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This document describes how to set up a Trifacta® user in Kerberos.

Pre-requisites for Kerberos integration

Before you begin, please verify the following:

  1. The [hadoop.user (default=trifacta)] user is created and enabled on each node in the Hadoop cluster.

    NOTE: If LDAP is enabled, the trifacta should be created in the same realm as the cluster.

  2. On the Trifacta host, the directory /opt/trifacta is owned by the [hadoop.user] user.

  3. The [hadoop.user] user exists on each node in the Hadoop cluster.

    NOTE: The [hadoop.user] must have the same user ID and group ID on each node in the cluster. Depending on your cluster's configuration, this requirement may require an LDAP command. Configuring LDAP is beyond the scope of this document.

  4. The [hadoop.user] user must be a member of any special group that is permitted to access HDFS or to run Hadoop jobs.

Configure the KDC

Steps:

  1. On your KDC node, configure a Kerberos principal for the Trifacta platform:
    1. The principal's identifier has two parts: its name and its realm. For example, the principal trifacta@HADOOPVAL.MSSVC.LOCAL has the name trifacta and the realm HADOOPVAL.MSSVC.LOCAL
    2. Retain the name and principal for later configuration.
  2. Create a keytab file for the Trifacta principal. Command:

    kadmin xst -k trifacta.keytab <full principal identifier>

    where:
    <full_principal_identifier> is the principal identifier in Kerberos. 

    On the KDC, you may have to run kadmin.local instead of kadmin. The rest of the arguments should remain the same.

    NOTE: If you're creating a keytab file in an AD environment, alternative instructions may need to be applied. See below.

  3. Verify that the keytab is working. Command:

    klist -e -k -t trifacta.keytab
  4. Copy the keytab to the Trifacta node in the following directory: 
    /opt/trifacta/conf/trifacta.keytab
  5. Configure the keytab file so that it is owned by the [hadoop.user] user. It should only be readable by that user.

    NOTE: Verify that all user principals that use the platform are also members of the group of the keytab user.

Create keytab in Active Directory environments

Some additional instructions are provided for the following environments.

For MIT Kerberos

See https://kb.iu.edu/d/aumh:

> ktutil
  ktutil:  addent -password -p username@EXAMPLE.COM -k 1 -e rc4-hmac
  Password for username@EXAMPLE.COM: [enter your password]
  ktutil:  addent -password -p username@EXAMPLE.COM -k 1 -e aes256-cts
  Password for username@EXAMPLE.COM: [enter your password]
  ktutil:  wkt username.keytab
  ktutil:  quit 

For Hiemdal Kerberos

  > ktutil -k username.keytab add -p username@EXAMPLE.COM -e arcfour-hmac-md5 -V 1

If the keytab created in Heimdal does not work, you may need an aes256-cts entry. In this case, locate a machine with MIT Kerberos, and use the MIT Kerberos method instead.

Enable use of Kerberos keytab by Command Line Interface

The Trifacta Command Line Interface can reference a Kerberos keytab file to enable access to the platform without supplying passwords. After you have created the keytab, please complete the following steps.

NOTE: You must create a separate keytab file for the CLI. This keytab file must be created for the platform user that is connecting to the platform through the CLI, which is different from the [hadoop.user] user keytab that is used by the platform to connect to the cluster.

 

Steps:

  1. Export the following environment variables, where username corresponds to the user ID that is to be used to connect to the platform:

    export KRB5_CLIENT_KTNAME=/path/to/the/username.keytab
    export GSS_KRB5_NT_PRINCIPAL_NAME=username
  2. Invoke the command line interface commands without supplying a password parameter. For more information, see Command Line Interface.

Configure the Trifacta platform for Kerberos

You can apply this change through the Admin Settings Page (recommended) or trifacta-conf.json. For more information, see Platform Configuration Methods.

Locate the kerberos section, which controls Kerberos authentication.

Example configuration:

Substitute your own values in place of the example values as appropriate.

"kerberos.enabled": true,
"kerberos.principal": "trifacta",
"kerberos.kdc": "kdc.mssvc.local",
"kerberos.realm": "HADOOPVAL.MSSVC.LOCAL",
"kerberos.keytab": "/opt/trifacta/conf/trifacta.keytab"
"kerberos.principals.hive": "<UNUSED>",
"kerberos.principals.namenode": "nn/_HOST@EXAMPLE.COM"
"kerberos.principals.resourcemanager": "<YOUR_VALUE_HERE>",
ParameterDescription
enabledTo enable Kerberos authentication, set this value to true.
principalThe name part of the principal you created in the KDC
kdcThe host of the KDC
realmRealm of the KDC
keytab
Directory in the Trifacta deployment where the Kerberos keytab file is stored
principals

List of jobtrackers and namenodes that are governed by Kerberos

NOTE: kerberos.principals.hive is unused. This value must be inserted into the Hive connection definition. See Create Hive Connections.

NOTE: If you don't know the values to use here, see Set principal values below.

NOTE: If you don't specify principal names in the principals definition section, the default names are used: mapred/<jobtracker host>@<realm>. You should specify the principals explicitly.

At this point, you should be able to load files from HDFS and run jobs against the kerberized Hadoop cluster.

Set principal values for YARN

Check the following Hadoop config properties in yarn-site.xml:

principals.jobtracker = yarn.resourcemanager.principal
principals.namenode = dfs.namenode.kerberos.principal

Configure Kerberos-delegated relational connections

When Kerberos has been enabled in the platform, you can apply the global keytab to be used for SSO connections to relational sources of data. For more information, see Enable SSO for Relational Connections

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