This topic describes how to implement a web server plug-in.
The product 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.
Before you begin
- See the information about choosing a front end for your WebSphere® Application Server topology. This topic helps you determine whether to
set up a web server plug-in, a proxy server, or a secure proxy server to provide session affinity,
failover support, and workload balancing for your WebSphere Application Server topology. Install your web server if it is not already installed.
Avoid trouble: The web server that is provided with
IBM® i, is already installed under product 5761-DG1 for
IBM i V6R1 or 5770-DG1 for
IBM i V7R1. The
IBM i web server is referred to as the IBM HTTP Server for
IBM i. This web server is different from the IBM HTTP Server that is provided with
WebSphere Application Server, which does not run on
IBM i.
gotcha
If you want
to use the IBM HTTP Server that is provided with the product,
see the information about installing IBM HTTP Server.
Otherwise, see the installation information that is provided with your web server.
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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 using the IBM HTTP Server for z/OS®, powered by Apache, which is provided with
the product, see the information about installing and configuring
the plug-in for IBM HTTP Server
for WebSphere Application Server on z/OS.
If you
are using the IBM HTTP Server Version 5.3, which is provided with
the z/OS base operating system,
see the information about installing and configuring the web server
plug-in for IBM HTTP Server for z/OS V5.3.
If you are using a distributed platform web server
with a version of the product that is running on z/OS operating systems, use an FTP connection
to send the plug-in to the web server and use the Plug-in Installation
Wizard to install the appropriate plug-in file to your web server.
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.
Avoid trouble: If your installation uses a firewall,
make sure that you configure the web server plug-in to use a port
that has been opened. See your security administrator for information
about how to obtain an open port.
gotcha
About this task
The appropriate plug-in file is installed.
In addition, an http profile is created (/QIBM/UserData/WebSphere/Plugins/V85/webserver/profiles/http).
The http profile can be used to facilitate the
creation of web server definitions. See the topic about selecting
a web server topology diagram and road map for instructions on how
to configure IBM HTTP Server
for IBM i to communicate with
an application server.
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![[z/OS]](../images/ngzos.gif)
The following steps are performed during the plug-in
installation process. See the Plug-in Installation Roadmap for additional
information.
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.
- A web server definition is created.
You can also use either
the administrative console or use the ConfigurewebServerDefinition.jacl script
to create a web server definition.
- An application or modules are mapped to a web server. If an application that you want 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.
- The master repository is updated and saved.
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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, you must regenerate
the file before your changes take effect.
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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.
The following procedure describes
the steps for updating the plug-in configuration file, including configuring
for SSL and web server tuning.
Procedure
- Use the administrative console to change the settings in
the plug-in configuration file.
When setting up your
web server plug-in, you must 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
Avoid trouble: 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.
gotcha
You 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
by using the administrative console:
- Select .
- Select Automatically generate plug-in configuration file, or click one
or more of the following topics to manually configure the plugin-cfg.xml
file:
Avoid trouble: 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.
gotcha
- Click OK.
Propagate the plug-in configuration. To propagate the plug-in configuration from the administrative console, click web_server_name. Another method to propagate the plug-in configuration is to run the
GenPluginCfg command. For more information, see the
GenPluginCfg command documentation.
You 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, you
must manually copy the plugin-cfg.xml file to the location for the remote web
server installation.
Avoid trouble: If you 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 that are assigned to the users (QTMHHTTP, QNOTES, and
QEJBSVR).
gotcha
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 you specified when you transferred the
plugin-cfg.xml file.
- 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.
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Tune your web server. See the page about tuning web servers for more information.
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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 Version 7 that has a running IBM HTTP
Server administration server.
If neither of these conditions are true, you 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, which is <PluginInstallRoot>/config/<webservername>/.
Important: 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
The AIX® FTP function
does not preserve file attributes. Therefore, if you need to 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.
- Copy the keystore file to the keystore directory on your
web server.
Avoid trouble: This step is required
for the web server to function properly.
gotcha
For detailed instructions
on copying the keystore file, read the topic on configuring the web
server plug-in for Secure Sockets Layer.
Results
The configuration is complete. To activate the configuration,
stop and restart the web server. If you encounter problems restarting
your 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. You 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 you 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.