title: Multiple workers on a single machine for different tasks
body: <p>I'm trying to build a distributed job execution system with celery. </p>
  
  <p>When I launch 2 workers on a single machine (localhost), in which one for an addition task <code>add</code> and the other for a subtraction task <code>sub</code>, then use <code>add.delay()</code> to kick off sevral addition tasks, there's an error in the subtraction worker's terminal:</p>
  
  <p><code>[2013-03-05 15:51:18,898: ERROR/MainProcess] Received unregistered task of type 'add_tasks.add'.</code></p>
  
  <p>In this test, I kicked off 2 addition tasks: one is caught by the addition worker while the other caught by the subtraction worker, which caused the error above. How could I change the configurations so that the second addition task won't be caught by the subtraction worker? Thanks.</p>
  
  <p>Here's the code:</p>
  
  <p><code>add_tasks.py:</code></p>
  
  <pre><code>celery = Celery('add_tasks', backend='amqp', broker='amqp://guest@localhost//')
  
  @celery.task
  def add(x, y):
      sleep(20)
      return x + y
  </code></pre>
  
  <p><code>sub_tasks.py:</code></p>
  
  <pre><code>celery = Celery('sub_tasks', backend='amqp', broker='amqp://guest@localhost//')
  
  @celery.task
  def sub(x, y):
      sleep(10)
      return x - y
  </code></pre>
  
  <p>I launched the workers by <code>celery -A add_tasks worker --loglevel=info -n worker1</code> and <code>celery -A sub_tasks worker --loglevel=info -n worker2</code> in two terminals of localhost machine.</p>