The Application Placement Controller is responsible for managing application servers in a dynamic cluster. For example, the Application Placement Controller can stop application servers when demand is low and start application servers in a dynamic cluster when demand is high.The Application Placement Controller will only be able to start/stop application servers in a dynamic cluster when the dynamic cluster is using Automatic mode. In other words, the Application Placement Controller will not start/stop application servers when the dyanmic cluster is in Manual mode or Supervised mode.

In the WebSphere admin console, navigate to Operational Policies > Autonomic Managers > Application Placement Controller to view and update the configuration of the Application Placement Controller. The screen shot below shows the default settings of the Application Placement Controller.

Approval Timeout

Approval timeout is the number of minutes to wait before a task in queue is rejected. Approval timeout can be anywhere from 1 to 60 minutes. When a dynamic cluster is in supervised mode, an alert will be created that the task should be rejected but the task will not actually be rejected. In automatic mode, the task will be rejected.

Server operation timeout

Server operation timeout is the number of minutes to wait before a request to start or stop a cluster member is considered a failure. Server operation timeout can be anywhere from 1 to 60 minutes.

Minimum time between placement change

Minimum time between placement change is the number of minutes to wait before initiating a new batch fo changes. Minimum time between placement change can be anywhere from 1 minute to 24 hours.