80 lines
3.8 KiB
XML
80 lines
3.8 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE section [
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<!ENTITY % openstack SYSTEM "../../common/entities/openstack.ent">
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%openstack;
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]>
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<section 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"
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version="5.0"
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xml:id="arch-guide-openstack-on-openstack">
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<?dbhtml stop-chunking?>
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<title>OpenStack on OpenStack</title>
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<para>In some cases it is necessary to run OpenStack nested on top
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of another OpenStack cloud. This scenario enables you to manage
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and provision complete OpenStack cloud environments on
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instances running on hypervisors and servers that the underlying
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OpenStack cloud controls. Public cloud providers can use
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this technique to manage the upgrade and
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maintenance process on complete OpenStack-based clouds.
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Developers and those testing OpenStack can also use this
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guidance to provision their own OpenStack environments on
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available OpenStack Compute resources, whether public or
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private.</para>
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<section xml:id="challenges-for-nested-cloud">
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<title>Challenges</title>
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<para>The network aspect of deploying a nested cloud is the most
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complicated aspect of this architecture. You must expose VLANs
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to the physical ports on which the underlying cloud runs,
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as the bare metal cloud owns all the
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hardware, but you must also expose them to the nested
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levels as well. Alternatively, you can use the network overlay
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technologies on the OpenStack cloud running on OpenStack to provide
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the required software defined networking for the deployment.</para>
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</section>
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<section xml:id="hypervisor-nested-cloud">
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<title>Hypervisor</title>
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<para>A key question to address in this scenario is which
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approach you should take to provide a nested
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hypervisor in OpenStack. This decision influences which
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operating systems you use for the deployment of the nested
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OpenStack deployments.</para>
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</section>
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<section xml:id="possible-solutions-nested-cloud-deployment">
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<title>Possible solutions: deployment</title>
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<para>Deployment of a full stack can be challenging but you can mitigate
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this difficulty by creating a Heat template to deploy the
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entire stack or a configuration management system. After creating
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the Heat template, you can automate the deployment of additional stacks.</para>
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<para>The OpenStack-on-OpenStack project (<glossterm>TripleO</glossterm>)
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addresses this issue. Currently, however, the project does
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not completely cover nested stacks. For more information, see
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<link xlink:href="https://wiki.openstack.org/wiki/TripleO">
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https://wiki.openstack.org/wiki/TripleO</link>.</para>
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</section>
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<section xml:id="possible-solutions-nested-cloud-hypervisor">
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<title>Possible solutions: hypervisor</title>
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<para>In the case of running TripleO, the underlying OpenStack
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cloud deploys the Compute nodes as bare-metal. You then deploy
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OpenStack on these Compute bare-metal servers with the
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appropriate hypervisor, such as KVM.</para>
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<para>In the case of running smaller OpenStack clouds for testing
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purposes, where performance is not a critical factor, you can use
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QEMU instead. It is also possible to run a KVM hypervisor in an instance
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(see <link xlink:href="http://davejingtian.org/2014/03/30/nested-kvm-just-for-fun/">
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http://davejingtian.org/2014/03/30/nested-kvm-just-for-fun/</link>),
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though this is not a supported configuration, and could be a
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complex solution for such a use case.</para>
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</section>
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<section xml:id="nested-cloud-diagram">
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<title>Diagram</title>
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<para>
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<mediaobject>
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<imageobject>
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<imagedata contentwidth="4in" fileref="../figures/Specialized_OOO.png"/>
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</imageobject>
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</mediaobject>
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</para>
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</section>
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</section>
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