Hi when using the process module we are unable to get the metrics for system.processes.open_file_descriptors. I have dug around the python code a bit and found that the following errors are emitted... ( note that i changed the log method to info so i could see the errors ).

2015-11-02 22:36:48 UTC | INFO | dd.collector | checks.process(process.py:161) | psutil was denied acccess for method num_fds
2015-11-02 22:36:48 UTC | INFO | dd.collector | checks.process(process.py:161) | psutil was denied acccess for method io_counters

Im guessing that the psutil module does not have access to something in /proc.