diff --git a/ec2/spark_ec2.py b/ec2/spark_ec2.py
index abab209a05ba0..acbb61c66cada 100755
--- a/ec2/spark_ec2.py
+++ b/ec2/spark_ec2.py
@@ -896,6 +896,7 @@ def stringify_command(parts):
 
 def ssh_args(opts):
     parts = ['-o', 'StrictHostKeyChecking=no']
+    parts += ['-o', 'UserKnownHostsFile=/dev/null']
     if opts.identity_file is not None:
         parts += ['-i', opts.identity_file]
     return parts