Basic Components of the Apple Qmaster Distributed Processing System

Although the Apple Qmaster software includes a few different applications (see The Interfaces), as a whole it is part of a networked system that includes the following basic components.

The client computer, the service nodes, and the cluster controller are often on separate (but network-connected) computers, for the most rapid processing potential. However, the cluster controller could be on a client computer or a service node. See Using One Computer to Serve Two Distributed Processing Roles for more information on this scenario.

Following is a closer look at the part each component plays in the Apple Qmaster system.


Batches are submitted for distributed processing from the client computers. A client computer can be any computer that has Compressor or Apple Qmaster installed and is on the same network (subnet) as the cluster controller. Multiple client computers can be on the same subnet, using the same cluster to do the processing for various applications.

You use Compressor or the Apple Qmaster application to submit batches to be processed for a client. See the Compressor User Manual and the Apple Qmaster User Manual for details on using these applications.

Note: On any given Final Cut Studio system or network, the Compressor and Apple Qmaster versions (numbers) and the version of QuickTime must all match. For example, Compressor 3.0.5 will work only with the 3.0.5 version of Apple Qmaster, and no other version. In this example, the correct version of QuickTime is QuickTime 7.5.5 or later. Non-matching configurations are not supported.


When a client sends batches to the Apple Qmaster distributed processing system, all the processing and subsequent moving of any output files is performed by a group of Apple Qmaster–configured computers called a cluster. You can create one or more clusters of service nodes, with one cluster controller included in each cluster. Each computer in the cluster is connected to the other computers in the cluster through a network connection.

Figure. Diagram showing the Apple Qmaster cluster including one cluster controller and three service nodes.

Note: This illustration provides only one simple example of a cluster. Other possibilities are described in Preparing a Network for Distributed Processing.

Service Nodes

The service nodes are where the processing work is done. When you assign a group of service nodes to a cluster, they function as one very powerful computer because all their resources are shared. If one service node is overloaded or otherwise inaccessible, another service node is used.

You make a computer available as a service node by configuring it in the Apple Qmaster pane of System Preferences. The simple steps involved in using System Preferences to configure a service node are described in Administering Clusters.

Note: The terms processing and rendering will come up frequently as you read this document. The term processing is used here in a general way to cover both rendering (for Shake and other frame-based rendering applications) and encoding (or transcoding or compression) for Compressor. For more information, see the Shake User Manual and the Compressor User Manual.

Cluster Controllers

The cluster controller software acts as the manager of a cluster. The cluster controller directs the distribution of batches within the cluster. It has the ability to determine the best use of the cluster resources based on work and availability variables. (See How the Apple Qmaster System Distributes Batches for more details.) The cluster controller is responsible for accepting batch submissions, maintaining and managing the batch queue, and doling out the work to the appropriate service node. It also tracks the status of all outstanding batches.

You make a computer available as a cluster controller by turning on the cluster–controlling service in the Apple Qmaster pane of System Preferences.