[erlang-bugs] epmd not cleaning up node name if node is down.

[Kenneth Lundin]

Hi,

The normal and correct behaviour is that a node is unregistered from
epmd when it is shutdown.
each Erlang node that register to epmd establishes and keep an open
tcp connection towards epmd.
When that connection is broken the Erlang node is unregistered.

On what OS is this?
How is the Erlang node shutdown?

I just run an example on Suse Linux where I create 2 Erlang nodes like this:

erl -sname a

and in another shell

erl -sname b

In a third shell epmd -names reported both nodes.

I then tried to terminate one of the nodes normally and epmd -names
correctly reported that there
is only one node left.

i started the second node again and epmd -names reported the 2 nodes.

I killed one of the nodes with kill -9 and again epmd -names reported
only one node as expected.

There must be something else causing the behaviour on your system.

/Kenneth Erlang/OTP team Ericsson

2008/8/15 Zbyszek Żółkiewski <zbyszek@REDACTED>:
> Hello,
>
> I have noticed that epmd is not cleaning node names if there are multiple
> nodes running on the same system and one of the node is shuted down.
> When i try to run node (jggtrans) In logs i can see:
>
> Aug 15 12:22:05 xmpp epmd: epmd: epmd running - daemon = 1
> Aug 15 12:22:05 xmpp epmd: epmd: node name already occupied jggtrans
> Aug 15 12:22:46 xmpp epmd: epmd: epmd running - daemon = 1
> Aug 15 12:22:46 xmpp epmd: epmd: node name already occupied jggtrans
>
> epmd - name:
>
> epmd: up and running on port 4369 with data:
> name jggtrans at port 46477
> name zero at port 58591
>
> while:
>
> netstat -plan | grep 58591
>
> tcp        0      0 0.0.0.0:58591           0.0.0.0:*
> LISTEN     2105/beam.smp
> tcp        0      0 213.134.161.163:58591   213.134.161.162:36438
> ESTABLISHED2105/beam.smp
>
> netstat -plan | grep 58591 gives nothing, actually node jggtrans is NOT
> running.
>
> The above problem makes running jggtrans node (after restart) imposible
> without killing epmd process - but it also requires of restarting all nodes
> in the system.
> I can reproduce this problem any time. What can cause it?
>
> thanks!
>
>
>
> --
> pozdrawiam,
> Zbyszek Żółkiewski
>
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