NonStop Servlets for JavaServer Pages (5.0) System Administrator's Guide

Programming and Management Features
NonStop Servlets for JavaServer Pages (NSJSP) System Administrator’s Guide—525644-002
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Overview and Architecture
When an admin operation is run in Tomcat (after the Save button is clicked), the
change takes effect immediately. For example, a change made to the Debug Level
property of the Server object directly affects the Tomcat server at the time the Save
button is clicked. Later, the Commit Changes command simply serializes the Tomcat
server configuration back to the server.xml file.
An NSJSP 5.0 container is a TS/MP ServerClass, which consists of multiple server
processes. A simple change made to the container requires NSJSP to propagate it to
every running server in the ServerClass as well as any subsequently started dynamic
servers. Thus, the NSJSP container can maintain a consistent service among its
server processes. To achieve this, a new ServerClass, named nsjspadmin is a front-
end to the administration and management functions. The SERVLET ServerClass
handles just the application requests.
The admin requests are first routed to the nsjspadmin ServerClass (by adding a new
Filemap to the iTP WebServer). Through the nsjspadmin server, the operator
browses objects and performs updates. When an update is made by selecting the
Save button, the save operations do not change the object properties in the SERVLET
ServerClass immediately. At this time, only the nsjspadmin server remembers the
saved changes. When the Commit Changes operation is processed, the nsjspadmin
server updates the iTP_server.xml configuration file and broadcasts all the saved
changes to all running server instances of the SERVLET ServerClass. Only at this time
are the object properties actually changed.
Note. If the nsjspadmin server fails for any reason (or the server is stopped), the servlet
ServerClass continues running. All web applications except admin and manager are still
accessible.