Newbie node question

Ulf Wiger <>
Thu Mar 16 11:12:55 CET 2000


On Thu, 16 Mar 2000, Sean Hinde wrote:

Sean>Kiciak,
Sean>
Sean>> First, sorry if it's a stupid question, I'm REALLY a beginner in
Sean>> Erlang...
Sean>
Sean>We've all been there
Sean>
Sean>> If I have 2 nodes A and B, and both "know" each other (B is in the
Sean>> nodes() of A and vice-versa).
Sean>> Is it possible for a node C no connect to A without having B in it's
Sean>> nodes() list ?
Sean>> I saw there is a disconnect_node function, but I can't find a
Sean>> connect_node one...
Sean>
Sean>Normally all nodes in an erlang system are fully meshed, so
Sean>the act of connecting node C to either A or B will
Sean>automatically connect them all together.
Sean>
Sean>The 'connect' command is net_adm:ping().

But it is also possible to disable the "connect-all" semantics.
Unfortunately, this has the side-effect that you cannot use
global name registration.

Quote from erl -man global:

     The server also performs the critical task  of  continuously
     monitoring  changes  in  node configuration, if a node which
     runs a globally registered process goes down, the name  will
     be  globally  unregistered.  The server will also maintain a
     fully connected network. For example, if node N1 connects to
     node  N2  (which  is  already  connected  to N3), the global
     server on N1 then N3 will make sure that also N1 and N3  are
     connected.  If  this  is  not desired, the command line flag
     -connect_all false must be passed to init at boot  time.  In
     this  case,  the  name  registration facility cannot be used
     (but the lock mechanism will still work.)

So, to disable connect_all, try erl -connect_all false

I recommend that you don't do this, though. It might have 
unexpected consequences. We at AXD 301 are trying to figure out
ways to evolve from the connect_all philosophy without losing 
any central features of Erlang. I can't give you an ETOC on this.

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <>
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