Send commands over ssh to AWS EC2 instances

Execute "df -H" command in all instances with highway as role.

The following environment variables have to be properly set:

• AWS_ACCESS_KEY_ID
• AWS_SECRET_ACCESS_KEY
• AWS_REGION

To use environment variables, do the following:

$ export AWS_ACCESS_KEY_ID=<access_key>
$ export AWS_SECRET_ACCESS_KEY=<secret_key>
$ export AWS_REGION=<region>

Distributed under MIT license. See LICENSE for more information.