NonStop Servlets for JavaServer Pages (NSJSP) 6.0 System Administrator's Guide

Programming and Management Features
NonStop Servlets for JavaServer Pages (NSJSP) 6.0 System Administrator’s Guide—544548-004
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Overview and Architecture
Overview and Architecture
The NSJSP Admin operations do not behave the same way as the Apache Tomcat
implementation, which is a standalone application. When an Admin operation is run in
Tomcat (after clicking Save), the change takes effect immediately.
An NSJSP 6.0 container is a TS/MP ServerClass consisting of multiple server
processes. Any modification to the container requires NSJSP to propagate it to every
running server in the ServerClass in addition to any subsequently started dynamic
servers. Therefore, the NSJSP container can maintain a consistent service among its
server processes. To achieve this, a new ServerClass NSJSPADMIN, is a front-end to
the administration and management functions. The SERVLET ServerClass handles
only the application requests.
The Admin requests are first routed to the NSJSPADMIN ServerClass (by adding a new
Filemap to the iTP Secure WebServer). The operator browses objects and performs
updates through the NSJSPADMIN server. When you select Save to make an update,
the save operations do not change the object properties in the SERVLET ServerClass
immediately. The NSJSPADMIN server only remembers the saved changes. When the
Commit Changes operation is processed, the NSJSPADMIN server updates the
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.
Figure 4-1 shows that the operator commands received by the iTP Secure WebServer
are directed to the NSJSPADMIN server. Figure 4-2 shows that when you click Commit
Changes, the NSJSPADMIN server first updates the server.xml configuration file,
and broadcasts all the saved changes in a chunk to every running server instance of
the SERVLET ServerClass. As a result, the subsequently created servers have the
same configuration as the currently running servers.
Note. If the NSJSPADMIN server fails for any reason (or the server is stopped), the SERVLET
ServerClass continues to run. All web applications, except Admin and Manager, are still
accessible.
Figure 4-1. Operator Save Command
httpd
nsjspdmin
server
httpd
httpd
object browses,
updates, &
“SAVE”