Chapter 4. Writing Agent Plug-ins: Background

The agent's plug-in container. The plug-in contain runs inside the JBoss ON agent and it provides a manager for all of the deployed resource plug-ins.

The plug-in container is what actually manages the lifecycle of the resource plug-ins. The agent starts the plug-in container, and the plug-in container starts the resource plug-ins. The plug-in container also handles all the classloading, threading, and running for resource plug-ins.

Plug-in developers never need to interact with the plug-in container. As long as a plug-in is written with the appropriate components and with a valid plug-in descriptor, the agent will be able to manage the resource.

Domain objects. This defines the individual objects for plug-ins, specifically resources, resource types, and configuration. All of the other elements in AMPS use the domain objects to define resource elements.

One of the largest API sets within the domain object is configuration. The configuration API is used anywhere that a set of configuration properties is required, from plug-in configuration settings to connect to a resource to operation arguments.

The plug-in components. These components define the actual component interfaces that are used by agent plug-ins, well as the facets that plug-ins can support.

The plug-in components are the public API.

This element within AMPS is the part that plug-in writers use. This contains the interfaces that plug-in writers implement in the resource plug-in.

Native System. A lot of information require to monitor or manage a resource is available from the operating system information. The native system provides JNI or native access to that operating system information and can pull information from the process table, run external programs, or gather system metrics.

Resource plug-ins.. JBoss ON has a set of resource plug-ins already defined. Each individual resource plug-in manages a particular product (applications and servers, services, or platforms). These plug-ins are loaded into the agent's plug-in container and implement the plug-in components defined in the API.