Step 1: Add addresses to your loopback; I will add 10.0.0.1, 10.0.0.2, 10.0.0.3, 10.0.0.4 and 10.0.0.5 to lo
[mpenning@tsunami ~]$ ip addr show lo
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
[mpenning@tsunami ~]$ sudo ip addr add 10.0.0.1/24 dev lo
[mpenning@tsunami ~]$ sudo ip addr add 10.0.0.2/24 dev lo
[mpenning@tsunami ~]$ sudo ip addr add 10.0.0.3/24 dev lo
[mpenning@tsunami ~]$ sudo ip addr add 10.0.0.4/24 dev lo
[mpenning@tsunami ~]$ sudo ip addr add 10.0.0.5/24 dev lo
[mpenning@tsunami ~]$ sudo ip addr show lo
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet 10.0.0.1/24 scope global lo
inet 10.0.0.2/24 scope global secondary lo
inet 10.0.0.3/24 scope global secondary lo
inet 10.0.0.4/24 scope global secondary lo
inet 10.0.0.5/24 scope global secondary lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
[mpenning@tsunami ~]$
Step 2: Increase max connections
Step 3: Start lots of connections...
from socket import socket, AF_INET, SOCK_STREAM
import select
class Server(object):
def __init__(self, addr="0.0.0.0", port=2525):
self.listen_addr = addr
self.listen_port = port
self.server = socket(AF_INET, SOCK_STREAM)
self.server.setblocking(0)
self.server.bind(self.socket_tuple)
self.server.listen(5)
def __repr__(self):
return "TCP Server listening on %s:%s" % (self.listen_addr,
self.listen_port)
@property
def socket_tuple(self):
return (self.listen_addr, self.listen_port)
def close(self):
self.server.close()
class Client(object):
def __init__(self, addr="0.0.0.0"):
self.listen_addr = addr
self.server_addr = None
self.server_port = None
self.client = socket(AF_INET, SOCK_STREAM)
self.client.setblocking(0)
finished = False
while not finished:
try:
### The point of my answer is here...
self.client.bind((addr,0)) # <- Bind to specific IP and rnd port
finished = True
except:
pass
def __repr__(self):
return "TCP Client %s->%s:%s" % (self.listen_addr,
self.server_addr, self.server_port)
def connect(self, socket_tuple=("0.0.0.0",0)):
self.server_addr = socket_tuple[0]
self.server_port = socket_tuple[1]
self.client.connect_ex(socket_tuple)
def close(self):
self.client.close()
READ_ONLY = select.POLLIN | select.POLLPRI | select.POLLHUP | select.POLLERR
clients = list()
servers = list()
for server_addr, port in [('10.0.0.1', 2525), ('10.0.0.2', 2526)]:
ss = Server(addr=server_addr, port=port)
servers.append(ss)
for client_addr in ['10.0.0.3', '10.0.0.4', '10.0.0.5']:
for ii in xrange(0, 25000):
cc = Client(addr=client_addr)
connection = cc.connect(socket_tuple=ss.socket_tuple)
finished = False
print " %s conns" % len(clients)
while not finished:
poller = select.poll()
poller.register(ss.server, READ_ONLY)
# Map file descriptors to socket objects...
fd_to_socket = {ss.server.fileno(): ss.server,}
events = poller.poll(1)
for fd, flag in events:
s = fd_to_socket[fd]
if flag & (select.POLLIN|select.POLLPRI):
if s is ss.server:
# server socket is ready to accept a connection
connection, client_address = s.accept()
connection.setblocking(0)
fd_to_socket[connection.fileno()] = connection
poller.register(connection, READ_ONLY)
finished = True
clients.append(cc)
print cc
print "Total Clients:", len(clients)
for cc in clients:
cc.close()
for ss in servers:
ss.close()
Adjust values above to your preferences... however, you should keep in mind that tuning a linux server to accept so many connections may be challenging... but at this point, that isn't the question you are asking...
