With the following node yml configuration ThreadPool settings does not change :
threadpool:
type: scaling
scaling:
min: 1
max: 5
scheduled_size: 5

The thread pool type is still cached from : http://localhost:9200/_cluster/nodes

After digging the source code we found that : ThreadPoolModule.configure() is wrong :
Class<? extends Module> moduleClass = settings.getAsClass("transport.type", CachedThreadPoolModule.class, "org.elasticsearch.threadpool.", "ThreadPoolModule");

i guess it should be as : settings.getAsClass("threadpool.type"

Abdurrahim Eke
www.ifountain.com