paramiko_agent_test.py

import logging
from socket import gaierror, error as socket_error

from paramiko import (
    SSHClient, MissingHostKeyPolicy, SSHException, AuthenticationException
)

from inventory import ALL


logger = logging.getLogger('paramiko-test')
logging.basicConfig(level=logging.CRITICAL)
logger.setLevel(logging.DEBUG)

connected_hosts = {}
count = 0

for hostname, data in ALL:
    try:
        client = SSHClient()
        client.set_missing_host_key_policy(MissingHostKeyPolicy())
        client.connect(
            hostname,
            username='ubuntu', port=22, timeout=5,
            # Add explcit pkey=RSAKey object here and it works
        )

        count += 1
        logger.info(u'\t#{0}\t{1} connected'.format(count, hostname))

        connected_hosts[hostname] = client

    except AuthenticationException as e:
        logger.error(u'Auth error on: {0}, {1}'.format(hostname, e))

    except SSHException as e:
        logger.error(u'SSH error on: {0}, {1}'.format(hostname, e))

    except gaierror:
        logger.error(u'Could not resolve: {0}'.format(hostname))

    except socket_error as e:
        logger.error(u'Could not connect: {0}:{1}, {2}'.format(
            hostname, 22, e
        ))


import ipdb
ipdb.set_trace()

On OSX: after 250 hosts, connections fail with ssh-agent: failed unless the private key is added manually.