Controlling dynamic updates

Three types of dynamic update can be controlled through configuration: changing the server configuration; adding and removing applications; updating installed applications. For all deployed applications, you can configure whether application monitoring is enabled and how often to check for updates to applications. For the "dropins" directory, you can also configure the name and location of the directory and choose whether to deploy the applications that are in the directory.

About this task

By default, deployed applications are monitored for updates, and the updates are dynamically applied to the running application. This applies both to applications that are deployed through configuration entries, and those deployed from the "dropins" directory. You can change these default behaviors by setting the config and applicationMonitor elements in the server.xml configuration file. You can use a text editor to do this, or you can use the developer tools and select Configuration Admin Service or Application Monitor in the server configuration design view.

See also the descriptions of the config and applicationMonitor elements in Enterprise JavaBeans Lite 3.1, Liberty Kernel, Java Servlets 3.0, and OSGi Blueprint.

The default settings for application monitoring are as follows:
<applicationMonitor updateTrigger="polled" pollingRate="500ms" 
                    dropins="dropins" dropinsEnabled="true"/>
The default settings for configuration monitoring are as follows:
<config updateTrigger="polled" monitorInterval="500ms"/>
Notes:
  • The updateTrigger property has three possible values:
    polled
    The runtime environment scans the server.xml file for changes by using the timing interval that is specified by the monitorInterval property.
    mbean
    The runtime environment looks for updates only when prompted to do so through a call to an MBean. This is the mode that is used by the developer tools to update the server.xml file, unless you override it.
    disabled
    The updates are not dynamically applied.
  • When you specify the pollingRate property or the monitorInterval property, you include the unit of time after the number:
    • ms (milliseconds)
    • s (seconds)
    • m (minutes)
    • h (hours)
  • The dropins property specifies the name of the directory that is used as the "dropins" directory.
  • The dropinsEnabled property is a boolean property that determines whether the applications in the "dropins" directory are deployed.

Procedure


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