Network Deployment (Distributed operating systems), v8.0 > Set up intermediary services


Implement a web server plug-in


Overview

Web servers serve static content. For dynamic content, such as servlets and portlets, the Web server can use plug-in files to route requests to WAS v8 application servers.

For the front end to the WAS topology you can set up either...

Front ends provide session affinity, failover support, and workload balancing.

WAS v8 is bundled with IBM HTTP Server.

Verify the web server is configured to run the operations that are required by web applications, such as GET and POST. Typically, configuring your web server to run these operations involves setting a directive in the web server configuration file (httpd.conf). If an operation is not enabled when a servlet or JSP file requiring the operation is accessed, an error message is displayed, such as this one from the IBM HTTP Server:

Make sure the appropriate plug-in file has been installed on your web server and the configureweb_server_name script has been run to create and configure the web server definition for this web server.

If you are using a distributed platform web server, use the web Server Plug-ins Configuration Tool to install the appropriate plug-in file to your web server. Then, run the configureweb_server_name script created by the tool to create and configure the web server definition in the WebSphere configuration repository.

If you are making a series of simultaneous changes, such as installing numerous applications, you might want the configuration service disabled until after you make the last change. The web server plug-in configuration service is enabled by default. To disable this service, in the administrative console click...

...and then clear the option...

If your installation uses a firewall, make sure that you configure the web server plug-in to use a port that has been opened.

The following steps are performed during the plug-in installation process.

  1. A node is created.

    An unmanaged node is created when the web server is on a different computer from the application server. An unmanaged node is a node that does not have a node agent running on it. Using unmanaged nodes, the product can represent servers that are not application servers within its configuration topology. This representation enables connection information between those servers and application servers to be maintained. See the topic about adding, managing, and removing nodes for more information.

  2. A web server definition is created.

    We can also use either the administrative console or use the ConfigurewebServerDefinition.jacl script to create a web server definition.

  3. An application or modules are mapped to a web server. If an application to use with this web server is already installed, the application is automatically mapped to the web server. If the application is not installed, select this web server during the "Map modules to servers" step of the application installation process.

  4. The master repository is updated and saved.

When you configure a plug-in, the configuration file for that plug-in is automatically created. You can change or tune the default settings for the properties in this configuration file. If you change any of the settings, regenerate the file before your changes take effect.

Generate or regenerating the configuration file might take a while to complete. After it finishes, all objects in the administrative cell use their newest settings, which the web server can access. If the application server is on the same physical workstation as the web server, the regeneration usually takes about 30 to 60 seconds to complete. The regeneration takes longer if the application server and web server are on different workstations.


Update the plug-in configuration file

  1. Use the administrative console to change the settings in the plug-in configuration file.

    When setting up your web server plug-in, decide whether to have the configuration automatically generated in response to a configuration change. When the web server plug-in configuration service is enabled and any of the following conditions occur, the plug-in configuration file is automatically generated:

    • When the web server is created or saved

    • When an application is installed

    • When an application is uninstalled

    • When the virtual host definition is updated

    When the plug-in configuration file is first generated, it does not include admin_host on the list of virtual hosts. The information about allowing web servers to access the administrative console describes how to add it to the list.

    We can either use the administrative console, or issue the GenPluginCfg command to regenerate your plugin-cfg.xml file.

    Complete the following steps to regenerate your plugin-cfg.xml file:

    1. Select Servers > Server Types > web Servers > web_server_name > plug-in properties.

    2. Select Automatically generate plug-in configuration file, or click one or more of the following topics to manually configure the plugin-cfg.xml file:

      We must delete the plugin-cfg.xml file in the $PROFILE_ROOT/config/cells directory before you complete this task. Otherwise, configuration changes do not persist to the plugin-cfg.xml file.

      • Cache
      • Request and response
      • Request routing
      • Custom Properties

      See the topic about web server plug-in configuration properties for information about how to map each property to one of these topics. Do not manually update the plugin-cfg.xml file. Any manual updates you make for a web server are overridden whenever the plugin-cfg.xml file for that web server is regenerated.

    3. Click OK.

    4. You might have to stop the application server and then start the application server for the web server to locate the plugin-cfg.xml file.

  2. Install the appropriate GSKIT installation image file on your workstation, to use Secure Sockets Layer (SSL) with this configuration.

  3. Tune your web server. See the page about tuning web servers for more information.

  4. Propagate the plug-in configuration. The plug-in configuration file, plugin-cfg.xml, is automatically propagated to the web server if the web server plug-in configuration service is enabled, and one of the following conditions is true:

    • The web server is a local web server, which means that the web server is located on the same workstation as an application server.
    • The web server is a remote IBM HTTP Server v7 that has a running IBM HTTP Server administration server.

    If neither of these conditions are true, manually copy the plugin-cfg.xml file to the location of the remote web server installation. Copy the plugin-cfg.xml file in WAS_HOME/profiles/ <profilename>/config/cells/../../nodes/../servers/ <webservername> to the web server host location, which is <PluginInstallRoot>/config/ <webservername>/.

    If you use the FTP function to copy the file, and the configuration reload fails, check the file permissions on the plugin-cfg.xml file, and make sure that they are set to rw-r--r--. If the file permissions are not correct, the web server is not able to access the new version of the file, which causes the configuration reload to fail.

    If the file permissions are incorrect, issue the following command to change the file permissions to the appropriate settings: 

    chmod 644 plugin-cfg.xml

    (AIX) The AIX FTP function does not preserve file attributes. Therefore, if manually copy the plugin-cfg.xml from an AIX operating system, you might want to use the AIX RCP function instead of the FTP function to copy the file.

    The remote web server installation location is the location you specified when you created the node for this web server.

  5. To activate the configuration, stop and restart the web server.

  6. Optional: Enable the configuration service


Related


Install IBM HTTP Server
Install and uninstall the Web Server Plug-ins
Edit web server configuration files
Allow web servers to access the administrative console
Web server plug-in properties
Application Server property settings for a web server plug-in
Web server plug-in configuration properties
Web server plug-in connections
Web server plug-in remote user information processing
Web server plug-ins
Check your IBM HTTP Server version
Create or updating a global web server plug-in configuration file
Gskit install images files
Plug-ins: Resources for learning
Web server plug-in tuning tips
Private headers
plugin-cfg.xml file
Set up a local web server
Set up a remote web server
Web server definition
Edit the web server type
Web server collection
Select a front end for your WAS topology
Transport chains
Configure the web server plug-in for SSL
Key store settings
Configure transport chains
Change the HTTP plug-in configuration
Tune web servers
Manage nodes
GenPluginCfg command

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