java - Amount of executors in Storm -

i'm playing around storm. topology i'm using:

builder.setspout("word", new randomsentencespout(), 3); builder.setbolt("exclaim1", new exclamationbolt(), 6).shufflegrouping("word"); 

i thought storm spawn 9 executors (3 spouts + 6 bolts) topology, when run it, can see 11 executors running.

what 2 executors?

they acker bolts responsible managing acknowledgment mechanism. there 2 acker in topology , each bolt task 1 executor default.

storm uses acker bolt task (executor) , if don't set number of ackers, run of them in topology. if want manage number of executors, use following :

config conf = new config(); conf.setnumackers(1);