6.7. Managing the Agent as a Resource

The agent can be added as a resource to the JBoss ON inventory, so its behavior and metrics can be monitored to ensure that it is working properly and it can have alerts and operations launched, as with any other resource.

Important

If the agent is shut down, the JBoss ON GUI cannot be used to restart it because there is no active agent available to issue the start command. To restart the agent, use the restart operation on the agent's child resource of the launcher script, rather than the agent resource itself.
The shutdown operation kills the agent process if it is running as a daemon. If the agent is running as a command prompt, the shutdown operation stops the agent but not the JVM, so that prompt commands can still be run through the agent command prompt.
When the agent is imported into the inventory, several child resources are automatically added as well. These are listed in Table 16, “Agent Child Resources”.

Table 16. Agent Child Resources

Child Resource Description
The agent itself Provides monitoring, configuration, and control functionality for the agent and its internal components. These configuration settings correspond to the preferences defined in the agent-configuration.xml file and are persisted on the agent machine as Java preferences.

Important

The operations for the agent resource normally do not affect the agent process directory. These do not provide control over the JVM settings or process or the JRE options. Controlling the JVM is done through the agent child resources, not the agent resource.
Agent measurement subsystem Provides data on the measurement collection and reporting components in the agent.
Agent JVM Provides fine-grained monitoring and management of the JVM that is running the agent and all its plugins, which includes the classloader, threading and memory management subsystems, among others. This is a child server.
Agent environment setup script Configured environment variables that server set when the agent launcher script is started.
Agent plug-in container Provides a view into the embedded plug-in container and gives management data related directly to the plug-in container. The plug-in container runs within the agent and handles the deployment of all management plug-ins and infrastructure necessary to run those plug-ins.
Java service wrapper launcher (Windows) Controls the Java service wrapper. This is a third-party library that installs and runs the agent as a Windows service. There is one primary configuration file for the Java service wrapper, the read-only rhq-agent-wrapper.conf file. This defines the base set of configuration settings necessary for the agent to start and operate properly. Two additional groups of configuration settings can customize the agent's environment. The Environment group defines environment variables that are used by the main configuration in addition to the environment variables defined by the common Environment Setup Script. The Includes group defines any of the wrapper configuration settings. These groups should almost never be edited except to configure debugging or to pass new JVM options to the agent JVM.
Agent launcher script (UNIX) Controls the agent. If the agent is running as a background daemon process that was spawned by the launcher script, the launcher script stops or restarts it. There is no additional configuration. The launcher script is configured by the Environment Setup Script.