Part 4: Clone the application

Now you can make copies of the application to perform workload management and provide vertical and horizontal scaling. See "Using Models and Clones" for a discussion of these features in WebSphere Application Server Version 3.5.

In this case, you will clone the application server you configured, and all of its contents, so that all the resources can participate in the workload management.

  1. Create a model
  2. Create a clone

  Cloning creates many resources in your Topology tree. For usability and performance reasons, you might be required to click the Refresh button in order to view the newly added children of a model or clone in the Topology tree.

If you think that you are not seeing all of the resources under a model or clone (for example, your view does not agree with the screen captures in this section), click the parent clone or model whose children you are not seeing. Click the Refresh button located in the far left position on console tool bar.

Let's begin.

4.1: Create a model

First, locate the application server you configured in an earlier part of the tutorial, MyAppServer. You can find it in the Topology tree on the Topology view:

Right-click MyAppServer and click Create -> Model. The first step in cloning is to create a model of the application server. A model is an active template for creating clones. When you change the properties of a model, the change is automatically propagated to all of the clones.

A dialog box is displayed for specifying the model properties:

Specify a model name and select both check boxes. The first check box, making the original application server one of the clones, is optional. The second check box, Recursively Model all Instances under MyAppServer, is required if you are to create clones of not only the application server but the Account application it contains.

Note the dialog box contains one more opportunity to modify the properties of the original application server before making it a clone. Click OK to finish creating the application server model:

Back in the Topology tree, the first thing you might notice is that the icon of MyAppServer is enclosed in a yellow box, which signifies that it is now a clone. The contents of the application server are also represented as models (blue-green boxes) and clones (yellow boxes):

Scroll down in the Topology tree and you will find the MyAppServerModel you created. Each resource it contains is a counterpart of a resource in the original MyAppServer, which is now a clone of this model:

4.2: Create a clone

Right-click MyAppServerModel. Select to create a clone:

A properties dialog is displayed for specifying the clone properties:

Specify a name by which to administer the clone: MyAppServerClone. Specify that it will reside on your local machine (here, rufusdlion). Click Create:

This operation might require a few moments, depending on your system resources. When it is finished, a confirmation dialog will be displayed:

To see the clones that now exist for the model MyAppServerModel, click Application Server clones, underneath it in the Topology tree:

Some read-only information about the clones is displayed on the right side of the console. The state indicates the current state of the clones. Right now, both are stopped.

The desired state indicates the state the administrative server will try to put the clones into the next time it is started. Here, the desired state is read-only, but you can modify it in the properties of the model. Modifying the desired state setting of the model modifies the same setting of the clones.

To see the properties of an individual clone, click it in the Topology tree to display the properties on the right side of the console. For example, click MyAppServerClone:

Now start MyAppServerModel by right-clicking it and clicking Start on its pop-up menu. After this operation completes, you will see that MyAppServerClone and MyAppServer have both started, too:

Further steps are required to use workload management -- steps outside of the WebSphere Administrative Console. See Cloning for workload management, failover, and scaling for a summary of the steps required to enable clients (Java applications, servlets, and such) to exercise workload-managed enterprise beans.

One of the steps requires running a "wlmjar" command on the deployed enterprise bean JAR file. To continue with the Account sample, run wlmjar against the DeployedAccount.jar file in the deployedEJBs directory. Refer to the command line arguments and other considerations discussed in workload management for enterprise beans".

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