title: What does setMaster `local[*]` mean in spark?
body: <p>I found some code to start spark locally with:</p>
  
  <pre><code>val conf = new SparkConf().setAppName("test").setMaster("local[*]")
  val ctx = new SparkContext(conf)
  </code></pre>
  
  <p>What does the <code>[*]</code> mean?</p>