Configuring Secure HBase Replication

Scenario

This topic provides the procedure to configure the secure HBase replication during cross-realm Kerberos setup in security mode.

Prerequisites

Mapping for all the FQDNs to their realms should be defined in the Kerberos configuration file.
The passwords and keytab files of ONE.COM and TWO.COM must be the same.

Procedure

Create krbtgt principals for the two realms.

For example, if you have two realms called ONE.COM and TWO.COM, you need to add the following principals: krbtgt/ONE.COM@TWO.COM and krbtgt/TWO.COM@ONE.COM.

Add these two principals at both realms.
```
kadmin: addprinc -e "<enc_type_list>" krbtgt/ONE.COM@TWO.COM
kadmin: addprinc -e "<enc_type_list>" krbtgt/TWO.COM@ONE.COM
```
There must be at least one common keytab mode between these two realms.
Add rules for creating short names in Zookeeper.
Dzookeeper.security.auth_to_local is a parameter of the ZooKeeper server process. Following is an example rule that illustrates how to add support for the realm called ONE.COM. The principal has two members (such as service/instance@ONE.COM).
```
Dzookeeper.security.auth_to_local=RULE:[2:\$1@\$0](.*@\\QONE.COM\\E$)s/@\\QONE.COM\\E$//DEFAULT
```
The above code example adds support for the ONE.COM realm in a different realm. Therefore, in the case of replication, you must add a rule for the master cluster realm in the slave cluster realm. DEFAULT is for defining the default rule.
Add rules for creating short names in the Hadoop processes.

The following is the hadoop.security.auth_to_local property in the core-site.xml file in the slave cluster HBase processes. For example, to add support for the ONE.COM realm:
```
<property>
<name>hadoop.security.auth_to_local</name>
<value>RULE:[2:$1@$0](.*@\QONE.COM\E$)s/@\QONE.COM\E$//DEFAULT</value>
</property>
```
If replication for bulkload data is enabled, then the same property for supporting the slave realm needs to be added in the core-site.xml file in the master cluster HBase processes.

Example:
```
<property>
<name>hadoop.security.auth_to_local</name>
<value>RULE:[2:$1@$0](.*@\QTWO.COM\E$)s/@\QTWO.COM\E$//DEFAULT</value>
</property>
```