1 files changed, 4 insertions, 0 deletions
diff --git a/ec2/spark_ec2.py b/ec2/spark_ec2.py
index 9fd652a3df..84a950c9f6 100755
--- a/ec2/spark_ec2.py
+++ b/ec2/spark_ec2.py
@@ -1242,6 +1242,10 @@ def get_ip_address(instance, private_ips=False):
 def get_dns_name(instance, private_ips=False):
     dns = instance.public_dns_name if not private_ips else \
         instance.private_ip_address
+    if not dns:
+        raise UsageError("Failed to determine hostname of {0}.\n"
+                         "Please check that you provided --private-ips if "
+                         "necessary".format(instance))
     return dns