[erlang-questions] Erlang inter node communication issue

Adrian Roe <>
Sat Aug 31 08:00:33 CEST 2013


In addition to Erik's comments, one thing we have found on ec2 instances is that you have to be particularly careful to ensure erlang nodes come up with the nodes' public IP addresses (for example we've never had any luck with erl -sname myname..., only explicitly using erl -name )

It's worth a little hassle at the start - erlang and ec2 were made for each other :)

Adrian

Sent from my iPhone

On 31 Aug 2013, at 00:59, Erik Søe Sørensen <> wrote:

> For one thing, you should be aware that while EPMD is part of the the process, and therefore that it's true that its port should be accessible, the inter-node connection does not go through EPMD.
> For you, this probably means that you need to open other ports.
> Erlang can be told to use a port in a specific range - the "how" is described, for instance, here:
>   https://sites.google.com/site/gettingalongwitherlang/home/distributed-programming/port-range-for-erlang-distribution-protocol
> the short version being: add the parameters
>   -kernel inet_dist_listen_min ${FROM} inet_dist_listen_max ${TO}
> If I'm guessing correctly, you'll need to pick a port range, add those parameters to "erl", and open for the ports in that range.
> 
> (To find out if I'm guessing correcly: run "epmd -names" on host A; this will tell you the port number of your Erlang node. Then, on host B, check if you can connect to that port, using e.g. "telnet A <port>".)
> 
> Hoping this helps
> /Erik
> 
> 
> 2013/8/30 David Chamard <>
>> Hi Everyone,
>> 
>> I am unable to get 2 erlang nodes to talk to each other through net_adm:ping.
>> I am running on centos 6.3 and I am on amazon ec2.
>> 
>> Port 4369 is open and I can telnet to it from both servers
>> 
>> The cookies are the same when I do a get_cookie.
>> When I try to do a net_adm:ping it hangs for a while and return a pang.
>> I can resolve the hostname properly.
>> 
>> Anyone could guide me on what the issue could be?
>> 
>> Thank you,
>> 
>> David
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>> 
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