Mininet flow analytics describes how to use the
sflow.py helper script that ships with the
sFlow-RT analytics engine to enable sFlow telemetry, e.g.
sudo mn --custom sflow-rt/extras/sflow.py --link tc,bw=10 \
--topo tree,depth=2,fanout=2
Mininet, ONOS, and segment routing provides an example using a
Custom Topology, e.g.
sudo env ONOS=10.0.0.73 mn --custom sr.py,sflow-rt/extras/sflow.py \
--link tc,bw=10 --topo=sr '--controller=remote,ip=$ONOS,port=6653'
This article describes how to incorporate sFlow monitoring in a fully custom Mininet script. Consider the following
simpletest.py script based on
Working with Mininet:
#!/usr/bin/python
from mininet.topo import Topo
from mininet.net import Mininet
from mininet.util import dumpNodeConnections
from mininet.log import setLogLevel
class SingleSwitchTopo(Topo):
"Single switch connected to n hosts."
def build(self, n=2):
switch = self.addSwitch('s1')
# Python's range(N) generates 0..N-1
for h in range(n):
host = self.addHost('h%s' % (h + 1))
self.addLink(host, switch)
def simpleTest():
"Create and test a simple network"
topo = SingleSwitchTopo(n=4)
net = Mininet(topo)
net.start()
print "Dumping host connections"
dumpNodeConnections(net.hosts)
print "Testing bandwidth between h1 and h4"
h1, h4 = net.get( 'h1', 'h4' )
net.iperf( (h1, h4) )
net.stop()
if __name__ == '__main__':
# Tell mininet to print useful information
setLogLevel('info')
simpleTest()
Add the
highlighted lines to incorporate sFlow telemetry:
#!/usr/bin/python
from mininet.topo import Topo
from mininet.net import Mininet
from mininet.util import dumpNodeConnections
from mininet.log import setLogLevel
from mininet.util import customClass
from mininet.link import TCLink
# Compile and run sFlow helper script
# - configures sFlow on OVS
# - posts topology to sFlow-RT
execfile('sflow-rt/extras/sflow.py')
# Rate limit links to 10Mbps
link = customClass({'tc':TCLink}, 'tc,bw=10')
class SingleSwitchTopo(Topo):
"Single switch connected to n hosts."
def build(self, n=2):
switch = self.addSwitch('s1')
# Python's range(N) generates 0..N-1
for h in range(n):
host = self.addHost('h%s' % (h + 1))
self.addLink(host, switch)
def simpleTest():
"Create and test a simple network"
topo = SingleSwitchTopo(n=4)
net = Mininet(topo,link=link)
net.start()
print "Dumping host connections"
dumpNodeConnections(net.hosts)
print "Testing bandwidth between h1 and h4"
h1, h4 = net.get( 'h1', 'h4' )
net.iperf( (h1, h4) )
net.stop()
if __name__ == '__main__':
# Tell mininet to print useful information
setLogLevel('info')
simpleTest()
When running the script the
highlighted output confirms that sFlow has been enabled and the topology has been posted to sFlow-RT:
pp@mininet:~$ sudo ./simpletest.py
*** Creating network
*** Adding controller
*** Adding hosts:
h1 h2 h3 h4
*** Adding switches:
s1
*** Adding links:
(10.00Mbit) (10.00Mbit) (h1, s1) (10.00Mbit) (10.00Mbit) (h2, s1) (10.00Mbit) (10.00Mbit) (h3, s1) (10.00Mbit) (10.00Mbit) (h4, s1)
*** Configuring hosts
h1 h2 h3 h4
*** Starting controller
c0
*** Starting 1 switches
s1 ...(10.00Mbit) (10.00Mbit) (10.00Mbit) (10.00Mbit)
*** Enabling sFlow:
s1
*** Sending topology
Dumping host connections
h1 h1-eth0:s1-eth1
h2 h2-eth0:s1-eth2
h3 h3-eth0:s1-eth3
h4 h4-eth0:s1-eth4
Testing bandwidth between h1 and h4
*** Iperf: testing TCP bandwidth between h1 and h4
*** Results: ['6.32 Mbits/sec', '6.55 Mbits/sec']
*** Stopping 1 controllers
c0
*** Stopping 4 links
....
*** Stopping 1 switches
s1
*** Stopping 4 hosts
h1 h2 h3 h4
*** Done
Mininet dashboard and
Mininet weathermap describe the sFlow-RT Mininet Dashboard application shown at the top of this article. The tool provides a real-time visualization of traffic flowing over the Mininet network.
Writing Applications describes how to develop custom analytics applications for sFlow-RT.
