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7.3: Redirecting servlets

7.3: Redirecting servlets

Servlet redirectors are used to direct requests from a Web server to one or more clones of a servlet engine in an application server.  WebSphere Application Server supports two mechanisms for redirecting HTTP requests to servlets:

  • Open Servlet Engine (OSE).  OSE is a proprietary mechanism for transporting data.  It can be used to direct client requests from the Web server to servlets on the same machine (local OSE) or on a remote machine (remote OSE).  OSE is fully integrated with WebSphere's modeling and cloning facility.
  • Servlet redirector.  A servlet redirector is a dedicated application server that is specifically designed to forward client requests to remote servlet engines.  The servlet redirector receives requests locally through OSE.  However, instead of processing them itself, it redirects them to other application servers.  The servlet redirector can be run in three different configurations:
    • The thick servlet redirector is configured on a machine that is a full WebSphere Application Server node with an administrative server.  It can be administered like any other application server.
    • The thick servlet redirector can also run with a simplified version of the administrative server known as an administrative agent. The administrative agent manages the servlet redirector, but it is controlled by a master administrative server on another node.
    • The thin servlet redirector runs without the administrative server. Special scripts are provided to manually start it and generate its configuration files.

Servlet redirection is generally used to scale up configurations that use a single servlet engine on a single machine to configurations that use multiple servlet engines on multiple machines.  Both servlet redirection mechanisms provide load balancing, failover support, and availability management for servlet engines. 

Go to previous article: Workload management for stand-alone Java clients Go to next article: OSE and remote OSE

 

 
Go to previous article: Workload management for stand-alone Java clients Go to next article: OSE and remote OSE