Spark EC2 SSH connection error SSH return code 255

Question

Every time I try to start a Spark cluster on AWS via the Spark ec2/spark_ec2.py file I get an SSH connection error that eventually gets resolved but wastes a lot of time.

Before you mark this as a duplicate I'm aware there quite a few similar questions asked but there are two key distinctions: a) my connection always completes (eventually) and I end up with a healthy Spark cluster and b) the "answers" for the other questions are generally centered around previous Spark versions (e.g., 1.2, 1.3, etc.). I have always experienced this issue going back 12 months ago w/1.3 through today with 1.6.1.

Thanks in advance!

Terminal Output:

Launched master in us-east-1e, regid = r-a1b2c3d4
Waiting for AWS to propagate instance metadata...
Waiting for cluster to enter 'ssh-ready' state...........

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.

Warning: SSH connection error. (This could be temporary.)
Host: ec2-xx-xx-xx-xxx.compute-1.amazonaws.com
SSH return code: 255
SSH output: ssh: connect to host ec2-xx-xx-xx-xxx.compute-1.amazonaws.com port 22: Connection refused

.
Cluster is now in 'ssh-ready' state. Waited 833 seconds.
Generating cluster's SSH key on master...

Answer 1

Please check if your security group in EC2 has ssh port(22) open.

Answer 2

Check this, you must enable inbound ssh traffic