> a "topology" in Storm is a directed acyclical graph. The nodes are called "bolts" and the edges are called spouts" Not really. Edges are streams and nodes ar

> a "topology" in Storm is a directed acyclical graph. The nodes are called "bolts" and the edges are called spouts" Not really. Edges are streams and nodes are either spouts or bolts. Spouts have no predecessors and inject external data into the system. Bolts gather one or more input streams and produce zero or more output streams. These names are a bit confusing, but only during the very first steps of a project. Quickly every developers grasp the concepts. I have nevertheless a concern regarding spouts and bolts. In practice, when a topology is refactored, bolts have frequently to be transformed into spouts. This occurs when a topology is split in two to ease deployment; and when a persistent queue is added along a stream. This highlights that the distinction between spouts and bolts is bit artificial.