Configuring the HTTP Binding Component for Clustering

For the most part, configuring the HTTP Binding Component for clustering is handled by Sun Java System Application Server (GlassFish). The HTTP Binding Component is a pre-installed component in the application server. Default HTTP and HTTPS port numbers are calculated and pre-assigned when the binding components are installed in the server instances. A web service, serviced by an HTTP Binding Component, is identified by a unique URL identifier with the structure: "http://<hostname>:<port>/<context> ".

Each component instance in the cluster must have exclusive access to the resource, therefore a unique port number is assigned to each component instance. A predefined token name is used in the WSDL artifact to resolve the actual port value when the component is deployed into each instance.

Predefined HTTP Port Tokens

Predefined token names:

• "${HttpDefaultPort}" for the HTTP port

• "${HttpsDefaultPort}" for the HTTPS port

These token names are used in lieu of a real port number in the endpoint URL (soap:address) to allow the application client to direct HTTP requests to the default port. The value of the token is then resolved by the HTTP Binding Component, based on the configured default values when an application is deployed.

If you reinstall an HTTP Binding Component, you must reconfigure the default ports properly for each component instance.

Understanding the ${HttpDefaultPort} Token

The following section provides a little background on the ${HttpDefaultPort} token and how it's resolved when an application is deployed.

Just like the GlassFish web services, which are always deployed to a designated HTTP port (8080 is the configured default), the HTTP Binding Component also has a default HTTP port to which web services are deployed. Since the HTTP Binding Component comes with GlassFish as a pre-installed component, a default HTTP port is always assigned to it. The default port is configured in the JBI Runtime module during the installation of GlassFish, at which time it allocates an available port for each HTTP Binding Component instance in the GlassFish domain(s).

Originally, this default port setting and the ${HttpDefaultPort} token were placed in the WSDL URL to support clustering, where multiple HTTP BC instances could be running on the same machine. As such, when an application is deployed, the port token is used to resolve the actual port value to the assigned port in each instance, with no chance of port collisions.

Since then, the use of the port has evolved such that the HTTP Binding Component (the web service container in JBI) acts in a fashion that is similar to the GlassFish web service container. When an application “arrives“ in the binding component, it looks up its default HTTP port setting, and replace the token in the URL with the actual port number. If the default port number is not configured, an Initialization failed exception is thrown.