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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="mixed_security">

  <title>Using Multiple Authentication Methods with Impala</title>
  <prolog>
    <metadata>
      <data name="Category" value="Security"/>
      <data name="Category" value="Impala"/>
      <data name="Category" value="Authentication"/>
      <data name="Category" value="Kerberos"/>
      <data name="Category" value="LDAP"/>
      <data name="Category" value="Administrators"/>
    </metadata>
  </prolog>

  <conbody>

    <p>
      Impala 2.0 and later automatically handles both Kerberos and LDAP authentication. Each
      <cmdname>impalad</cmdname> daemon can accept both Kerberos and LDAP requests through the same port. No
      special actions need to be taken if some users authenticate through Kerberos and some through LDAP.
    </p>

    <p>
      Prior to Impala 2.0, you had to configure each <cmdname>impalad</cmdname> to listen on a specific port
      depending on the kind of authentication, then configure your network load balancer to forward each kind of
      request to a DataNode that was set up with the appropriate authentication type. Once the initial request was
      made using either Kerberos or LDAP authentication, Impala automatically handled the process of coordinating
      the work across multiple nodes and transmitting intermediate results back to the coordinator node.
    </p>

<!--
    <p>
    This technique is most suitable for larger clusters, where
    you are already using load balancing software for high availability.
    You configure Impala to run on a different port on the nodes configured for LDAP.
    Then you configure the load balancing software to forward Kerberos
    connection requests to nodes using the default port, and LDAP connection requests
    to nodes using an alternative port for LDAP.
    Consult the documentation for your load balancing software for how to
    configure that type of forwarding.
    </p>
-->
  </conbody>
</concept>