[erlang-questions] Distributed erlang problem

[Serge Aleynikov]

When you are starting db1@REDACTED{1,2}-rep are you binding distributed 
Erlang to the "rep" interface's IP address or using the default 
(0.0.0.0)?  If the former then you wouldn't have a way for OMC to 
connect to either node unless the connections are originated by the 
db1@REDACTED{1,2}-rep nodes to OMC.  A work around could be to use a 
separate gen_tcp (udp?) server listening on the "oam" interface and roll 
out a custom protocol so that would detect incoming connection requests 
(that are not based on Erlang's distribution), and cause 
db1@REDACTED{1,2}-rep nodes to initiate connections to OMC.

If you are binding the "rep" nodes to 0.0.0.0 then there shouldn't be 
any issue connecting from OMC unless there's a firewall restriction.

These links might be helpful:

http://www.erlang.org/pipermail/erlang-patches/2008-March/000236.html
http://www.erlang.org/pipermail/erlang-patches/2008-March/000240.html

Serge

Chandru wrote:
> I am having a hard time figuring out how to get a few nodes to talk to each
> other within certain rules. See figure below. Each box is a separate
> physical server. The small boxes inside each big box are LAN cards.
> 
>   +------------------+        +------------------+
>   |               +--+        +--+               |
>   | db1@REDACTED |  |........|  | db1@REDACTED |
>   |               +--+        +--+               |
>   |    +-oam--+      |        |       +-oam-+    |
>   +----+--+---+------+        +-------+--+--+----+
>           |                              |
>           |                              |
>           |                              |
>           |                              |
>           |      +-------------------+   |
>           |      |                   |   |
>           |      |                   |   |
>           +------+       OMC         ....|
>                  |                   |
>                  |                   |
>                  +-------------------+
> 
> 
> I've got two database nodes on two hosts, each of which have two LAN cards.
> One set of LAN cards are called the replication interfaces; they connect via
> a special LAN which is very low latency and high bandwidth. This is used for
> mnesia replication. To enable this, I start the DB nodes with the -sname
> parameter set to 'db1@REDACTED'.
> 
> Now there is a separate OMC node which should talk to the DB nodes via
> distributed erlang on another set of interfaces. The problem is that the
> 'host1-rep' interface is not reachable from the OMC host (due to security
> issues). Only the 'host1-oam' interface is reachable. But, on the OMC node,
> 'db1@REDACTED' is an unknown node.
> 
> It seems that I need a feature where an erlang node on a machine can be
> reached via multiple  names, such as 'db1@REDACTED', 'db1@REDACTED', '
> db1@REDACTED, but I doubt this capability exists.
> 
> Any suggestions? Anyone else had similar issues to deal with?
> 
> regards,
> Chandru
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> erlang-questions mailing list
> erlang-questions@REDACTED
> http://www.erlang.org/mailman/listinfo/erlang-questions