epmd daemon runs after riak stops

Ciprian Dorin Craciun ciprian.craciun at gmail.com
Tue Oct 16 12:49:44 EDT 2012


On Tue, Oct 9, 2012 at 12:31 AM, David Lowell <dave at go2ctv.com> wrote:
> I would like to understand better why '/etc/init.d/riak stop' stops riak,
> but the 'epmd' daemon continues to run. I would have hoped that when I
> administratively stop riak on a node that all its various cogs would stop
> turning.
>
> Furthermore, I'm not clear on how the lifecycle of epmd is controled. Is it
> started by any Erlang process that runs, and never stopped?
>
> I would appreciate any insights folks could offer. Thanks!

    Indeed this is a very annoying Erlang behaviour, especially when
running in container environments or highly controlled / automated
ones.

    If you are interested in finding more about both the "details" and
possible hacks, please see my previous posts (both here and on Erlang
mailing list):
    http://lists.freedesktop.org/archives/systemd-devel/2012-August/006273.html
    http://lists.basho.com/pipermail/riak-users_lists.basho.com/2012-June/008608.html
    http://erlang.org/pipermail/erlang-questions/2011-October/062004.html
    http://erlang.org/pipermail/erlang-questions/2011-October/061893.html

    In short the solution is:
    * trick the erlang process not to start epmd itself; (see the last
link above;)
    * run epmd yourself as a separate service;

    Ciprian.




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