MB-47702: Optionally register node with epmd.

Do not crash if fail to register with epmd, we might have killed it.

Change-Id: Ia6abb52fd34c361e3168a2907c5f049abb4e890d
Reviewed-on: http://review.couchbase.org/c/ns_server/+/158664
Well-Formed: Build Bot <[email protected]>
Tested-by: Abhijeeth Nuthan <[email protected]>
Reviewed-by: Timofey Barmin <[email protected]>

Author: anuthan

src/cb_dist.erl

@@ -597,10 +597,8 @@ listen_proto({AddrType, Module}, NodeName) ->
         fun () ->
                 case Module:listen(NodeName) of
                     {ok, _} = Res ->
-                        case maybe_register_on_epmd(Module, NodeName, Port) of
-                            ok -> Res;
-                            {error, _} = Error -> Error
-                        end;
+                        maybe_register_on_epmd(Module, NodeName, Port),
+                        Res;
                     Error -> Error
                 end
         end,
@@ -636,9 +634,14 @@ maybe_register_on_epmd(Module, NodeName, PortNo)
         ns_server ->
             Family = proto_to_family(Module),
             case erl_epmd:register_node(NameStr, PortNo, Family) of
-                {ok, _} -> ok;
-                {error, already_registered} -> ok;
-                Error -> Error
+                {ok, _} ->
+                    ok;
+                {error, already_registered} ->
+                    ok;
+                Error ->
+                    info_msg("Failed to register ~p with epmd. Reason ~p",
+                             [{NodeName, PortNo, Family}, Error]),
+                    Error
             end;
         _ ->
             ok