docker is an open-source engine which automates the deployment of
applications as highly portable, self-sufficient containers which
are independent of hardware, language, framework, packaging system
and hosting provider.

Support for Docker has been added in Havana.

This patch adds the a section on Docker to the Hypervisors
section of the Configuration Reference. It requires the config table
found in this patch: https://review.openstack.org/#/c/45922/
before merging.

Change-Id: If89225036cccad9cc2c8eb3ce7cc3bf6bd710cf0
Closes-Bug: 1221207

doc/common/section_docker.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<section xmlns="http://docbook.org/ns/docbook"
+xmlns:xi="http://www.w3.org/2001/XInclude"
+xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
+xml:id="docker">
+    <title>Docker Driver</title>
+    <para> The Docker driver is a hypervisor driver for OpenStack Compute,
+    introduced with the Havana release. Docker is an open-source engine which
+    automates the deployment of applications as highly portable, self-sufficient
+    containers which are independent of hardware, language, framework, packaging
+    system and hosting provider. Docker extends LXC with a high level API
+    providing a lightweight virtualization solution that runs processes in
+    isolation. It provides a way to automate software deployment in a secure and
+    repeatable environment. A standard container in Docker contains a software
+    component along with all of its dependencies - binaries, libraries,
+    configuration files, scripts, virtualenvs, jars, gems and tarballs. Docker
+    can be run on any x86_64 Linux kernel that supports cgroups and aufs. Docker
+    is a way of managing LXC containers on a single machine. However used behind
+    OpenStack Compute makes Docker much more powerful since it’s then possible
+    to manage several hosts which will then manage hundreds of containers. The
+    current Docker project aims for full OpenStack compatibility. Containers
+    don't aim to be a replacement for VMs, they are just complementary in the
+    sense that they are better for specific use cases. Compute's support for VMs
+    is currently advanced thanks to the variety of hypervisors running VMs.
+    However it's not the case for containers even though libvirt/LXC is a good
+    starting point. Docker aims to go the second level of integration. </para>
+    <note><para>
+            Some OpenStack Compute features are not implemented by
+            the docker driver.  See the <link
+                xlink:href="http://wiki.openstack.org/HypervisorSupportMatrix">
+                hypervisor support matrix</link> for details.
+    </para></note>
+    <para>To enable Docker, ensure the following options are set in
+      <filename>/etc/nova/nova.conf</filename> on all hosts running the
+      <systemitem class="service">nova-compute</systemitem> service.
+      <programlisting language="ini">compute_driver=docker.DockerDriver</programlisting></para>
+    <para>Glance also needs to be configured to support the Docker container format, in
+    <filename>/etc/glance-api.conf</filename>:
+     <programlisting language="ini">container_formats = ami,ari,aki,bare,ovf,docker</programlisting></para>
+<xi:include href="tables/nova-docker.xml"/>
+</section>

doc/config-reference/compute/section_compute-hypervisors.xml

@@ -86,6 +86,14 @@
                 hardware through pluggable sub-drivers (for example, PXE for image
                 deployment, and IPMI for power management).</para>
         </listitem>
+        <listitem>
+            <para><link
+                    xlink:href="http://www.docker.io/"
+                    >Docker</link>is an open-source engine which automates the deployment of
+                    >applications as highly portable, self-sufficient containers which are
+                    >independent of hardware, language, framework, packaging system and hosting
+                    >provider.</para>
+        </listitem>
     </itemizedlist>
     <section xml:id="hypervisor-configuration-basics">
         <title>Hypervisor Configuration Basics</title>
@@ -113,4 +121,5 @@
     <xi:include href="../../common/section_powervm.xml"/>
     <xi:include href="../../common/section_hyper-v.xml"/>
     <xi:include href="../../common/section_baremetal.xml"/>
+    <xi:include href="../../common/section_docker.xml"/>
 </section>