在 Apache Storm 中重新平衡执行器 [英] Rebalancing executors in Apache Storm

问题描述

我正在尝试重新平衡正在运行的 Apache Storm (0.9.5) 拓扑中螺栓的执行程序数量.当我对 Nimbus 节点 ./storm rebalance MyTopology -n 2 -e GreenBolt=4 执行命令时，它接受命令行输入，但当我在 Storm UI 中查看时，执行程序的数量没有改变.

I am trying to rebalance the number of executors for a bolt in a running Apache Storm (0.9.5) topology. When I execute the command to the Nimbus node ./storm rebalance MyTopology -n 2 -e GreenBolt=4 it accepts the command line input but the number of executors is not changed when I view in the Storm UI.

是否有我不知道的限制，例如重新平衡不能增加执行程序的总数，而只能将它们从一个螺栓移动到另一个螺栓?

Is there a limitation that I'm not aware of like a rebalance can not increase the total number of executors and only move them from one bolt to another?

推荐答案

您总是需要比执行者拥有更多(或相等数量)的任务.由于任务数量是固定的，因此您需要设置比初始执行程序更大的初始数量，以便能够在运行时扩展执行程序的数量.您可以看到任务数，作为最大执行者数:

You always need to have more (or equal number of) tasks than executors. As the number of tasks is fixed, you need to set a larger initial number than initial executors in order to be able to scale up the number of executors during runtime. You can see the number of tasks, as maximum number of executors:

#executors <= #numTasks

请参阅此处了解详情:https://storm.apache.org/documentation/Understanding-the-parallelism-of-a-Storm-topology.html

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