74 lines
3.9 KiB
XML
74 lines
3.9 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<section xml:id="example-compute-installation-architecture"
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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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<title>Example Compute Installation Architectures</title>
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<para>OpenStack architecture consists of these major
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components: Compute, Object Storage, Identity, and Images.
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A common Identity component provides authentication for
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users to have access to these components. The Image
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service stores and serves images to run virtual machines.
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Compute uses a shared-nothing, messaging-based
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architecture. While very flexible, the fact that you can
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install each nova- service on an independent server means
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there are many possible methods for installing OpenStack
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Compute. The only co-dependency between possible
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multi-node installations is that the Dashboard must be
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installed on a server running the nova-api service. Here
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are the types of installation architectures for OpenStack
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Compute with the Image and Identity Services:</para>
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<itemizedlist>
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<listitem>
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<para xmlns="http://docbook.org/ns/docbook"
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>Single node, Compute-only: Only one server runs
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all nova- services and also drives all the virtual
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instances. Use this configuration only for trying
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out OpenStack Compute, or for development
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purposes.</para></listitem>
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<listitem><para>Two nodes, Compute-only: A cloud controller node runs the nova-
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services except for nova-compute, and a compute
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node runs nova-compute. A client computer is
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likely needed to bundle images and interfacing to
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the servers, but a client is not required. Use
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this configuration for proof of concepts or
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development environments. </para></listitem>
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<listitem>
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<para xmlns="http://docbook.org/ns/docbook">Multiple
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nodes, Compute-only: You can add more compute
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nodes to the two node installation by simply
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installing nova-compute on an additional server
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and copying a nova.conf file to the added node.
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This would result in a multiple node installation.
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You can also add a volume controller and a network
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controller as additional nodes in a more complex
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multiple node installation. A minimum of 4 nodes
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is best for running multiple virtual instances
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that require a lot of processing power.</para>
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</listitem>
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</itemizedlist>
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<para>This is an illustration of one possible multiple server installation of OpenStack
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Compute; virtual server networking in the cluster may vary.</para>
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<para><inlinemediaobject>
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<imageobject>
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<imagedata scale="80" fileref="figures/NOVA_install_arch.png"/></imageobject>
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</inlinemediaobject></para>
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<para>An alternative architecture would be to add more messaging servers if you notice a lot
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of back up in the messaging queue causing performance problems. In that case you would
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add an additional RabbitMQ server in addition to or instead of scaling up the database
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server. Your installation can run any nova- service on any server as long as the
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nova.conf is configured to point to the RabbitMQ server and the server can send messages
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to the server.</para>
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<para>Multiple installation architectures are possible, here is another example
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illustration. </para>
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<para><inlinemediaobject>
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<imageobject>
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<imagedata scale="40" fileref="figures/NOVA_compute_nodes.png"/></imageobject>
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</inlinemediaobject></para>
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</section>
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