Entities are the fundamental units of observation/monitoring in the system.

Essentially, an entity is a process (pid). As processes, all entities are uniquely identifiable by their pids. Associated with each entity is a symbolic name that can be used to refer to that specific entity. Again, the names associated with entities are unique across the system. Managers are currently associated with a node, so uniqueness rules apply to a node. As we'll see later, this uniqueness requirement is very similar to the naming scheme used in a hierarchical filesystem.

There are three fundamental entity types: