Changing the domain configuration at runtime

The configuration, which has been created before starting the domain, can actually be changed without restarting the domain. One example of this could be if you need to create, on the fly, a new server group and associate some servers and applications to it.

This is not an academic example. As a matter of fact, it can happen that some of your applications in production have some issues that need to be fixed. You might as well reproduce the issue on a development environment, but that’s not always accurate, since development and production often use different database and class versions.

So, what might you do to quickly solve the issue? Create a new server group, for example, associate one or more servers to it, and deploy and test the application on it.

This can be done using the admin console (and also the CLI) in a matter of minutes. Bring back the admin console, and select the Profiles tab in the upper right area. From there choose the Groups Configuration in the left column of your GUI. This interface will let you Add server groups by clicking on the Add button:

Then, choose a meaningful name for your group, for example, Staging will be just fine, and select a Server Group configuration on which the new group will be based:

Good. Now, it’s time to associate one or more servers to the new group. Move to the Hosts section, and pickup any server from the Server Configuration menu, followed by the button Add.

This will actually bring you to a dialog box, which will ask you the new server name and the associated server group. For example, add the Test Server and associate it to the Staging group, with a port offset of 750 (in practice, every service will be bound to a port of default port address + 750).

Once you have set up a new server group and one or more servers that are part of it, you can use it to deploy your applications. Deployment of applications can be done from the Runtime upper tab, which will activate the Deployments panel, in the lower-left side of the screen:

From there, you can add and remove deployments to your groups. Complete details about application deployment are included in the next chapter, which is all about deploying applications on JBoss AS 7.

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