[erlang-questions] Reconnect to nodes

[Roberto Ostinelli]

Thank you both for confirming.
Hence I guess some kind of a basic reconnection manager might be helpful
here.

Thanks!

r.

On Fri, Apr 22, 2016 at 12:35 PM, Serge Aleynikov <serge@REDACTED>
wrote:

> Roberto,
>
> This is the expected behavior. Note that the nodes will automatically
> reconnect by default when either node has a process that sends a message to
> a process on the remote node.  This reconnection behavior can be modified
> by setting the kernel's 'dist_auto_connect' option.
>
> Other applications (such as mnesia) may require custom recovery from a
> network split, which is one of the reasons why automatic reconnection may
> not be desirable.
>
> Regards,
>
> Serge
>
> On Fri, Apr 22, 2016 at 5:39 AM, Roberto Ostinelli <roberto@REDACTED>
> wrote:
>
>> Dear list,
>> A simple question: am I correct that, when a node is removed because of a
>> net split, you need to have your own application logic to reconnect to it,
>> and nothing in the VM will try doing that for you?
>>
>> Let me show you an example. I have two nodes: 1@REDACTED and 2@REDACTED
>> that are connected to each other:
>>
>> (1@REDACTED)1> nodes().
>> ['2@REDACTED']
>>
>> On node 2 I listen for nodedown events of node 1:
>>
>> (2@REDACTED)1> monitor_node('1@REDACTED', true).
>> true
>>
>> On node 1, I simulate a net splits with the best option I've found until
>> now, i.e suspending the net_kernel process:
>>
>> (1@REDACTED)2> sys:suspend(net_kernel).
>> ok
>>
>> After ~60 seconds on node 2 I get:
>>
>> =ERROR REPORT==== 22-Apr-2016::11:28:21 ===
>> ** Node '1@REDACTED' not responding **
>> ** Removing (timedout) connection **
>> (2@REDACTED)2> flush().
>> Shell got {nodedown,'1@REDACTED'}
>>
>> Now the two nodes are disconnected:
>>
>> (1@REDACTED)3> nodes().
>> []
>>
>> (2@REDACTED)3> nodes().
>> []
>>
>> Even when I resume the net_kernel process:
>>
>> (1@REDACTED)4> sys:resume(net_kernel).
>> ok
>>
>> The nodes do not reconnect:
>>
>> (1@REDACTED)5> nodes().
>> []
>>
>> I'm ok with this, though I would like to confirm that my understanding is
>> correct.
>> If so, does everyone just implement some standard connection manager that
>> does only reconnections?
>>
>> Thank you,
>> r.
>>
>>
>>
>>
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>>
>>
>
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