paramiko can be used to:

• SSH connect to a target system (this article)
• SCP files on a target system
• SFTP connect to a target system

At the bare minimum, the following is all that should be needed to make an SSH connection if the SSH server accepts basic authentication (username, password).

#!/usr/bin/python
import paramiko
ssh = paramiko.SSHClient()
result = ssh.connect("<hostname or IP address of target system>", 
                      username="<username>",
                      password="<password>")
print(result)
ssh.close()

Or like this, using an SSH key instead of a password, on a Linux system.

ssh.connect(server, username="john.doe", key_filename="/home/john.doe/.ssh/id_rsa.pub")

Or like this, using an SSH key instead of a password, on a Windows system.

ssh.connect(server, username="john.doe", key_filename=r"C:\Users\johndoe\.ssh\id_rsa")

If the SSH connection is successful, something like this should be printed.

<paramiko.client.SSHClient object at 0x7f1c69212f50>

Here is a more complete example which uses try / except / else to catch exceptions, ssh_exec to run a command after creating the SSH connection, and ssh.close to close the SSH connection.

#!/usr/bin/python3
import paramiko
def ssh_connect(server, user, pw):
  ssh = paramiko.SSHClient()
  ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
  try:
    ssh.connect(server, 
                username=user, 
                key_filename"/home/john.doe/.ssh/id_rsa.pub",
                timeout=10)
  except Exception as exception:
    return f"ssh.connect raised the following exception: {exception}"
  else:
    return ssh
def ssh_exec(ssh, command):
  try:
    ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command(command)
  except Exception as exception:
    return f"ssh.exec_command raised the following exception: {exception}"
  else:
    return ssh_stdout.read(), ssh_stderr.read(), ssh_stdout.channel.recv_exit_status()
ssh = ssh_connect("server1.example.com", "john.doe", "itsasecret")
stdout, stderr, return_code = ssh_exec(ssh, "the command you want to issue on the target system")
print(f"stdout      = {stdout}")
print(f"stderr      = {stderr}")
print(f"return code = {return_code}")
ssh.close()

Be aware that paramiko may append unwanted events to your log file. If you are using logging, you can set paramiko to only log events at a certain log level, such as WARNING.

logging.getLogger("paramiko").setLevel(logging.WARNING)

With Python 2, the output should be returned as a string, but with Python 3 the stdout and stderr is returned as bytes, so it's a good idea to include decode to convert bytes to string for Python 3.

def ssh_exec(ssh, command):
  try:
    ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command(command)
  except Exception as e:
    return f"ssh.exec_command raised the following exception: {exception}"
  else:
    return ssh_stdout.read().decode('utf-8'), ssh_stderr.read().decode('utf-8'), ssh_stdout.channel.recv_exit_status()