145 lines
6.5 KiB
XML
145 lines
6.5 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<section xmlns="http://docbook.org/ns/docbook"
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version="5.0"
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xml:id="keystone-concepts">
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<?dbhtml stop-chunking?>
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<title>OpenStack Identity concepts</title>
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<para>The OpenStack<glossterm>Identity Service</glossterm> performs the
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following functions:</para>
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<itemizedlist spacing="compact">
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<listitem>
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<para>Tracking users and their permissions.</para>
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</listitem>
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<listitem>
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<para>Providing a catalog of available services with their API
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endpoints.</para>
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</listitem>
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</itemizedlist>
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<para>When installing OpenStack Identity service, you must register
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each service in your OpenStack installation. Identity service
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can then track which OpenStack services are installed, and
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where they are located on the network.</para>
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<para>To understand OpenStack Identity, you must understand the
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following concepts:</para>
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<variablelist>
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<varlistentry>
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<term>User</term>
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<listitem>
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<para>Digital representation of a person, system, or
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service who uses OpenStack cloud services. The
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Identity service validates that incoming requests
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are made by the user who claims to be making the
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call. Users have a login and may be assigned
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tokens to access resources. Users can be directly
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assigned to a particular tenant and behave as if
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they are contained in that tenant.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Credentials</term>
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<listitem>
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<para>Data that confirms the user's identity. For
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example: user name and password, user name and API
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key, or an authentication token provided by the
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Identity Service.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Authentication</term>
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<listitem>
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<para>The process of confirming the identity of a user.
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OpenStack Identity confirms an incoming request
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by validating a set of credentials supplied by the
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user.</para>
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<para>These credentials are initially a user name and
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password, or a user name and API key. When user
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credentials are validated, OpenStack Identity issues an
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authentication token which the user provides in subsequent
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requests.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Token</term>
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<listitem>
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<para>An alpha-numeric string of text used to access
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OpenStack APIs and resources. A token may be
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revoked at any time and is valid for a
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finite duration.</para>
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<para>While OpenStack Identity supports token-based
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authentication in this release, the intention is
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to support additional protocols in the future.
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Its main purpose is to be an integration service,
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and not aspire to be a full-fledged identity store
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and management solution.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Tenant</term>
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<listitem>
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<para>A container used to group or isolate resources.
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Tenants also group or isolate identity objects.
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Depending on the service operator, a tenant may map
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to a customer, account, organization, or project.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Service</term>
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<listitem>
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<para>An OpenStack service, such as Compute (nova),
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Object Storage (swift), or Image Service (glance).
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It provides one or more endpoints in which
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users can access resources and perform operations.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Endpoint</term>
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<listitem>
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<para>A network-accessible address where you access a service,
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usually a URL address. If you are using an extension for
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templates, an endpoint template can be created, which
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represents the templates of all the consumable services
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that are available across the regions.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Role</term>
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<listitem>
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<para>A personality with a defined set of user rights and
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privileges to perform a specific set of operations.</para>
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<para>In the Identity service, a token that is issued
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to a user includes the list of roles. Services that are
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being called by that user determine how they interpret the
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set of roles a user has and to which operations or
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resources each role grants access.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Keystone Client</term>
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<listitem>
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<para>A command line interface for the OpenStack
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Identity API. For example, users can run the
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<command>keystone service-create</command> and
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<command>keystone endpoint-create</command> commands
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to register services in their OpenStack
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installations.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<para>The following diagram shows the OpenStack Identity process
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flow:</para>
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<mediaobject>
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<imageobject role="fo">
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<imagedata
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fileref="figures/SCH_5002_V00_NUAC-Keystone.png"
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format="PNG" contentwidth="6in"/>
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</imageobject>
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<imageobject role="html">
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<imagedata
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fileref="figures/SCH_5002_V00_NUAC-Keystone.png"
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format="PNG" contentwidth="6in"/>
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</imageobject>
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</mediaobject>
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</section>
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