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