One of the primary new features of WildFly is the ability to manage multiple WildFly instances from a single control point. A collection of such servers is referred to as the members of a "domain" with a single Domain Controller process acting as the central management control point.
All of the WildFly instances in the domain share a common management policy, with the Domain Controller acting to ensure that each server is configured according to that policy. Domains can span multiple physical (or virtual) machines, with all WildFly instances on a given host under the control of a special Host Controller process.
One Host Controller instance is configured to act as the central Domain Controller. 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 in managing them.
Configure network interfaces, JVM settings, and other properties for this host. Manage server instances for this host.