[erlang-questions] two epmds running

Garrett Smith <>
Tue Mar 16 17:10:45 CET 2010


On Tue, Mar 16, 2010 at 9:36 AM, Bob Ippolito <> wrote:
> On Tue, Mar 16, 2010 at 2:23 AM, Anthony Shipman <> wrote:
>> Sometimes it happens that I discover two epmd processes running. One of
>> them is in a tight loop consuming 100% of CPU time. My guess is that the
>> second one is started automatically because the first one is no longer
>> responding. Is this a known bug in epmd?
>
> I think we have seen this before, one of them is probably violently
> logging "epmd: epmd: error in accept" as well. We have only seen this
> on boot-up of a machine, probably due to several Erlang VMs trying to
> start up at the same time. We don't currently have a solution for this
> issue (mostly because we don't know the root cause yet).
>
> I am not sure we get two of them, it might be just one in our case.

I haven't seen two running, but I've seen none running, which is a
real bummer. I've written a monitor process (probably gen_fsm based)
that keeps an eye on epmd and starts it and reinitializes it when it
goes away. A properly functioning epmd is important enough that you
might consider something similar to ensure that, in your case, that
rogue process is dealt with (killed?).

I suppose that's somewhat flippant -- to say write your own monitor
for this, but losing epmd is like losing your network and people go to
great lengths to keep networks up.

Garrett


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