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Storm在集群上运行一个Topology时，主要通过以下3个实体来完成Topology的执行工作：
1. Worker（进程）
2. Executor（线程）
3. Task

下图简要描述了这3者之间的关系：

上图和下面这张图一样

看看官网的对这部分的讲解

Example of a running topology

The following illustration shows how a simple topology would look like in operation. The topology consists of three components: one spout called BlueSpout and two bolts called GreenBolt and YellowBolt. The components are linked such that BlueSpout sends its output to GreenBolt, which in turns sends its own output to YellowBolt.

The GreenBolt was configured as per the code snippet above whereas BlueSpout and YellowBolt only set the parallelism hint (number of executors). Here is the relevant code:

Config conf = new Config();conf.setNumWorkers(2); // use two worker processestopologyBuilder.setSpout("blue-spout", new BlueSpout(), 2); // set parallelism hint to 2topologyBuilder.setBolt("green-bolt", new GreenBolt(), 2)               .setNumTasks(4)               .shuffleGrouping("blue-spout");topologyBuilder.setBolt("yellow-bolt", new YellowBolt(), 6)               .shuffleGrouping("green-bolt");StormSubmitter.submitTopology(        "mytopology",        conf,        topologyBuilder.createTopology()    );