[IPython-User] ipcluster in ssh mode -

Manuel Jung mjung@astrophysik.uni-kiel...
Mon Aug 8 16:30:15 CDT 2011


This is awesome! Thanks a lot! I gave your latest ipython git version a test
and the registration with ssh tunneling for engines works. But i am not able
to process any tasks. I get:

rc.ids==[0]
rc[:].map_sync(lambda x: x**2, range(10))

... does not return! Also no load on the engine is registered. How can i
debug this? There is no output on the ipcluster log.

Could you explain, why there are 6 instances of ipengine showing up in htop
on my cluster node? (n==1)

Also i get some failing tunnel setups for n>1, but let us focus on n==1 for
now.




2011/8/8 MinRK <benjaminrk@gmail.com>

> As I mentioned, it was quite straightforward to add tunneling support, at
> least for the simplest case:
>
> https://github.com/ipython/ipython/pull/685
>
> :)
>
> -MinRK
>
>
> On Sun, Aug 7, 2011 at 15:17, MinRK <benjaminrk@gmail.com> wrote:
>
>>
>>
>> On Sun, Aug 7, 2011 at 14:25, Manuel Jung <mjung@astrophysik.uni-kiel.de>wrote:
>>
>>> Well no answers yet, but i made some progression.
>>>
>>> I was not able to work around the error, but i think i understand now,
>>> why this does not work.
>>>
>>> The error appears, because the registration is successfull, but
>>> everything else like heartbeat etc. fails. For these operations were no
>>> ports forwarded.
>>>
>>> It is stated here
>>>
>>>
>>> http://ipython.org/ipython-doc/stable/parallel/parallel_securitystandard.html#ssh<http://ipython.org/ipython-doc/stable/parallel/parallel_security.html#ssh>
>>>
>>> that tunneling for engines (which i tried) is not supported atm. I tried
>>> to work around this, but only created a tunnel for the registration socket -
>>> not for the other sockets, which are used by the engines. An overview of
>>> them is given here:
>>>
>>>
>>> http://ipython.org/ipython-doc/stable/development/parallel_connections.html#all-connections
>>>
>>> Well i did specify the registration port, but i did not specify ports
>>> heartbeats etc. Am i able to do this to get homebrew engine tunneling? I saw
>>> a bunch of options which are maybe related in the configuration for the
>>> controller, but did'nt quite understud, which ones i had to alter.
>>>
>>> Maybe someone could point out, why there is no tunneling support for
>>> engines there (yet)? Is there any particular reason for this, other than
>>> just nobody did it yet?
>>>
>>
>>  Correct, some amount of ssh tunneling will be added to the engine, it
>> just hasn't been done.  The reason it's a lower priority than the
>> client-controller connections is just that it's more rare that engines can't
>> see the controller directly.  It's also slightly less valuable, because
>> engines are often run in environments that cannot accept input, so only
>> passwordless ssh will work.  The client tunnels allow for input of a
>> password (though I doubt that it works in every case).
>>
>>
>> As it stands now, there's no way to tell the engine to ignore the
>> connection reply from the controller (which contains all of the
>> non-registration connection info), so there are some restrictions on how you
>> can trick the engine into connecting to different ports.  Essentially you
>> will have to set up all 6 forwarded ports, and the Controller must be
>> listening on localhost (can be in addition to localhost, e.g. 0.0.0.0 for
>> all interfaces).
>>
>> Prevent the JSON connector file from disambiguating localhost connections
>> to the controller's external IP by specifying loopback, e.g.:
>>
>> ipcontroller --ip=0.0.0.0 --location=127.0.0.1
>>
>> That way, engines will always try to connect to localhost, regardless of
>> where the Controller actually is running, enabling them to use your tunnels.
>>
>> First, you must specify (or retrieve from the controller's debug output)
>> all of the ports the controller is listening on for engine connections:
>>
>> in ipcontroller_config.py:
>> # port-pairs:
>> c.HubFactory.iopub
>> c.HubFactory.hb
>> c.HubFactory.task
>> c.HubFactory.mux
>> c.HubFactory.control
>>
>> Then you can specify the tunnels manually (the local ports *must* be the
>> same, for now). That will be the first port of each Queue (iopub, task, mux,
>> control) and both hb ports, and the registration port.
>>
>> So, I was able to get this running with the following commands:
>>
>> 1. start the controller, listening on all interfaces and forcing loopback
>> IP for disambiguation:
>>
>>  [controller] $> ipcontroller --ip=0.0.0.0 --location=127.0.0.1
>> --port=10101 --HubFactory.hb=10102,10112 --HubFactory.control=10203,10103
>> --HubFactory.mux=10204,10104 --HubFactory.task=10205,10105
>>
>> # (with this pattern, 101XY ports are ports visible to the engine, 102XY
>> are client-only)
>>
>> 2. Set up forwarded ports on the engines.
>>
>> [engine] $> for port in 10101 10102 10112 10103 10104 10105; do ssh
>> $server -f -N -L $port:$controller:$port; done
>>
>> In my case, $server was a third machine that I have ssh access to that has
>> access to $controller, where the controller process is running.  If you are
>> tunneling directly, then $server would be the controller's IP, and
>> $controller would be 127.0.0.1
>>
>> 3. connect the engine
>>
>> [engine] $>  ipengine --f=/path/to/ipcontroller-engine.json
>>
>> # note that if you are on a shared filesystem, just `ipengine` should
>> work.
>>
>> Implementing support for the easiest case should be quite straightforward,
>> and less tedious than this. (Pull requests welcome!).
>>
>> I hope that helps.
>>
>> -MinRK
>>
>>
>>> Thanks!
>>> Manuel
>>>
>>> _______________________________________________
>>> IPython-User mailing list
>>> IPython-User@scipy.org
>>> http://mail.scipy.org/mailman/listinfo/ipython-user
>>>
>>>
>>
>
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