import paramiko
 
hostname = '192.168.1.1'
port = 22
username = 'foo'
#pkey_file = '/home/foo/.ssh/id_rsa'
pkey_file = r'C:\Users\Administrator\.ssh\id_rsa'
 
if __name__ == "__main__":
    key = paramiko.RSAKey.from_private_key_file(pkey_file)
    s = paramiko.SSHClient()
    s.load_system_host_keys()
    #s.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    s.connect(hostname,port,username,pkey=key)
    stdin, stdout, stderr = s.exec_command('pwd')
    print stdout.read()
    s.close()