Unexpected behaviour of net_kernel
Wed Sep 1 23:02:26 CEST 2021
I played around with nodes in the last days, my experiments showed
So, no spurious nodeup/nodedown messages for not connected nodes..
Did you read the fine print in the documentation of
I would suspect some kind of race condition in your code.
Do you have timestamped logs which show when a node is shut down, and
when nodeup/down messages
On 01.09.21 13:00, Lorenzo Cian wrote:
> Dear all,
> I am a beginner in Erlang and I'm working on a project.
> I am working with nodes that need to connect and disconnect frequently
> both in "visible" and "hidden" mode.
> I wonder if there is a bug in net_kernel, because I observe the
> following unexpected behaviour and I'm unable to link it to any action
> caused by my code.
> What happens in the execution of my program is roughly the following:
> initial state: node A is connected (in visible mode) to node B,
> node D is not connected to any other node
> 1) node A disconnects from B (using net_kernel:disconnect/1)
> 2) node A connects to node D (using net_kernel:connect_node/1)
> result: somehow D receives nodeup messages and connects to both A and B
> expected behaviour: node D should connect to just A, while B should be
> connected to no one
> Note that steps 1 and 2 are executed sequentially in the same function
> so there's no way they could be concurrent.
> Could this be a bug in net_kernel?
> I thought that maybe, somehow A has some messages related to
> net_kernel that hang up in a way such that when step 2 happens, node A
> is not yet disconnected completely from B?
> Is it possible that something like that happens? If yes, how can I
> avoid this?
> Even if I'm pretty confident that my code works as intended and I
> tried to debug and check it several times, of course the other option
> is that this could be caused by a bug in my code.
> Of course there are a lot of other processes involved that I can't
> explain here, but let's suppose that they don't cause any interference
> with the example.
> I hope someone who knows Erlang better than me can help me clarify my
> Thank you,
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