worker.yaml and worker.pid in workers.artifacts directory

[Mitchell Rathbun (BLOOMBERG/ 731 LEX)]

I have noticed that when I run a topology, all the worker related logs are 
written by default to 
"${sys:workers.artifacts}/${sys:storm.id}/${sys:worker.port}/${sys:logfile.name}",
 as specified by the default worker.xml file. I have noticed that if I update 
the filename used in the worker.xml file, all of the logs are sent to the 
specified directory. However, the original specified path will still be 
populated with just worker.pid and worker.yaml files. What are these files used 
for? Is it possible to update the log directory specified by worker.xml and 
then have the worker.pid and worker.yaml files written to that same directory?