title: pyspark.sql.utils.IllegalArgumentException: u'java.net.UnknownHostException: user'
body: <p>I am new to Pyspark and I am trying to do a simple count. However it is giving me this error. The text file is inside hdfs. </p>
  
  <p>CODE:</p>
  
  <pre><code>&gt;&gt;&gt; mydata = sc.textFile("hdfs://user/poem.txt")
  &gt;&gt;&gt; mydata.count()
  </code></pre>
  
  <p>ERROR:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/local/lib/spark-2.0.1-bin-hadoop2.7/python/pyspark/rdd.py", line 1008, in count
      return self.mapPartitions(lambda i: [sum(1 for _ in i)]).sum()
    File "/usr/local/lib/spark-2.0.1-bin-hadoop2.7/python/pyspark/rdd.py", line 999, in sum
      return self.mapPartitions(lambda x: [sum(x)]).fold(0, operator.add)
    File "/usr/local/lib/spark-2.0.1-bin-hadoop2.7/python/pyspark/rdd.py", line 873, in fold
      vals = self.mapPartitions(func).collect()
    File "/usr/local/lib/spark-2.0.1-bin-hadoop2.7/python/pyspark/rdd.py", line 776, in collect
      port = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
    File "/usr/local/lib/spark-2.0.1-bin-hadoop2.7/python/lib/py4j-0.10.3-src.zip/py4j/java_gateway.py", line 1133, in __call__
    File "/usr/local/lib/spark-2.0.1-bin-hadoop2.7/python/pyspark/sql/utils.py", line 79, in deco
      raise IllegalArgumentException(s.split(': ', 1)[1], stackTrace)
  pyspark.sql.utils.IllegalArgumentException: u'java.net.UnknownHostException: user'
  </code></pre>