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Web server plug-in properties



Overview

The plug-in configuration file, plugin_cfg.xml, provides properties for establishing communication between the Web server and the appserver.

On the Configuration tab, we can edit fields. On the Runtime tab, we can look at read-only information.

The Runtime tab is available only when this Web server has accessed applications running on appservers and there is an http_plugin.log file.


Properties

Ignore DNS failures during Web server startup Whether the plug-in ignores DNS failures within a configuration when starting.

This field corresponds to the IgnoreDNSFailures element in plugin-cfg.xml.

When set to true, the plug-in ignores DNS failures within a configuration and starts successfully if at least one server in each ServerCluster is able to resolve the host name. Any server for which the host name can not be resolved is marked unavailable for the life of the configuration. No attempts to resolve the host name are made later on during the routing of requests. If a DNS failure occurs, a log message is written to the plug-in log file and the plug-in initialization continues rather than causing the Web server not to start. When false is specified, DNS failures cause the Web server not to start.

Data type String
Default false

Refresh configuration interval Time interval, in seconds, at which the plug-in should check the configuration file to see if updates or changes have occurred. The plug-in checks the file for any modifications that have occurred since the last time the plug-in configuration was loaded.

In a development environment in which changes are frequent, a lower setting than the default setting of 60 seconds is preferable. In production, a higher value than the default is preferable because updates to the configuration will not occur so often. If the plug-in reload fails for some reason, a message is written to the plug-in log file and the previous configuration is used until the plug-in configuration file successfully reloads. If not seeing the changes you made to the plug-in configuration, check the plug-in log file for indications of the problem.

Data type Integer
Default 60 seconds.

Plug-in configuration file name File name of the configuration file for the plug-in. The Application Server generates plugin-cfg.xml by default. The configuration file identifies applications, Application Servers, clusters, and HTTP ports for the Web server. The Web server uses the file to access deployed applications on various Application Servers.

We can change the name of the plug-in configuration file. However, if we do change the file name, also change the Web server configuration to point to the new plug-in configuration file.

If we select a Web server plug-in during installation, the installer program configures the Web server to identify the location of plugin-cfg.xml, if possible. The plug-in configuration file, by default, is installed in the PLUGINS_ROOT/config/web_server_name directory.

The installer program adds a directive to the Web server configuration that specifies the location of plugin-cfg.xml.

For remote Web servers, copy the file from the local directory where the appserver is installed to the remote machine. This is known as propagating the plug-in configuration file. If using IBM HTTP Server V6.1 or higher for the Web server, WAS can automatically propagate the plug-in configuration file for you to remote machines provided there is a working HTTP transport mechanism to propagate the file.

We can click View to display a copy of the current plug-in configuration file.

Data type String
Default plugin-cfg.xml

Automatically generate plug-in configuration file To automatically generate a plug-in configuration file to a remote Web server:

  • This field must be checked.
  • The plug-in configuration service must be enabled

When the plug-in configuration service is enabled, a plug-in configuration file is automatically generated for a Web server whenever:

  • The WAS administrator defines new Web server.
  • An application is deployed to an appserver.
  • An application is uninstalled.
  • A virtual host definition is updated and saved.

By default, this field is checked. Clear the check box to manually generate a plug-in configuration file for this Web server.

When the plug-in configuration file is generated, it does not include admin_host on the list of virtual hosts. The Information Center article "Allowing Web servers to access the admin console" describes how to add admin_host to the list of virtual hosts.

Automatically propagate plug-in configuration file Whether or not you want the appserver to automatically propagate a copy of a changed plug-in configuration file to a Web server:

  • This field must be checked.
  • The plug-in configuration service must be enabled
  • For WAS ND, a node agent must be on the node that hosts the Web server associated with the changed plug-in configuration file.

By default, this field is checked.

The plug-in configuration file can only be automatically propagated to a remote Web server if that Web server is an IHS v6.1 or higher, and its administration server is running.

Because the plug-in configuration service runs in the background, the admin console cannot show the results of the automatic propagation.

For distributed platforms, we can check the related messages in the dmgr SystemOut.log file to verify that the automatic propagation successfully completed.

Plug-in key store file name Fully qualified directory path and file name of the database file containing the security key rings that the Web server plug-in uses for HTTPS requests. This file resides on the Web server that is associated with this Web server plug-in. After specify the fully qualified directory path and file name of the database file, we can:

  • Cick Manage keys and certificates to update this file.
  • Click Copy to Web server key store directory to add a copy of this file to the key store directory for the Web server.

Data type String
Default None

Plug-in configuration directory and file name Fully qualified path of the Web server copy of the Web server plug-in configuration file. This path is the name of the file and its location on the machine where the Web server is running.
Plug-in key store directory and file name Fully qualified path of the Web server copy of the database file that contains the security key rings. This path is the name of the file and its location on the machine where the Web server is running.
Plug-in logging Location and name of the http_plugin.log file. Also specifies the scope of messages in the log.

The log describes the location and level of log messages that are written by the plug-in. If a log is not specified within the configuration file, then, in some cases, log messages are written to the Web server error log.

On a distributed platform, if the log file does not exist then it will be created. If the log file already exists, it will be opened in append mode and the previous plug-in log messages will remain.

Log file name - The fully qualified path to the log file to which the plug-in will write error messages.

Data type String
Default PLUGINS_ROOT/logs/web_server_name/http_plugin.log

Specify the file path of the http_plugin.log file.

Log level The level of detail of the log messages that the plug-in should write to the log. We can specify one of the following values for this attribute:

    Trace All of the steps in the request process are logged in detail.
    Stats The server selected for each request and other load balancing information relating to request handling is logged.
    Warn All warning and error messages resulting from abnormal request processing are logged.
    Error Only error messages resulting from abnormal request processing are logged.
    Debug All of the critical steps performed in processing requests are logged.
    Detail All of the information about requests and responses are logged.

If a Log level is not specified, the default value Error is used.

Be careful when setting the level to Trace. A lot of messages are logged at this level which can cause the disk space/file system to fill up very quickly. A Trace setting should never be used in a normally functioning environment as it adversely affects performance.

If the Web server and Web server plug-in are running on an AIX, HP-UX, Linux, or Solaris system, and you change the log level, in plugin-cfg.xml, this change is not picked up dynamically. You must restart the Web server to pick up the change. For example on Solaris, if we do not restart the Web server, the following error message appears in the Plugin_Home/logs/http_plugin.log file:

    ERROR: ws_config_parser:handleLogEnd: Failed to open log file '/IBM/WAS/Plugin/logs/sunwebserver/http_plugin.log', OS

Data type String
Default Error




Subtopics


Web server plug-in request and response optimization properties
Web server plug-in caching properties
Web server plug-in request routing properties

 

Related tasks


Communicating with Web servers