156 lines
7.7 KiB
XML
156 lines
7.7 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
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xml:id="ch_overview">
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<?dbhtml stop-chunking?>
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<title>Architecture</title>
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<warning>
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<para>We are updating this material for Icehouse. You may find structure
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and/or content issues during this process.</para>
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</warning>
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<section xml:id="architecture_overview">
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<title>Overview</title>
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<para>The <glossterm>OpenStack</glossterm> project is an open source cloud
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computing platform that supports all types of cloud environments. The
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project aims for simple implementation, massive scalability, and a rich
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set of features. Cloud computing experts from around the world
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contribute to the project.</para>
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<para>OpenStack provides an Infrastructure-as-a-Service
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(<glossterm>IaaS</glossterm>) solution through a variety of complemental
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services. Each service offers an application programming interface
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(<glossterm>API</glossterm>) that facilitates this integration. The
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following table provides a list of OpenStack services:</para>
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<xi:include href="../common/ch_getstart.xml"
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xpointer="element(table1)"/>
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<para>This guide describes how to deploy these services in a functional
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test environment and, by example, teaches you how to build a production
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environment.</para>
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</section>
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<section xml:id="architecture_conceptual-architecture">
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<title>Conceptual architecture</title>
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<para>Launching a virtual machine or instance involves many interactions
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among several services. The following diagram provides the conceptual
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architecture of a typical OpenStack environment.</para>
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<figure xml:id="conceptual-architecture">
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<title>Conceptual architecture</title>
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<mediaobject>
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<imageobject>
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<imagedata contentwidth="6in"
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fileref="../common/figures/openstack_havana_conceptual_arch.png"/>
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</imageobject>
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</mediaobject>
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</figure>
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</section>
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<section xml:id="architecture_example-architectures">
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<title>Example architectures</title>
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<para>OpenStack is highly configurable to meet different needs with various
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compute, networking, and storage options. This guide enables you to
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choose your own OpenStack adventure using a combination of basic and
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optional services. This guide uses the following example
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architectures:</para>
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<itemizedlist>
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<listitem>
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<para>Two-node architecture with legacy networking. See <xref linkend="example-architecture-with-legacy-networking"/>.</para>
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<itemizedlist>
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<listitem>
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<para>The basic
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<glossterm baseform="cloud controller node">controller node</glossterm>
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runs the Identity service, Image Service, management portion of
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Compute, and the dashboard necessary to launch a simple instance.
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It also includes supporting services such as MySQL,
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<glossterm>AMQP</glossterm>, and
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<glossterm>NTP</glossterm>.</para>
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<para>Optionally, the controller node also runs portions of
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Block Storage, Object Storage, Database Service, Orchestration,
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and Telemetry. These components provide additional features for
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your environment.</para>
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</listitem>
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<listitem>
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<para>The basic <glossterm>compute node</glossterm> runs the
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<glossterm>hypervisor</glossterm> portion of Compute,
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which operates <glossterm>tenant</glossterm>
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<glossterm baseform="virtual machine (VM)">virtual machines</glossterm>
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or instances. By default, Compute uses
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<glossterm baseform="kernel-based VM (KVM)">KVM</glossterm>
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as the <glossterm>hypervisor</glossterm>. Compute also
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provisions and operates tenant networks and implements
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<glossterm baseform="security group">security groups</glossterm>.
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You can run more than one compute node.</para>
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<para>Optionally, the compute node also runs the Telemetry
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agent. This component provides additional features for
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your environment.</para>
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</listitem>
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</itemizedlist>
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<note>
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<para>When you implement this architecture, skip
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<xref linkend="section_neutron-networking" /> in
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<xref linkend="ch_networking" />. To use optional services, you
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might need to install additional nodes, as described in
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subsequent chapters.</para>
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</note>
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<figure xml:id="example-architecture-with-legacy-networking">
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<title>Two-node architecture with legacy networking</title>
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<mediaobject>
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<imageobject>
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<imagedata contentwidth="6in"
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fileref="figures/installguide_arch-nova.png"/>
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</imageobject>
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</mediaobject>
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</figure>
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</listitem>
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<listitem>
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<para>Three-node architecture with OpenStack Networking (neutron). See <xref linkend="example-architecture-with-neutron-networking"/>.</para>
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<itemizedlist>
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<listitem>
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<para>The basic controller node runs the Identity service, Image
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Service, management portions of Compute and Networking,
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Networking plug-in, and the dashboard. It also includes
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supporting services such as MySQL, AMQP, and NTP.</para>
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<para>Optionally, the controller node also runs portions of
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Block Storage, Object Storage, Database Service, Orchestration,
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and Telemetry. These components provide additional features for
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your environment.</para>
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</listitem>
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<listitem>
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<para>The network node runs the Networking plug-in, layer 2 agent,
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and several layer 3 agents that provision and operate tenant
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networks. Layer 2 services include provisioning of virtual
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networks and tunnels. Layer 3 services include routing,
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<glossterm baseform="Network Address Translation (NAT)">NAT</glossterm>
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, and <glossterm>DHCP</glossterm>. This node also handles
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external (internet) connectivity for tenant virtual machines
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or instances.</para>
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</listitem>
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<listitem>
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<para>The compute node runs the hypervisor portion of Compute,
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which operates tenant virtual machines or instances. By default
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Compute uses KVM as the hypervisor. The compute node also runs
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the Networking plug-in and layer 2 agent which operate tenant
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networks and implement security groups. You can run more than
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one compute node.</para>
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<para>Optionally, the compute node also runs the Telemetry
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agent. This component provides additional features for
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your environment.</para>
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</listitem>
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</itemizedlist>
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<note>
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<para>When you implement this architecture, skip
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<xref linkend="section_nova-networking" /> in
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<xref linkend="ch_networking" />. To use optional services, you
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might need to install additional nodes, as described in
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subsequent chapters.</para>
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</note>
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<figure xml:id="example-architecture-with-neutron-networking">
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<title>Three-node architecture with OpenStack Networking (neutron)</title>
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<mediaobject>
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<imageobject>
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<imagedata contentwidth="6in"
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fileref="figures/installguide_arch-neutron.png"/>
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</imageobject>
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</mediaobject>
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</figure>
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</listitem>
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</itemizedlist>
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</section>
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</chapter>
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