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Implement a web server plug-in

WebSphere Application Server works with a web server to route requests for dynamic content, such as servlets, from web applications. The web servers are necessary for directing traffic from browsers to the applications that run on an application server. The web server plug-in uses the XML configuration file to determine whether a request is for an application server.

If the installation uses a firewall, configure the web server plug-in to use an open port.

(iSeries) The appropriate plug-in file is installed. In addition, an http profile is created...

The http profile can be used to facilitate the creation of web server definitions.

Use application-centric plug-in configuration. Global plugin configuration files are deprecated. An application-centric plugin-cfg.xml configuration file has an application that is mapped to both web server and application server definitions.


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.

  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 we configure a plug-in, the configuration file for that plug-in is automatically created. We can change or tune the default settings for the properties in this configuration file. If we change any of the settings, we must regenerate the file before our changes take effect.

Generating 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.


Enable/disable web server plug-in configuration service

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

...and clear the option...


Update the plug-in configuration file, including SSL and web server tuning

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

    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 the plugin-cfg.xml file.

    Regenerate the plugin-cfg.xml file using the administrative console:

      Servers > Server Types > Web Servers > web_server > plug-in properties > Automatically generate plug-in configuration file

    Do not manually update the plugin-cfg.xml file. Any manual updates we make for a web server are overridden whenever the plugin-cfg.xml file for that web server is regenerated.

    Click OK.

    We 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. 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:

    If neither of these conditions are true, we must manually copy the plugin-cfg.xml file to the location of the remote web server installation. Copy the plugin-cfg.xml file in...

      <app_server_root>/profiles/<profilename>/config/cells/../../nodes/../servers/<webservername>

    ...to the web server host location...

    If we 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 we need to manually copy the plugin-cfg.xml from an AIX operating system, we 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 we specified when we created the node for this web server.

    (iSeries) Propagate the plug-in configuration. To propagate the plug-in configuration from the administrative console, click...

      Servers > Server Types > Web serversweb_serverPropagate plug-in

    Another method to propagate the plug-in configuration is to run the GenPluginCfg command.

    We do not need to propagate the plug-in configuration if the web server is on the same machine as the associated stand-alone version of the product. If the propagation of the plug-in configuration fails due to an unknown cause, we must manually copy the plugin-cfg.xml file to the location for the remote web server installation.

    If we use the FTP function to perform the copy, and the configuration reload fails, check the file authorities on the plugin-cfg.xml file and make sure that users QTMHHTTP, QNOTES and QEJBSVR have RWX authority. If the authorities are not correct, the web server cannot access the new version of the file, which causes the configuration reload to fail. To check the authorities, run the following IBM i command:

      wrklnk 'plug_in_folder_location/plugin-cfg.xml'

    Then select option 9 to view the authorities assigned to the users (QTMHHTTP, QNOTES, and QEJBSVR). If the authorities are incorrect, issue the following IBM i command to change the file authorities to the appropriate settings:

      CHGAUT USER(QEJBSVR QTMHHTTP QNOTES) OBJ('plug_in_folder_location/plugin-cfg.xml') DTAAUT(*RWX)

    The plug_in_folder_location is the location we specified when you transferred the plugin-cfg.xml file.

  3. Copy the keystore file to the keystore directory on the web server.

    This step is required for the web server to function properly.

    For detailed instructions on copying the keystore file, read the topic on configuring the web server plug-in for Secure Sockets Layer.

  4. Tune the web server.

The configuration is complete. To activate the configuration, stop and restart the web server. If we encounter problems restarting the web server, check the http_plugin.log file for information about what portion of the plugin-cfg.xml file contains an error. The log file states the line number on which the error occurred, along with other details that might help you diagnose why the web server did not start. We can then use the administrative console to update the plugin-cfg.xml file.

If applications are infrequently installed or uninstalled, which is usually the situation in a production environment, or if we can tolerate the performance impact of generating and distributing the plug-in configuration file each time any of the previously listed actions occur, consider enabling the configuration service.


Subtopics


Related:

  • Select a front end for our WAS topology
  • Transport chains
  • Configure the web server plug-in for Secure Sockets Layer
  • Key store settings
  • Configure transport chains
  • Change the HTTP plug-in configuration
  • Tune web servers
  • Add, manage, and remove nodes
  • (iSeries) Stopping an application server
  • (iSeries) Starting an application server
  • Install the application serving environment
  • (ZOS) z/OS - Installing IBM HTTP Server
  • GenPluginCfg command