[erlang-questions] Get cookie time-out

[Olivier BOUDEVILLE]

Thanks Ali and Antoine for your answer! I guess we will indeed use a 
finite, yet increased, time-out for that. 

This is the first time we will have to patch our Erlang version though; 
hopefully, as the scale increases, other exchanges will not require 
hardcoded time-outs to be modified.
As I see it, in some cases, time-outs have indeed to be set to actual 
values (not infinity, for example to overcome hardware faults), but then 
these values are arbitrary and context-dependent.

In our user code we ended up defining profiles (development/production), 
as no single set of values could be used in all contexts. Depending on how 
many constant time-out values are lurking in the Erlang code itself, maybe 
it could be useful to do the same there?

Not strictly related, but still in the proper distributed initialization 
of Erlang nodes, is there any feedback of the Erlang maintaining team 
about the code_server:call/2  suspected race condition ? 
(http://erlang.2086793.n4.nabble.com/code-server-call-2-problem-td3387884.html) 


Thanks again,
Best regards,

Olivier Boudeville.
---------------------------
Olivier Boudeville

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antoine.koener@REDACTED 
07/06/2011 16:25

A
ali.sabil@REDACTED
cc
olivier.boudeville@REDACTED, erlang-questions@REDACTED
Objet
Re: [erlang-questions] Get cookie time-out







On Jun 7, 2011, at 16:21 , Ali Sabil wrote:

> Hi,
>
> On Tue, Jun 7, 2011 at 2:51 PM, Olivier BOUDEVILLE
> <olivier.boudeville@REDACTED> wrote:
>>
>> Hello,
>>
>> We are running a distributed application over a cluster and 
>> recently, during
>> its deployment over 45 nodes, we have encountered a time-out 
>> apparently
>> related to the inter-node cookie retrieval:
>> "{timeout,{gen_server,call,[auth,{get_cookie,'SOME_NODE...".
>>
>> We are not that familiar with OTP, but apparently there could be a 
>> way of
>> specifying a time-out for such an internal gen_server: we have 
>> indeed in
>> lib/kernel/src/auth.erl:
>>
>> """
>> start_link() ->
>>     gen_server:start_link({local, auth}, auth, [], []).
>> """
>>
>> I suppose we could add a {timeout,Time} option there ? (there must 
>> be a
>> default time-out, even if I do not know its value)
>
> The default timeout value for gen_server:call() is 5000 ms, maybe you
> could try replacing the gen_server:call/2 with a gen_server:call/3 in
> lib/kernel/src/auth.erl so that:
> """
> get_cookie(Node) ->
>    gen_server:call(auth, {get_cookie, Node}).
> """
>
> becomes:
> """
> get_cookie(Node) ->
>    gen_server:call(auth, {get_cookie, Node}, infinity).
> """

Take care that doing so means that the calling process will be 
blocked...
I'm not sure that this will fix anything.

Instead of infinity, may be increase the timeout, why not 60000 (1 
minute) ?





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