Master was disconnecting its workers as soon as they both started up.
Meanwhile, the workers were trying to listen. Its a race, sometimes the
disconnect would happen between when worker gets the response message,
and acks that message with a 'listening'. This worked OK after v0.11
introduced a behaviour where disconnect would always exit the worker,
but once that backwards-incompatible behaviour is removed, the worker
lives long enough to try and respond to the master, and child_process
errors at the attempt to send from a disconnected child.
Implement support for debugging cluster workers. Each worker process
is assigned a new debug port in an increasing sequence.
I.e. when master process uses port 5858, then worker 1 uses port 5859,
worker 2 uses port 5860, and so on.
Introduce new command-line parameter '--debug-port=' which sets debug_port
but does not start debugger. This option works for all node processes, it
is not specific to cluster workers.
Fixesjoyent/node#5318.
Sam Roberts
Ben Noordhuis
Miroslav Bajtoš