Bundled agents are Veritas Cluster Server (VCS) processes that manage resources of predefined resource types according to commands received from the VCS engine, HAD. You install these agents when you install VCS.
A node has one agent per resource type that monitors all resources of that type. For example, a single IP agent manages all IP resources.
When the agent starts, it obtains the necessary configuration information from VCS. The agent then periodically monitors the resources, and updates VCS with the resource status.
For a more detailed overview of how agents work, refer to the Veritas Cluster Server Administrator's Guide.