73 lines
3.6 KiB
XML
73 lines
3.6 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<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"
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version="5.0"
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xml:id="module002-ch004-floating-ips">
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<title>Floating IP Addresses And Security Rules</title>
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<para>OpenStack Networking has the concept of Fixed IPs and
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Floating IPs. Fixed IPs are assigned to an instance on
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creation and stay the same until the instance is explicitly
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terminated. Floating ips are ip addresses that can be
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dynamically associated with an instance. This address can be
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disassociated and associated with another instance at any
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time.</para>
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<para>Various tasks carried out by Floating IP's as of
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now.</para>
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<itemizedlist>
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<listitem>
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<para>create IP ranges under a certain group, only
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available for admin role.</para>
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</listitem>
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<listitem>
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<para>allocate an floating IP to a certain tenant,
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only available for admin role.</para>
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</listitem>
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<listitem>
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<para>deallocate an floating IP from a certain
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tenant</para>
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</listitem>
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<listitem>
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<para>associate an floating IP to a given
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instance</para>
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</listitem>
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<listitem>
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<para>disassociate an floating IP from a certain
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instance</para>
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</listitem>
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</itemizedlist>
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<para>Just as shown by the above figure, we will have
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nova-network-api to support nova client floating
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commands. nova-network-api will invoke neutron cli lib
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to interactive with neutron server via API. The data
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about floating IPs will be stored in to neutron DB.
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Neutron Agent, which is running on compute host will
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enforce the floating IP.</para>
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<para><guilabel>Multiple Floating
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IP Pools</guilabel></para>
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<para>The L3 API in OpenStack Networking supports multiple
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floating IP pools. In OpenStack Networking, a floating
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IP pool is represented as an external network and a
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floating IP is allocated from a subnet associated with
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the external network. Since each L3 agent can be
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associated with at most one external network, we need
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to invoke multiple L3 agent to define multiple
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floating IP pools. 'gateway_external_network_id'in L3
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agent configuration file indicates the external
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network that the L3 agent handles. You can run
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multiple L3 agent instances on one host.</para>
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<para>In addition, when you run multiple L3 agents, make
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sure that handle_internal_only_routers is set to
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Trueonly for one L3 agent in an OpenStack Networking
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deployment and set to Falsefor all other L3 agents.
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Since the default value of this parameter is True, you
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need to configure it carefully.</para>
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<para>Before starting L3 agents, you need to create
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routers and external networks, then update the
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configuration files with UUID of external networks and
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start L3 agents.</para>
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<para>For the first agent, invoke it with the following
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l3_agent.ini where handle_internal_only_routers is
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True.</para>
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</chapter>
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