Connecting to HBase in a Kerberos Enabled Cluster

This article will show a step by step guide on how to connect to HBase in an a Kerberos enable cluster. If you need to setup a cluster that have Kerberos enabled, this is a good guid to follow.

Clone Example Project

This article will be based on this project. Please run the following to clone the project.

$ git clone https://github.com/jjmeyer0/hdp-test-examples

Creating Keytab

Before getting into the code, it is important to generate necessary files. If a key tab is not available follow the steps below to create one. In the example below, a key tab for the user jj and realm EXAMPLE.COM is created. The below commands should be run on one of the nodes in the cluster.

$ kadmin.local
$ addprinc jj@EXAMPLE.COM
$ <CTRL-D>
$ ktutil
$ addent -password -p jj -k 1 -e RC4-HMAC
$ wkt jj.keytab
$ q

Preparing User in HBase

The user that was used above must be given correct permissions in HBase. To do so do the following:

$ hbase shell
hbase(main):001:0> grant 'jj', 'RW'

Obtaining Necessary Files

This example also expects the files listed below. Below is a walkthrough on how to copy the necessary files from the cluster to local.

• hbase-site.xml
• <username>.keytab
• krb5.conf

$ scp -i <insecure_private_key> vagrant@c6401:/etc/krb5.conf .
$ scp -i <insecure_private_key> vagrant@c6401:/etc/hbase/conf/hbase-site.xml .
$ scp -i <insecure_private_key> root@c6401:~/jj.keytab .


Once the files have been obtained, please move them to the following directory.

src/main/resources/

For testing, it is recommended to change 'hbase.client.retries.number' property in hbase-site.xml. By default it is 35. This is quite high when running some tests.

Code Walkthrough

The First thing that needs to be done is to create and load the HBase configuration.

// Setting up the HBase configuration
Configuration configuration = new Configuration();
configuration.addResource("src/main/resources/hbase-site.xml");

Next point to the krb5.conf file and setup the kerberos principal and keytab.

// Point to the krb5.conf file.
System.setProperty("java.security.krb5.conf", "src/main/resources/krb5.conf");
System.setProperty("sun.security.krb5.debug", "true");

// Override these values by setting -DkerberosPrincipal and/or -DkerberosKeytab
String principal = System.getProperty("kerberosPrincipal", "jj@EXAMPLE.COM");
String keytabLocation = System.getProperty("kerberosKeytab", "src/main/resources/jj.keytab");

Now login with the principal and keytab defined above.

UserGroupInformation.setConfiguration(configuration);
UserGroupInformation.loginUserFromKeytab(principal, keytabLocation)


Please see this file for full example. A Scala version can be found here.

Resources

1. Ambari Quickstart Guide
2. Full Code (This article covers HBase examples)