Fabric example for SSH keyfile connection

fabfile.py

from fabric.api import *

env.hosts = ['host.name.com']
env.user = 'user'
env.key_filename = '/path/to/keyfile.pem'

def local_uname():
    local('uname -a')

def remote_uname():
    run('uname -a')

Thanks for the gist. You can also accomplish this via an ssh-config. I've forked your gist to show how.

How to gen /path/to/keyfile.pem ?

Despite defining the env.hosts = ['host-name.fqdn-format']. Following input is asked during execution:
No hosts found. Please specify (single) host string for connection: