title: Value for HADOOP_CONF_DIR from Cluster
body: <p>I have setup a cluster(YARN) using Ambari with 3 VMs as hosts.</p>
  
  <p>Where I can find the value for HADOOP_CONF_DIR ?</p>
  
  <pre><code># Run on a YARN cluster
  export HADOOP_CONF_DIR=XXX
  ./bin/spark-submit \
    --class org.apache.spark.examples.SparkPi \
    --master yarn-cluster \  # can also be `yarn-client` for client mode
    --executor-memory 20G \
    --num-executors 50 \
    /path/to/examples.jar \
    1000
  </code></pre>