title: java.net.UnknownHostException when starting Spark shell
body: <p>After installing spark following this.
  <a href="https://www.davidadrian.cc/posts/2017/08/how-to-spark-cluster/" rel="nofollow noreferrer">https://www.davidadrian.cc/posts/2017/08/how-to-spark-cluster/</a></p>
  
  <p>I got this message :</p>
  
  <pre><code>n@jupyter:~$ spark-shell
  Using Spark's default log4j profile: org/apache/spark/log4j-defaults.properties
  Setting default log level to "WARN".
  To adjust logging level use sc.setLogLevel(newLevel). For SparkR, use setLogLevel(newLevel).
  java.net.UnknownHostException: jupyter: jupyter: Name or service not known
    at java.net.InetAddress.getLocalHost(InetAddress.java:1505)
    at org.apache.spark.util.Utils$.findLocalInetAddress(Utils.scala:891)
    at org.apache.spark.util.Utils$.org$apache$spark$util$Utils$$localIpAddress$lzycompute(Utils.scala:884)
    at e(Utils.scala:941)
        ____              __
       / __/__  ___ _____/ /__
      _\ \/ _ \/ _ `/ __/  '_/
     /___/ .__/\_,_/_/ /_/\_\   version 2.2.0
        /_/
  
  Using Scala version 2.11.8 (OpenJDK 64-Bit Server VM, Java 1.8.0_112-release)
  
  scala&gt; 1+1
  res0: Int = 2
  </code></pre>
  
  <p>I am not sure why spark is looking for jupyter class, 
  since this is only shell launching.</p>
  
  <p>EDIT :
  Add bashrc config.</p>
  
  <pre><code>export PATH=/home/noel/pycharm/jre/bin:$PATH
  
  export HADOOP_HOME=/home/xxx/hadoop_275
  export LD_LIBRARY_PATH=$HADOOP_HOME/lib/native:$LD_LIBRARY_PATH
  
  export SPARK_HOME=/home/xxx/spark/spark22_hadoop27
  export PATH=$SPARK_HOME/bin:$PATH
  </code></pre>
  
  <p>etc/host :</p>
  
  <pre><code>127.0.0.1   localhost
  #127.0.1.1  deep-learning
  
  # The following lines are desirable for IPv6 capable hosts
  ::1     ip6-localhost ip6-loopback
  fe00::0 ip6-localnet
  ff00::0 ip6-mcastprefix
  ff02::1 ip6-allnodes
  ff02::2 ip6-allrouters
  </code></pre>