SSH - Python with paramiko issue

Question

I've been trying to get this to work but keep getting the same errors. I've tried the fqdn and ip of the host. I've tried to pass it with credentials and without. I've looked at the lines indicated in the error message. Searched google, but cannot figure out why this is not working:

import paramiko
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect('host', username='loginname')
stdin, stdout, stderr = ssh.exec_command("pwd")
stdout.readlines()

Error:

Traceback (most recent call last):
  File "audit.py", line 7, in <module>
    ssh.connect('host', username='loginname')
  File "/usr/lib/python2.6/site-packages/paramiko/client.py", line 338, in connect
    self._auth(username, password, pkey, key_filenames, allow_agent, look_for_keys)
  File "/usr/lib/python2.6/site-packages/paramiko/client.py", line 520, in _auth
    raise SSHException('No authentication methods available')

• I am able to connect to the host with no issue via ssh.
• ssh version: OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010
• To note: I'm trying to create a way of running a series of commands on several remote servers. I'm using sys import argv to run the script such as python audit.py host1 host2 host3, and then the script will run through the audit for those particular hosts. I've already created a bash script that accomplishes this but I wanted a better way of doing it via Python.

Answer 1

You should provide either a password or a private key (or both), otherwise the SSH client does not know how to authenticate with the login data.

Here is my code example for your reference.

#!/usr/bin/python

from StringIO import StringIO
import paramiko 

class SshClient:
    "A wrapper of paramiko.SSHClient"
    TIMEOUT = 4

    def __init__(self, host, port, username, password, key=None, passphrase=None):
        self.username = username
        self.password = password
        self.client = paramiko.SSHClient()
        self.client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        if key is not None:
            key = paramiko.RSAKey.from_private_key(StringIO(key), password=passphrase)
        self.client.connect(host, port, username=username, password=password, pkey=key, timeout=self.TIMEOUT)

    def close(self):
        if self.client is not None:
            self.client.close()
            self.client = None

    def execute(self, command, sudo=False):
        feed_password = False
        if sudo and self.username != "root":
            command = "sudo -S -p '' %s" % command
            feed_password = self.password is not None and len(self.password) > 0
        stdin, stdout, stderr = self.client.exec_command(command)
        if feed_password:
            stdin.write(self.password + "\n")
            stdin.flush()
        return {'out': stdout.readlines(), 
                'err': stderr.readlines(),
                'retval': stdout.channel.recv_exit_status()}

if __name__ == "__main__":
    client = SshClient(host='host', port=22, username='username', password='password') 
    try:
       ret = client.execute('dmesg', sudo=True)
       print "  ".join(ret["out"]), "  E ".join(ret["err"]), ret["retval"]
    finally:
      client.close()