启动pyspark，报错socket.gaierror: [Errno -2] Name or service not known

启动pyspark报错，如下：

[root@hadoop-senior spark-1.6.0-cdh5.13.0]# pyspark
Python 2.6.6 (r266:84292, Aug 18 2016, 15:13:37) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel).
18/09/17 10:39:29 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
18/09/17 10:39:30 WARN SparkConf: 
SPARK_WORKER_INSTANCES was detected (set to '1').
This is deprecated in Spark 1.0+.

Please instead use:
 - ./spark-submit with --num-executors to specify the number of executors
 - Or set SPARK_EXECUTOR_INSTANCES
 - spark.executor.instances to configure the number of instances in the spark config.
        
Traceback (most recent call last):
  File "/opt/cdh5.13.0/spark-1.6.0-cdh5.13.0/python/pyspark/shell.py", line 43, in 
    sc = SparkContext(pyFiles=add_files)
  File "/opt/cdh5.13.0/spark-1.6.0-cdh5.13.0/python/pyspark/context.py", line 115, in __init__
    conf, jsc, profiler_cls)
  File "/opt/cdh5.13.0/spark-1.6.0-cdh5.13.0/python/pyspark/context.py", line 176, in _do_init
    self._accumulatorServer = accumulators._start_update_server()
  File "/opt/cdh5.13.0/spark-1.6.0-cdh5.13.0/python/pyspark/accumulators.py", line 259, in _start_update_server
    server = AccumulatorServer(("localhost", 0), _UpdateRequestHandler)
  File "/usr/lib64/python2.6/SocketServer.py", line 412, in __init__
    self.server_bind()
  File "/usr/lib64/python2.6/SocketServer.py", line 423, in server_bind
    self.socket.bind(self.server_address)
  File "", line 1, in bind
socket.gaierror: [Errno -2] Name or service not known
>>> 

解决方法：在/etc/hosts添加“127.0.0.1    localhost”这个映射