title: Why are Spark executors trying to connect to spark_master instead of SPARK_MASTER_IP?
body: <p>Using a Spark 1.6.1 standalone cluster. After a system restart (and only minor config changes to /etc/hosts per worker) Spark executors suddenly started throwing errors that they couldn't connect to <code>spark_master</code>.</p>
  
  <p>When I <code>echo $SPARK_MASTER_IP</code> on the same shell used to start the master, it correctly identifies the host as <code>master.cluster</code>. And when I open the GUI at port <code>8080</code> it also identifies the master as <code>Spark Master at spark://master.cluster:7077</code>.</p>
  
  <p>I've also set in <code>spark-env.sh</code> the <code>SPARK_MASTER_IP</code> as well. Why are my executors trying to connect to <code>spark_master</code>?</p>