Pyspark.sql.utils.IllegalArgumentException: u'java.net.UnknownHostException:

Question

I am new to Pyspark and I am trying to make a simple account. However, this gives me this error. The text file is inside hdfs.

CODE:

>>> mydata = sc.textFile("hdfs://user/poem.txt")
>>> mydata.count()

ERROR:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  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'

Answer 1

You are lacking "/"

r = sc.textFile("hdfs://user/myFile")
r.count()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/cloudera/parcels/CDH-5.7.0-1.cdh5.7.0.p1464.1349/lib/spark/python/pyspark/rdd.py", line 1004, in count
    return self.mapPartitions(lambda i: [sum(1 for _ in i)]).sum()
  File "/opt/cloudera/parcels/CDH-5.7.0-1.cdh5.7.0.p1464.1349/lib/spark/python/pyspark/rdd.py", line 995, in sum
    return self.mapPartitions(lambda x: [sum(x)]).fold(0, operator.add)
  File "/opt/cloudera/parcels/CDH-5.7.0-1.cdh5.7.0.p1464.1349/lib/spark/python/pyspark/rdd.py", line 869, in fold
    vals = self.mapPartitions(func).collect()
  File "/opt/cloudera/parcels/CDH-5.7.0-1.cdh5.7.0.p1464.1349/lib/spark/python/pyspark/rdd.py", line 771, in collect
    port = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
  File "/opt/cloudera/parcels/CDH-5.7.0-1.cdh5.7.0.p1464.1349/lib/spark/python/lib/py4j-0.9-src.zip/py4j/java_gateway.py", line 813, in __call__
  File "/opt/cloudera/parcels/CDH-5.7.0-1.cdh5.7.0.p1464.1349/lib/spark/python/pyspark/sql/utils.py", line 53, in deco
    raise IllegalArgumentException(s.split(': ', 1)[1], stackTrace)
pyspark.sql.utils.IllegalArgumentException: u'java.net.UnknownHostException: user'

However, if you do

>>> r = sc.textFile("hdfs:///user/myFile")
>>> r.count()
318199

this is because hdfs: // is a URI. And in a fully qualified syntax, this should be hdfs: ///. Therefore, Spark thinks the token "user" as an NN-Host