docs/topics/impala_delegation.xml

<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept rev="1.2" id="delegation">

  <title>Configuring Impala Delegation for Hue and BI Tools</title>

  <prolog>
    <metadata>
      <data name="Category" value="Security"/>
      <data name="Category" value="Impala"/>
      <data name="Category" value="Authentication"/>
      <data name="Category" value="Delegation"/>
      <data name="Category" value="Hue"/>
      <data name="Category" value="Administrators"/>
      <data name="Category" value="Developers"/>
      <data name="Category" value="Data Analysts"/>
    </metadata>
  </prolog>

  <conbody>

    <p>
<!--
      When users connect to Impala directly through the <cmdname>impala-shell</cmdname> interpreter, the Sentry
      authorization framework determines what actions they can take and what data they can see.
-->
      When users submit Impala queries through a separate application, such as Hue or a business intelligence tool,
      typically all requests are treated as coming from the same user. In Impala 1.2 and higher, authentication is
      extended by a new feature that allows applications to pass along credentials for the users that connect to
      them (known as <q>delegation</q>), and issue Impala queries with the privileges for those users. Currently,
      the delegation feature is available only for Impala queries submitted through application interfaces such as
      Hue and BI tools; for example, Impala cannot issue queries using the privileges of the HDFS user.
    </p>

    <p>
      The delegation feature is enabled by a startup option for <cmdname>impalad</cmdname>:
      <codeph>--authorized_proxy_user_config</codeph>. When you specify this option, users whose names you specify
      (such as <codeph>hue</codeph>) can delegate the execution of a query to another user. The query runs with the
      privileges of the delegated user, not the original user such as <codeph>hue</codeph>. The name of the
      delegated user is passed using the HiveServer2 configuration property <codeph>impala.doas.user</codeph>.
    </p>

    <p>
      You can specify a list of users that the application user can delegate to, or <codeph>*</codeph> to allow a
      superuser to delegate to any other user. For example:
    </p>

<codeblock>impalad --authorized_proxy_user_config 'hue=user1,user2;admin=*' ...</codeblock>

    <note>
      Make sure to use single quotes or escape characters to ensure that any <codeph>*</codeph> characters do not
      undergo wildcard expansion when specified in command-line arguments.
    </note>

    <p>
      See <xref href="impala_config_options.xml#config_options"/> for details about adding or changing
      <cmdname>impalad</cmdname> startup options. See
      <xref keyref="how-hiveserver2-brings-security-and-concurrency-to-apache-hive">this
      blog post</xref> for background information about the delegation capability in HiveServer2.
    </p>
    <p>
      To set up authentication for the delegated users:
    </p>

    <ul>
      <li>
        <p>
          On the server side, configure either user/password authentication through LDAP, or Kerberos
          authentication, for all the delegated users. See <xref href="impala_ldap.xml#ldap"/> or
          <xref href="impala_kerberos.xml#kerberos"/> for details.
        </p>
      </li>

      <li>
        <p>
          On the client side, to learn how to enable delegation, consult the documentation
          for the ODBC driver you are using.
        </p>
      </li>
    </ul>

  </conbody>

</concept>