Storm Execution Flow

http://stackoverflow.com/questions/28981197/execution-flow-of-a-storm-program

http://storm.apache.org/releases/1.0.1/Tutorial.html

First, when your topology is started...

1. Create Spouts and Bolts

2. declareOutputFields

3. Spouts/Bolts serialized and assigned to workers

Second, in each worker somewhere on the cluster...

1. Spouts open and Bolts prepare (happens once)

2. In a loop...

• Spouts call ack, fail, and nextTuple

• Bolts call execute

If your topology is deactivated...

• Your spouts deactivate method will be called. When you activate the topology again then activate will be called.

If your topology is killed...

• Spouts might have close called

• Bolts might have cleanup called

Note:

There is no guarentee that close will be called, because the supervisor kill -9's worker processes on the cluster. source