Map modules to servers

Each module of a deployed application must be mapped to one or more target servers. The target server can be an application server, cluster of application servers or web server.

We can map modules of an application or stand-alone Web module to one or more target servers during or after application installation using the console. This topic assumes that the module is already installed on a server and to change the mappings.

Before changing a mapping, check the deployment targets. Specify an appropriate deployment target for a module. Modules that use Version 8.x features cannot be installed onto Version 7.x or 6.x target servers. Similarly, modules that use Version 7.x features cannot be installed onto Version 6.x target servers.

During application installation, different deployment targets might have been specified.

Use the Manage modules page of the console to view and change mappings. This page is displayed during application installation using the console and, after the application is installed, can be accessed from the enterprise application settings page.

On the Manage modules page, specify target servers where to install the modules contained in the application. Modules can be installed on the same application server or dispersed among several application servers. Also, specify the web servers as targets that will serve as routers for requests to the application. The plug-in configuration file, plugin-cfg.xml, for each web server is generated based on the applications which are routed through it.

If an application is running, changing an application setting causes the application to restart. On stand-alone servers, the application restarts after you save the change. On multiple-server products, the application restarts after you save the change and files synchronize on the node where the application is installed. To control when synchronization occurs on multiple-server products, deselect Synchronize changes with nodes on the Console preferences page.

1. Click...
   Applications | Application Types | WebSphere enterprise applications | application_name | Manage modules

   The Manage modules panel is displayed.

2. Examine the list of mappings.

   Ensure that each Module entry is mapped to one or more targets, identified under Server.

3. Change a mapping as needed.

   1. Select each module we want mapped to the same targets.

      In the list of mappings, select check boxes for the modules.

   2. If the security configuration supports multiple domains, select the domain that has the desired clusters or servers, or keep the All domains default.

      Select a domain causes the Clusters and servers list to show only the deployment targets configured in the domain. We cannot deploy the modules in an application across deployment targets that belong to different security domains.

   3. From the Clusters and servers list, select one or more targets.

      Select only appropriate deployment targets for a module. We cannot install modules that use WebSphere Application Server Version 8.x features on a Version 7.x or 6.x target server.

      Use the Ctrl key to select multiple targets. For example, to have a web server serve the application, use the Ctrl key to select an application server or cluster and the Web server together to have the plugin-cfg.xml plug-in configuration file for that web server generated based on the applications that are routed through it.

   4. Click Apply.

4. Repeat steps 2 and 3 until each module maps to the desired targets.

5. Click OK.

Results

The application or module configurations are changed. The application or stand-alone web module is restarted so the changes take effect.

Example

To install an application that has modules which support Java EE 5 or 6 to two servers, do the following:

1. Click the Select All icon to select all of the modules in the application.

2. While pressing Ctrl, select two Version 8 application servers from the Clusters and servers list.

3. Click Apply.

4. Click OK.

What to do next

If the application or module is deployed on a cluster and the configuration changes are complete, click Rollout Update on the Enterprise applications page to propagate the changed configuration on all cluster members of the cluster on which the application or module is deployed. Rollout Update sequentially updates the configuration on the nodes containing cluster members.

Save changes to the administrative configuration.

The application binaries are transferred to nodes when the configuration changes on the deployment manager synchronize with configurations for individual nodes on which the application will run.

Avoid trouble: If, at a future time, you intend to delete the server or cluster to which the modules are mapped, add a new server or cluster and then remap the modules to it before deleting the previous server or cluster. If we do not remap the modules to a new server or cluster before deleting the previous one, you must uninstall each application or module and then reinstall them on an existing server or cluster. After a server or cluster to which modules are mapped is deleted, the modules cannot be remapped to another existing server or cluster.gotcha

Related concepts

Installable enterprise module versions

Multiple security domains

Configure enterprise application files

Install enterprise application files with the console

Manage modules settings

Enterprise application collection

Enterprise application settings