A user of the ION Grid should be aware of the following concepts when installing and administering the grid.
A node type defines what to run in a specific node. Each node is of exactly one node type. More precisely, the node type defines what application to run in nodes of this type and may also define default values for properties (for example, heap size). Node types are defined by the application developer.
A binding defines where and how to run nodes of a specific node type. It can be seen as an association between a node type and a set of hosts. In order to start a specific node type on a particular host, a binding that associates the node type with the host is needed. Properties needed by the node or the application running in the node may be defined per binding.
Bindings are defined when applications are installed and/or by a grid administrator at runtime.
A grid application is a logical grouping of one or more application modules. An application may be running in more than one node. It is then said to have more than one application instance. Applications for the grid are packaged in gar files. A gar file is a type of zip file that can be installed in a grid. It contains Java class files (jar files) and any other resources that the application may need.