Hue is a suite of applications that provide web-based access to CDH components and a platform for building custom applications.
The following figure illustrates how Hue works. Hue Server is a "container" web application that sits in between your CDH installation and the browser. It hosts the Hue applications and communicates with various servers that interface with CDH components.
The Hue Server uses a database to manage session, authentication, and Hue application data. For example, the Job Designer application stores job designs in the database.
In a CDH cluster, the Hue Server runs on a special node. For optimal performance, this should be one of the nodes within your cluster, though it can be a remote node as long as there are no overly restrictive firewalls. For small clusters of less than 10 nodes, you can use your existing master node as the Hue Server. In a pseudo-distributed installation, the Hue Server runs on the same machine as the rest of your CDH services.