cleaned up module001-ch007-keystone-arch keystone-arch

added space between user and represents
added space between tenant and can

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Shilla Saebi 2014-01-21 22:46:51 -05:00 committed by Diane Fleming
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<?xml version="1.0" encoding="utf-8"?>
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0"
xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
xml:id="module001-ch007-keystone-arch">
<title>Keystone Architecture</title>
<para>More Content To be Added ...</para>
<para><guilabel>Identity Service Concepts</guilabel></para>
<para>The Identity service performs the following
<!--<para>More Content To be Added ...</para>
<section xml:id="module001-ch007-keystone-arch-concepts">
<title>Identity Service Concepts</title> -->
<para>The Identity service performs these
functions:</para>
<itemizedlist>
<listitem>
@ -20,163 +19,212 @@
services with their API endpoints.</para>
</listitem>
</itemizedlist>
<para>To understand the Identity Service, you must understand the
following concepts:</para>
<para><guilabel>User</guilabel></para>
<para>Digital representation of a person, system, or service who
uses OpenStack cloud services. Identity authentication
services will validate that incoming request are being made by
the user who claims to be making the call. Users have a login
and may be assigned tokens to access resources. Users may be
directly assigned to a particular tenant and behave as if they
are contained in that tenant.</para>
<para><guilabel>Credentials</guilabel></para>
<para>Data that is known only by a user that proves who they
are. In the Identity Service, examples are:</para>
<itemizedlist>
<para>To understand the Identity Service, you must understand these concepts:</para>
<variablelist wordsize="10">
<varlistentry>
<term><emphasis role="bold">User</emphasis></term>
<listitem>
<para>Username and password</para>
<para>Digital representation of a person, system, or service
who uses OpenStack cloud services. Identity authentication
services will validate that incoming request are being
made by the user who claims to be making the call. Users
have a login and may be assigned tokens to access
resources. Users may be directly assigned to a particular
tenant and behave as if they are contained in that
tenant.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Credentials</emphasis></term>
<listitem>
<para>Username and API key</para>
<para>Data that is known only by a user that proves who they
are. In the Identity Service, examples are:</para>
<itemizedlist>
<listitem>
<para>Username and password</para>
</listitem>
<listitem>
<para>Username and API key</para>
</listitem>
<listitem>
<para>An authentication token provided by the Identity
Service</para>
</listitem>
</itemizedlist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Authentication</emphasis></term>
<listitem>
<para>An authentication token provided by the Identity
Service</para>
<para>The act of confirming the identity of a user. The
Identity Service confirms an incoming request by
validating a set of credentials supplied by the user.
These credentials are initially a username and password or
a username and API key. In response to these credentials,
the Identity Service issues the user an authentication
token, which the user provides in subsequent
requests.</para>
</listitem>
</itemizedlist>
<para><guilabel>Authentication</guilabel></para>
<para>The act of confirming the identity of a user. The Identity
Service confirms an incoming request by validating a set of
credentials supplied by the user. These credentials are
initially a username and password or a username and API key.
In response to these credentials, the Identity Service issues
the user an authentication token, which the user provides in
subsequent requests.</para>
<para><guilabel>Token</guilabel></para>
<para>An arbitrary bit of text that is used to access resources.
Each token has a scope which describes which resources are
accessible with it. A token may be revoked at anytime and is
valid for a finite duration.</para>
<para>While the Identity Service supports token-based
authentication in this release, the intention is for it to
support additional protocols in the future. The intent is for
it to be an integration service foremost, and not aspire to be
a full-fledged identity store and management solution.</para>
<para><guilabel>Tenant</guilabel></para>
<para>A container used to group or isolate resources and/or
identity objects. Depending on the service operator, a tenant
may map to a customer, account, organization, or
project.</para>
<para><guilabel>Service</guilabel></para>
<para>An OpenStack service, such as Compute (Nova), Object
Storage (Swift), or Image Service (Glance). Provides one or
more endpoints through which users can access resources and
perform operations.</para>
<para><guilabel>Endpoint</guilabel></para>
<para>An network-accessible address, usually described by URL,
from where you access a service. If using an extension for
templates, you can create an endpoint template, which
represents the templates of all the consumable services that
are available across the regions.</para>
<para><guilabel>Role</guilabel></para>
<para>A personality that a user assumes that enables them to
perform a specific set of operations. A role includes a set of
rights and privileges. A user assuming that role inherits
those rights and privileges.</para>
<para>In the Identity Service, a token that is issued to a user
includes the list of roles that user can assume. Services that
are being called by that user determine how they interpret the
set of roles a user has and which operations or resources each
role grants access to.</para>
<figure>
<title>Keystone Authentication</title>
<mediaobject>
<imageobject>
<imagedata fileref="figures/image19.png"/>
</imageobject>
</mediaobject>
</figure>
<para><guilabel>User management</guilabel></para>
<para>The main components of Identity user management are:</para>
<itemizedlist>
<listitem>
<para>Users</para>
</listitem>
<listitem>
<para>Tenants</para>
</listitem>
<listitem>
<para>Roles</para>
</listitem>
</itemizedlist>
<para>A userrepresents a human user, and has associated
information such as username, password and email. This example
creates a user named "alice":</para>
<para>$ keystone user-create --name=alice --pass=mypassword123
--email=alice@example.com</para>
<para>A tenantcan be a project, group, or organization. Whenever
you make requests to OpenStack services, you must specify a
tenant. For example, if you query the Compute service for a list
of running instances, you will receive a list of all of the
running instances in the tenant you specified in your query.
This example creates a tenant named "acme":</para>
<para>$ keystone tenant-create --name=acmeA rolecaptures what
operations a user is permitted to perform in a given tenant.
This example creates a role named "compute-user":</para>
<para>$ keystone role-create --name=compute-userThe Identity
service associates a user with a tenant and a role. To continue
with our previous examples, we may wish to assign the "alice"
user the "compute-user" role in the "acme" tenant:</para>
<para>$ keystone user-list</para>
<para>$ keystone user-role-add --user=892585 --role=9a764e
--tenant-id=6b8fd2</para>
<para>A user can be assigned different roles in different tenants:
for example, Alice may also have the "admin" role in the
"Cyberdyne" tenant. A user can also be assigned multiple roles
in the same tenant.</para>
<para>The /etc/[SERVICE_CODENAME]/policy.json controls what users
are allowed to do for a given service. For example,
/etc/nova/policy.json specifies the access policy for the
Compute service, /etc/glance/policy.json specifies the access
policy for the Image service, and /etc/keystone/policy.json
specifies the access policy for the Identity service.</para>
<para>The default policy.json files in the Compute, Identity, and
Image service recognize only the admin role: all operations that
do not require the admin role will be accessible by any user
that has any role in a tenant.</para>
<para>If you wish to restrict users from performing operations in,
say, the Compute service, you need to create a role in the
Identity service and then modify /etc/nova/policy.json so that
this role is required for Compute operations.</para>
<para>For example, this line in /etc/nova/policy.json specifies
that there are no restrictions on which users can create
volumes: if the user has any role in a tenant, they will be able
to create volumes in that tenant.</para>
<para><guilabel>Service Management</guilabel></para>
<para>The Identity Service provides the following service
management functions:</para>
<itemizedlist>
<listitem>
<para>Services</para>
</listitem>
<listitem>
<para>Endpoints</para>
</listitem>
</itemizedlist>
<para>The Identity Service also maintains a user that corresponds
to each service (such as, a user named nova, for the Compute
service) and a special service tenant, which is called
service.</para>
<para>The commands for creating services and endpoints are
described in a later section.</para>
</varlistentry>
<varlistentry>
<term>
<emphasis role="bold">Token</emphasis></term>
<listitem>
<para>An arbitrary bit of text that is used to access
resources. Each token has a scope which describes which
resources are accessible with it. A token may be revoked
at anytime and is valid for a finite duration.</para>
<para>While the Identity Service supports token-based
authentication in this release, the intention is for it to
support additional protocols in the future. The intent is
for it to be an integration service foremost, and not
aspire to be a full-fledged identity store and management
solution.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Tenant</emphasis></term>
<listitem>
<para>A container used to group or isolate resources and/or
identity objects. Depending on the service operator, a
tenant may map to a customer, account, organization, or
project.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<emphasis role="bold">Service</emphasis></term>
<listitem>
<para>An OpenStack service, such as Compute (Nova), Object
Storage (Swift), or Image Service (Glance). Provides one
or more endpoints through which users can access resources
and perform operations.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Endpoint</emphasis></term>
<listitem>
<para>An network-accessible address, usually described by
URL, from where you access a service. If using an
extension for templates, you can create an endpoint
template, which represents the templates of all the
consumable services that are available across the
regions.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Role</emphasis></term>
<listitem>
<para>A personality that a user assumes that enables them to
perform a specific set of operations. A role includes a
set of rights and privileges. A user assuming that role
inherits those rights and privileges.</para>
<para>In the Identity Service, a token that is issued to a
user includes the list of roles that user can assume.
Services that are being called by that user determine how
they interpret the set of roles a user has and which
operations or resources each role grants access to.</para>
<figure>
<title>Keystone Authentication</title>
<mediaobject>
<imageobject>
<imagedata fileref="figures/image19.png" contentwidth="4in" scale="50" width="4in"/>
</imageobject>
</mediaobject>
</figure>
</listitem>
</varlistentry>
<varlistentry>
<term>
<emphasis role="bold">User management</emphasis></term>
<listitem>
<para>The main components of Identity user management
are:</para>
<itemizedlist>
<listitem>
<para>Users</para>
</listitem>
<listitem>
<para>Tenants</para>
</listitem>
<listitem>
<para>Roles</para>
</listitem>
</itemizedlist>
<para>A user represents a human user, and has associated
information such as username, password and email. This
example creates a user named "alice":</para>
<screen><prompt>$</prompt> <userinput>keystone user-create --name=alice --pass=mypassword123 --email=alice@example.com</userinput></screen>
<para>A tenant can be a project, group, or organization.
Whenever you make requests to OpenStack services, you must
specify a tenant. For example, if you query the Compute
service for a list of running instances, you get a list of
all running instances for the specified tenant. This
example creates a tenant named "acme":</para>
<screen><prompt>$</prompt> <userinput>keystone tenant-create --name=acme</userinput></screen>
<para>A role captures what operations a user is permitted to
perform in a given tenant. This example creates a role
named "compute-user":</para>
<screen><prompt>$</prompt> <userinput>keystone role-create --name=compute-user</userinput></screen>
<para>The Identity service associates a user with a tenant
and a role. To continue with our previous examples, we may
wish to assign the "alice" user the "compute-user" role in
the "acme" tenant:</para>
<screen><prompt>$</prompt> <userinput>keystone user-list</userinput></screen>
<screen><prompt>$</prompt> <userinput>keystone user-role-add --user=892585 --role=9a764e --tenant-id=6b8fd2</userinput></screen>
<para>A user can be assigned different roles in different
tenants. For example, Alice may also have the "admin" role
in the "Cyberdyne" tenant. A user can also be assigned
multiple roles in the same tenant.</para>
<para>The
<filename>/etc/[SERVICE_CODENAME]/policy.json</filename>
file controls what users are allowed to do for a given
service. For example,
<filename>/etc/nova/policy.json</filename> specifies the
access policy for the Compute service,
<filename>/etc/glance/policy.json</filename> specifies
the access policy for the Image service, and
<filename>/etc/keystone/policy.json</filename> specifies
the access policy for the Identity service.</para>
<para>The default policy.json files in the Compute,
Identity, and Image service recognize only the admin role:
all operations that do not require the admin role will be
accessible by any user that has any role in a
tenant.</para>
<para>If you wish to restrict users from performing
operations in, say, the Compute service, you need to
create a role in the Identity service and then modify
<filename>/etc/nova/policy.json</filename> so that this
role is required for Compute operations.</para>
<para>For example, this line in
<filename>/etc/nova/policy.json</filename> specifies
that there are no restrictions on which users can create
volumes: if the user has any role in a tenant, they will
be able to create volumes in that tenant.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Service
Management</emphasis></term>
<listitem>
<para>The Identity Service provides the following service
management functions:</para>
<itemizedlist>
<listitem>
<para>Services</para>
</listitem>
<listitem>
<para>Endpoints</para>
</listitem>
</itemizedlist>
<para>The Identity Service also maintains a user that
corresponds to each service, such as a user named nova,
for the Compute service) and a special service tenant,
which is called service.</para>
<para>The commands for creating services and endpoints are
described in a later section.</para>
</listitem>
</varlistentry>
</variablelist>
<!-- </section>-->
</chapter>