WildFly, formerly known as JBoss Application Server is an open-source application server. It follows the Java EE standard and is compatible with a variety of Java frameworks and libraries. It provides a runtime environment for deploying Java applications, including web applications, enterprise applications, and microservices.
WildFly can be booted in two different modes. A managed domain allows you to run and manage a multi-server topology. Alternatively, you can run a standalone server instance.
a.) Standalone Server:
A standalone server instance is an independent process. Standalone instances can be launched via the
standalone.bat launch scripts.
b.) Managed Domain:
One of the primary 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.
When you launch a WildFly managed domain on a host (via the
domain.bat launch scripts) your intent is to launch a Host Controller and usually at least one WildFly instance. On one of the hosts the Host Controller should be configured to act as the Domain Controller.