Remove old files and remove old documentation for copying files aroun…

…d cluster. (ray-project#274)

doc/using-ray-on-a-cluster.md

@@ -96,67 +96,3 @@ If the web UI doesn't work, it's possible that the web UI processes were never
 started (check `ps aux | grep polymer` and `ps aux | grep ray_ui.py`). If they
 were started, see if you can fetch the web UI from within the head node (try
 `wget http://localhost:8080` on the head node).
-
-### Copying Application Files to Other Nodes (Experimental)
-
-If you're running an application that imports Python files that are present
-locally but not on the other machines in the cluster, you may first want to copy
-those files to the other machines. One way to do that is through Ray (this is
-experimental). Suppose you're directory structure looks
-
-```
-application_files/
-    __init__.py
-    example.py
-```
-
-And suppose `example.py` defines the following functions.
-
-```python
-import ray
-
-def example_helper(x):
-  return x
-
-@ray.remote
-def example_function(x):
-  return example_helper(x)
-```
-
-If you simply run
-
-```python
-from application_files import example
-```
-
-An error message will be printed like the following. This indicates that one of
-the workers was unable to register the remote function.
-
-```
-Traceback (most recent call last):
-  File "/home/ubuntu/ray/lib/python/ray/worker.py", line 813, in fetch_and_register_remote_function
-    function = pickling.loads(serialized_function)
-ImportError: No module named 'application_files'
-```
-
-To make this work, you need to copy your application files to all of the nodes.
-The following command will do that through Ray, and will add the files to Python
-path of each worker. This functionality is experimental. You may be able to do
-something like the following.
-
-```python
-import ray
-
-ray.init(redis_address="<redis-address>")
-
-ray.experimental.copy_directory("application_files/")
-
-# Now the import should work.
-from application_files import example
-```
-
-Now you should be able to run the following command.
-
-```python
-ray.get([example.example_function.remote(0) for _ in range(1000)])
-```