Creating a connection to HCatalog - 7.1

Talend Big Data Studio User Guide

Talend Big Data
Talend Studio
Design and Development


  1. Expand Hadoop cluster node under Metadata node in the Repository tree view, right-click the Hadoop connection to be used and select Create HCatalog from the contextual menu.
  3. Click Next when completed. The second step requires you to fill in the HCatalog connection data. Among the properties, Host name is automatically pre-filled with the value inherited from the Hadoop connection you selected in the previous steps. The Templeton Port and the Database are using the default values.
    This database is actually a Hive database and Templeton (WebHcat) is used as a REST-like web API by HCatalog to issue commands. For further information about Templeton (WebHcat), see Apache's documentation on
    The Principal and the Realm fields are displayed only when the Hadoop connection you are using enables the Kerberos security. They are the properties required by Kerberos to authenticate the HCatalog client and the HCatalog server to each other.

    In order to make the host name of the Hadoop server recognizable by the client and the host computers, you have to establish an IP address/hostname mapping entry for that host name in the related hosts files of the client and the host computers. For example, the host name of the Hadoop server is talend-all-hdp, and its IP address is 192.168.x.x, then the mapping entry reads 192.168.x.x talend-all-hdp. For the Windows system, you need to add the entry to the file C:\WINDOWS\system32\drivers\etc\hosts (assuming Windows is installed on drive C). For the Linux system, you need to add the entry to the file /etc/hosts.

  4. If necessary, change these default values to those of the port and the database used by the HCatalog you connect to.
  5. If required, enter the Principal and the Realm properties.
  6. If you need to use custom configuration for the Hadoop or HCatalog distribution to be used, click the [...] button next to Hadoop properties to open the properties table and add the property or properties to be customized. Then at runtime, these changes will override the corresponding default properties used by the Studio for its Hadoop engine.
    For further information about the properties of Hadoop, see Apache's Hadoop documentation on, or the documentation of the Hadoop distribution you need to use. For example, the following page lists some of the default Hadoop properties:
    For further information about the properties of HCatalog, see Apache's documentation for HCatalog. For example, the following page describes some of the HCatalog configuration properties:
  7. Click Check to test the connection you have just defined. A message pops up to indicate whether the connection is successful.
  8. Click Finish to validate these changes.
    The created HCatalog connection is available under the Hadoop cluster node in the Repository tree view.






  9. Right-click the newly created connection, and select Retrieve schema from the drop-down list in order to load the desired table schema from the established connection.