title: What to set `SPARK_HOME` to?
body: <p>Installed apache-maven-3.3.3, scala 2.11.6, then ran:</p>
  
  <pre><code>$ git clone git://github.com/apache/spark.git -b branch-1.4
  $ cd spark
  $ build/mvn -DskipTests clean package
  </code></pre>
  
  <p>Finally:</p>
  
  <pre><code>$ git clone https://github.com/apache/incubator-zeppelin
  $ cd incubator-zeppelin/
  $ mvn install -DskipTests
  </code></pre>
  
  <p>Then ran the server:</p>
  
  <pre><code>$ bin/zeppelin-daemon.sh start
  </code></pre>
  
  <p>Running a simple notebook beginning with <code>%pyspark</code>, I got an error about <code>py4j</code> not being found. Just did <code>pip install py4j</code> (<a href="https://stackoverflow.com/q/26533169">ref</a>).</p>
  
  <p>Now I'm getting this error:</p>
  
  <pre><code>pyspark is not responding Traceback (most recent call last):
    File "/tmp/zeppelin_pyspark.py", line 22, in &lt;module&gt;
      from pyspark.conf import SparkConf
  ImportError: No module named pyspark.conf
  </code></pre>
  
  <p>I've tried setting my <code>SPARK_HOME</code> to: <code>/spark/python:/spark/python/lib</code>. No change.</p>