Did you know you can access the WebSphere Application Server from multiple HTTP servers running on the same or different iSeries machines?
That's something you may want to consider if you want to isolate the compute-intensive resources of WebSphere Application Server or if you want to isolate WebSphere resources from user access for security reasons.
All access to your system is via the HTTP server. It is the HTTP server that communicates with the user and with WebSphere. It can provide a crude form of firewall-type separation (by no means a real firewall).
You can position either product where it makes the most sense for resource allocation. In some cases you may wish to put both on the same machine and access your database on a second machine. In some cases you may want three separate machines, with HTTP Server on one, WebSphere on another, and your database and legacy applications (i.e. RPG programs) on yet another. Two machines is a common approach. It makes good sense to position WebSphere close to your applications on the same box as your database and applications while keeping your HTTP server isolated on a separate machine.
You can mix, match, or run everything on one machine, whatever makes the most sense to you. On the iSeries, this is relatively easy (compared with other platforms).
How to do it
Follow these steps to install the WebSphere Application Server (Standard Edition, Single Server Edition or Advanced Edition) on one of your iSeries machines and run HTTP servers on different machines that need access to your WebSphere Application Server.
You must first install the WebSphere base on your HTTP server machine. For V5R1, this is 5733-WA3 Option 0 (zero). This installs the communication and plug-in code and does not install a fully functional WebSphere Application Server. (The full server is installed via Option 1.)
You must then create a subdirectory in /QIBM/UserData/WebASAdv4/mydir with any name you choose.
In Qshell (QSH) you must run the
/QIBM/ProdData/WebASAdv4/bin/crtreminst ?instance mydir
command to create the necessary subdirectories and resources on this machine.
You must now look on the machine where the WebSphere Application Server is installed and copy the plugin-cfg.xml file to your remote HTTP server machine.
Copy:
/QIBM/UserData/WebASAdv4/Default/config/plugin-cfg.xml fl On your WebSphere machine.
To:
/QIBM/UserData/WebASAdv4/mydir/config/plugin-cfg.xml fl On your HTTP server machine.
When you configure the HTTP Server using the original or Apache-based HTTP server, you will now see three choices for "WebSphere Domain" on the Java Servlet admin page. In addition to Default and Service, you will see "mydir" (the name you gave to the directory).
Be sure to check out the documentation available on IBM's Web site. Once there, select documentation and pick the release applicable to your system (3.5 Standard, 4.0 Advanced Edition, or 4.0 Single Server. Instructions will vary slightly between releases. These instructions work for V4.x Advanced Edition of WebSphere.
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About the author: Bob Cancilla is managing director of IGNITe/400, an electronic iSeries 400 Internet users group. He is also author of the book Getting Down to e-business with AS/400.
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