python spark_ec2.py  --region="us-west-1" --key-pair=test
     --identity-file=test.pem --instance-type="t2.micro"
     --slaves 1 launch spark-cluster

python spark_ec2.py  --region="us-west-1" --key-pair=test --identity-file=test.pem login spark-cluster

import os
from stat import *
oct(os.stat("test.pem")[ST_MODE])