Rebalancing executors in Apache Storm

Question

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 MyT

Answer 1

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

See here for details: https://storm.apache.org/documentation/Understanding-the-parallelism-of-a-Storm-topology.html