Create a lot of sshd host for testing, based on mininet

mininet_sshd.py

#!/usr/bin/python
import ipaddress
import argparse

from mininet.topo import Topo
from mininet.nodelib import LinuxBridge
from mininet.net import Mininet
from mininet.cli import CLI
from mininet.util import waitListening

class SSHdTopo(Topo):
    def __init__(self, bridge_name, num_hosts=4):
        Topo.__init__(self)
        hosts = [self.addHost('h%d' % i) for i in xrange(num_hosts)]
        br = self.addSwitch(bridge_name, cls=LinuxBridge)
        for host in hosts:
            self.addLink(host, br)

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='start ip and bridge name required.')
    parser.add_argument('ip', help='Begining ip')
    parser.add_argument('-n', '--num-of-hosts', dest='num_of_hosts', type=int, metavar='NUM-OF-HOSTS', default=100,
                        help='Amount of hosts to run, default is 100')
    parser.add_argument('-b', '--bridge', dest='bridge_name', default='br0',
                        help='Linux bridge name, default is br0')
    args = parser.parse_args()

    topology = Mininet(SSHdTopo(args.bridge_name, args.num_of_hosts))
    ip = ipaddress.ip_address(unicode(args.ip))
    prefix = '16'
    for host in topology.hosts:
        host.setIP(str(ip) + '/' + prefix)
        ip = ip + 1
        host.cmd('/usr/sbin/sshd -D &')
    br = topology[args.bridge_name]
    br.start(topology['c0'])
    br.cmd('brctl addif %s eth0' % args.bridge_name)
    print "*** Enviroment ready, Type 'exit' or control-D to shut down network"
    CLI(topology)
    for host in topology.hosts:
        host.cmd('kill %/usr/sbin/sshd')