I am running Dask Distributed on Linux CentOS 7, with a Python 3.6.2 installation. My computation seems to be getting fine (I am still improving my code, but I am able to have some results), but I keep getting some python errors apparently linked to tornado module. I am only launching a one node standalone Dask distributed cluster.
Here is the most common example:
Exception in thread Client loop:
Traceback (most recent call last):
File "/usr/local/lib/python3.6/threading.py", line 916, in _bootstrap_inner
self.run()
File "/usr/local/lib/python3.6/threading.py", line 864, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.6/site-packages/tornado/ioloop.py", line 832, in start
self._run_callback(self._callbacks.popleft())
AttributeError: 'NoneType' object has no attribute 'popleft'
And here is another one:
tornado.application - ERROR - Exception in callback <bound method WorkStealing.balance of <distributed.stealing.WorkStealing object at 0x7f752ce6d6a0>>
Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/tornado/ioloop.py", line 1026, in _run
return self.callback()
File "/usr/local/lib/python3.6/site-packages/distributed/stealing.py", line 248, in balance
sat = s.rprocessing[key]
KeyError: 'read-block-9024000000-e3fefd2110094168cc0505db69b326e0'
Do you have any idea why? Should I close some connections or stop the standalone cluster?
Yes, if you don't close down the Tornado IOLoop before exiting the process then it can die in an unpleasant way. Fortunately this shouldn't affect your application, except by looking unpleasant.
You might submit a bug report about this, it's still something that we should fix.