This is the documentation for Cloudera 5.2.x.
Documentation for other versions is available at Cloudera Documentation.

Installing Impala

Cloudera Impala is included with CDH 5. To use Cloudera Impala with CDH 4, you must install both CDH and Impala on the hosts that will run Impala.
  Note:

Installing Impala after Upgrading Cloudera Manager

If you have just upgraded Cloudera Manager from a version that did not support Impala, the Impala software is not installed automatically. (Upgrading Cloudera Manager does not automatically upgrade CDH or other managed services). You can add Impala using parcels; go to the Hosts tab, and select the Parcels tab. You should see at least one Impala parcel available for download. See Parcels for detailed instructions on using parcels to install or upgrade Impala. If you do not see any Impala parcels available, click the Edit Settings button on the Parcels page to go to the Parcel configuration settings and verify that the Impala parcel repo URL (http://archive.cloudera.com/impala/parcels/latest/) has been configured in the Parcels configuration page. See Parcel Configuration Settings for more details.

Post Installation Configuration

See The Impala Service for instructions on configuring the Impala service.