Apache Storm pluggable scheduler in Trident

Question

Core Storm allows to specify on what node a specific bolt should be executed by a means of pluggable scheduler. We are considering redesigning Storm topologies to Trident, but do not see how we can get the same behavior of configuring on what nodes some specific bolts should be executed using Trident topologies. Is scheduling still available with Trident? Thank you.

Answer 1

You can use the same way to specifying a custom scheduler using either low-level Java API or Trindent. From a scheduling perspective, there is no difference. See here for an example how to implement a custom scheduler: https://xumingming.sinaapp.com/885/twitter-storm-how-to-develop-a-pluggable-scheduler/

You can get some information about your Trident topology before submitting it as follows:

TridentTopology t = new TridentTopology();
// plug topology together

StormTopology st = t.build();
Map<String, SpoutSpec> spouts = st.get_spouts();
Map<String, Bolt> bolts = st.get_bolts();