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Pentaho Documentation

Use Secure Impersonation to Access a Cloudera Cluster

This article explains how to configure the Pentaho Server to connect to a Cloudera Hadoop 5.7 cluster to use secure impersonation. For an overview of secure impersonation, refer to Setting Up Big Data Security. The following sections will guide you through the setup and configuration process:

  • Prerequisites
  • Parameter Configuration
  • Configuring MapReduce Jobs (Windows-only)
  • Connecting to a Cloudera Impala Database

Prerequisites

The following requirements must be met to use secure impersonation:

  • The cluster must be secured with Kerberos, and the Kerberos server used by the cluster must be accessible to the Pentaho Server.
  • The Pentaho computer must have Kerberos installed and configured as explained in Set Up Kerberos for Pentaho.

If your system has version 8 of the Java Runtime Environment (JRE) or the Java Developer's Kit (JDK) installed, you will not need to install the Kerberos client, since it is included in the Java installation. You will need to modify the Kerberos configuration file, krb5.conf, as specified in the Set Up Kerberos for Pentaho topic.

Follow the instructions below for editing the config.properties file below instead of the instructions in the Edit config.properties (Secured Clusters) section of the Set up Pentaho to Connect to a Cloudera Cluster article.

Parameter Configuration

The mapping types value in the config.properties file turns secure impersonation on or off. The mapping types supported by the Pentaho Server are disabled and simple. When set to disabled or left blank, the Pentaho Server does not use authentication. When set to simple, the Pentaho users can connect to the Hadoop cluster as a proxy user. To configure the cluster for secure impersonation, stop the Pentaho Server and complete the following steps:

  1. Navigate to the pentaho-server\pentaho-solutions\system\kettle\plugins\pentaho-big-data-plugin\hadoop-configurations\chd57  folder and open the config.properties file with a text editor.
  2. Modify the config.properties file with the values in the table below. If you have key-value pairs in your existing config.properties file that are not security related, merge those settings into the file.
Parameter Value
pentaho.authentication.default.kerberos.principal exampleUser@EXAMPLE.COM
pentaho.authentication.default.kerberos.keytabLocation Set the Kerberos keytab. You only need to set the password or the keytab, not both.
pentaho.authentication.default.kerberos.password Set the Kerberos password.  You only need to set the password or the keytab, not both.
pentaho.authentication.default.mapping.impersonation.type simple
pentaho.authentication.default.mapping.server.credentials.kerberos.principal exampleUser@EXAMPLE.COM
pentaho.authentication.default.mapping.server.credentials.kerberos.keytabLocation You only need to set the password or the keytab, not both.
pentaho.authentication.default.mapping.server.credentials.kerberos.password You only need to set the password or the keytab, not both.
pentaho.oozie.proxy.user Add the proxy user's name if you plan to access the Oozie service through a proxy.  Otherwise, leave it set to oozie.
  1. Save and close the config.properties file.
  2. Copy the config.properties file to the following folders:

    design-tools/report-designer/plugins/pentaho-big-data-plugin/hadoop-configurations/cdh57/config.properties
    design-tools/metadata-editor/plugins/pentaho-big-data-plugin/hadoop-configurations/cdh57/config.properties
    design-tools/data-integration/plugins/pentaho-big-data-plugin/hadoop-configurations/cdh57/config.properties

  3. Restart the Pentaho Server.

Configuring MapReduce Jobs

For Windows systems you must modify the mapred-site.xml files to run MapReduce jobs with secure impersonation. Complete the following steps to modify the files:

  1. Navigate to the design-tools\data-integration\plugins\pentaho-big-data-plugin\hadoop-configurations\cdh57 folder and open the mapred-site.xml file with a text editor.
  2. Navigate to the pentaho-server\pentaho-solutions\system\kettle\plugins\pentaho-big-data-plugin\hadoop-configurations\cdh57 folder and open the mapred-site.xml file with a text editor.
  3. Add the following two properties to the two mapred-site.xml files:
  <property>
    <name>mapreduce.app-submission.cross-platform</name>
    <value>true</value>
  </property>
  <property>
    <name>mapreduce.framework.name</name>
    <value>yarn</value>
  </property>
  1. Save and close the files.

Connecting to a Cloudera Impala Database

Complete the following steps to connect to a secure Cloudera Impala database:

  1. Download the Cloudera Impala JDBC driver for your operating system from the Cloudera web site http://www.cloudera.com/downloads/connectors/impala/jdbc/2-5-29.html.

Secure impersonation with Impala is only supported with the Cloudera Impala JDBC driver. You may have to create an account with Cloudera to download the driver file.

  1. Extract the ImpalaJDBC41.jar file from the downloaded zip file into the folder pentaho-server/pentaho-solution/system/kettle/plugins/pentaho-big-data-plugin/hadoop-configurations/cdh57/lib. The ImpalaJDBC41.jar file is the only file to extract from the downloaded file.
  2. Connect to a secure CDH cluster. If you have not set up a secure cluster, complete the procedure in the article Set up Pentaho to Connect to a Cloudera Cluster to set up a secure cluster.
  3. Start the PDI Client (Spoon) and choose File > New > Transformation to add a new transformation.
  4. Click the View tab, then right-click Database Connections and choose New.
  5. In the Database Connection dialog box enter the values from the following table:
Field Value
Connection Name text box User-defined name
Connection Type pane Cloudera Impala
Host Name text box Hostname
Database Name text box default
Port Number text box 21050
  1. Click Options in the left pane of the Database Connection dialog box and enter the parameter values as shown in the following table:
Parameter  Value
KrbHostFQDN The fully qualified domain name of the Impala host.
KrbServiceName The service principal name of the Impala server.
KrbRealm The Kerberos realm used by the cluster.
  1. Click Test when your settings are entered. A success message appears if everything was entered correctly.

Once you have saved your changes in the repository, you can run your transformation from the Pentaho Server. Secure impersonation from the PDI Client is not currently supported.