1.6. About Managed Domains

A managed domain is one of two operating modes for a JBoss EAP instance. It is a mode to manage multiple instances of JBoss EAP from a single point of control.
A collection of servers that are centrally managed are known as members of a domain. All the JBoss EAP instances in the domain share a common management policy. A domain consists of one domain controller, one or more host controller(s), and zero or more server groups per host.
A domain controller is the central point from which the domain is controlled. It ensures that each server is configured according to the management policy of the domain. The domain controller is also a host controller. A host controller is a physical or a virtual host on which the domain.sh or domain.bat script is run. Unlike the domain controller, the host controllers are configured to delegate domain management tasks to it. The host controller on each host interacts with the domain controller to control the lifecycle of the application server instances running on its host and to assist the domain controller to manage them. Each host can contain multiple server groups. A server group is a set of server instances, which has JBoss EAP installed on it and are managed and configured as one. Since the domain controller manages the configuration and applications deployed onto server groups, each server in a server group shares the same configuration and deployments.
It is possible for a domain controller, a single host controller, and multiple servers to run within the same instance of the JBoss EAP, on the same physical system. Host controllers are tied to specific physical (or virtual) hosts. You can run multiple host controllers on the same hardware if you use different configurations, so that the ports and other resources do not conflict.
A managed domain with one domain controller, three host controllers, and three server groups. Servers are members of server groups, and may be located on any of the host controllers in the domain.

Figure 1.1. Graphical Representation of a Managed Domain