cluster-addr-in-use.js

var cluster = require('cluster');
var net = require('net');

// listen every second
if(process.env.WORKER || cluster.isWorker) {
  process.on('internalMessage', function(m) {
    console.log('worker receives', m);
  });

  listen();

  function listen() {
    var s = net.createServer();
    setTimeout(function() {
      s.listen(3000)
      .on('listening', function() {
        console.log('listening, close and try again');
        s.close(listen);
      })
      .on('error', function(er) {
        console.log('error:', er);
        listen();
      });
    }, 5000);
  }
} else {
  cluster.fork().process.on('internalMessage', function(m) {
    console.log('master receives', m);
  });
}

Do:

1. nc -l 3000 or `node -e 'require("net").createServer().listen(3000)'
2. node cluster-addr-in-use.js
3. ... worker can't listen
4. kill the node from (1)
5. ... worker still can't listen

even if code is changed so worker exits, and a new worker is fork()ed to try to listen again, it still never succeeds

the protocol/address/port key in the master server handles table is never cleared on listen failure, so once listen fails, listen will never succeed again.