A JOnAS management domain is composed of a set of JOnAS servers that are running under the same management authority and are identified by a domain name.
The servers in a domain can be administered by a management application running on one server (or several) in the domain; this is the role of administrator or master. The managed servers play the role of slaves.
Typically when deploying the JonasAdmin application on a slave, the administrator can manage only the server on which the application is running. When deploying JonasAdmin on a master server, the administrator can manage all the servers in the domain.