动态改变storm的并发度

How to change the parallelism of a running topology, 动态的改变并发度

Storm支持在不restart topology的情况下, 动态的改变(增减)worker processes的数目和executors的数目, 称为rebalancing. 

通过Storm web UI, 或者通过storm rebalance命令, 见下面的例子

A nifty feature of Storm is that you can increase or decrease the number of worker processes and/or executors without being required to restart the cluster or the topology. The act of doing so is called rebalancing.

You have two options to rebalance a topology:
Use the Storm web UI to rebalance the topology.（怎么使用？）
Use the CLI tool storm rebalance as described below.

Here is an example of using the CLI tool:

# Reconfigure the topology "mytopology" to use 5 worker processes,
# the spout "blue-spout" to use 3 executors and
# the bolt "yellow-bolt" to use 10 executors.

$ storm rebalance mytopology -n 5 -e blue-spout=3 -e yellow-bolt=10