Some nodes may resolve the hostname to the loopback address, while this is ok, it may generate a warning in the spark worker logs
The following error may be seen in the spark worker logs
WARN [Thread-378] 2015-06-11 13:41:39,712 ExternalLogger.java (line 73) SparkWorker: Your hostname, myhost1.somedomain.com resolves to a loopback address: 127.0.0.1; using 10.1.2.1 instead (on interface bond1)
WARN [Thread-378] 2015-06-11 13:41:39,714 ExternalLogger.java (line 73) SparkWorker: Set SPARK_LOCAL_IP if you need to bind to another address
The hostname resolved to the loopback address.
As the error suggests, add the SPARK_LOCAL_IP in the /etc/dse/spark/spark-env.sh file