[nanomsg] Re: How to bind on a random port?
- From: "xreborner (Shixi Chen)" <xreborner@xxxxxxxxx>
- To: nanomsg@xxxxxxxxxxxxx
- Date: Sat, 15 Nov 2014 23:28:42 +0800
The problem is that, if it fails, it just aborts. So no chance to retry.
On Sat, Nov 15, 2014 at 4:21 PM, Jason E. Aten <j.e.aten@xxxxxxxxx> wrote:
> This.
>
> Echoing Matt's comment -- I just bind to port 0 using non-nanomsg socket
> calls (so the kernel picks a free port). Then I note the port, then close
> that socket and reopen on that port in nanomsg. Since there is still a
> short period in which that port might get taken, I also retry if again that
> fails, but usually it succeeds.
>
>
> On Fri, Nov 14, 2014 at 4:51 PM, Matt Howlett <matt.howlett@xxxxxxxxx>
> wrote:
>
>>
>> The behavior of nn_bind was also unexpected me. My work-around is to find
>> a free port outside of nanomsg, then immediately bind to it. I stagger the
>> start up of my workers (~1 worker per core per machine) so in practice I
>> never get a race condition. Not ideal, but it works. If you can control
>> when all of the processes that bind to random ports start up on each node,
>> you can do the same thing, though it sounds like your situation might be
>> more difficult.
>>
>>
>>
>> On Fri, Nov 14, 2014 at 10:30 PM, xreborner (Shixi Chen) <
>> xreborner@xxxxxxxxx> wrote:
>>
>>> Unfortunately, I'm running a distributed computation application on a
>>> cluster with thousands of machines, in each machine there could be multiple
>>> tasks are running in background and have occupied some random ports. If I
>>> just choose a random port (in fact, i use not only one port) and use it,
>>> there are roughly 1% probability to fail in one machine. If my application
>>> is running on 200 machines, then it almost always fail.
>>>
>>> On Fri, Nov 14, 2014 at 11:05 PM, Martin Sustrik <sustrik@xxxxxxxxxx>
>>> wrote:
>>>
>>>> -----BEGIN PGP SIGNED MESSAGE-----
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>>>> On 14/11/14 15:55, xreborner (Shixi Chen) wrote:
>>>> > So, if i don't know any port numbers that are available, it is
>>>> > impossible to use nanomsg?
>>>>
>>>> Yes. Although on a typical machine, almost all ports are unused, so
>>>> just picking one and using it tends to work.
>>>>
>>>> > My program is to be run on a remote cluster, where no port numbers
>>>> > are known to be reserved. I was using zeromq and my solution was to
>>>> > repeat calling zmq_bind. I'm considering to switch to nanomsg since
>>>> > it looks better (and also due to some problems in zeromq). Is there
>>>> > any plan to solve this problem in the future?
>>>>
>>>> I was thinking of implementing tcpmux (RFC 1) but it's not coming any
>>>> time soon.
>>>>
>>>> Martin
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>>>>
>>>
>>
>
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