No reachability in the network with remote controller

Question

I am using the code below. Here I first add hc as host and after starting net I ran a simple switch in hc to make it a controller. The problem is there is no reachability in the network i.e. ping is not working. Could anyone please let me know what is causing this behaviour?

def myNetwork():
    # Create an instance of Mininet class i.e. the network with default values
    net = Mininet()

    info( '*** Adding controller\n' )
    #c0 = net.addController('c0')
    hc = net.addHost( 'hc', ip='127.0.0.1' )
    info( '*** Adding switches\n')
    s1 = net.addSwitch('s1')
    s5 = net.addSwitch('s5')
    s2 = net.addSwitch('s2')
    info( '*** Adding links\n')
    net.addLink(hc, s1)
    net.addLink(s1, s5, cls=TCLink)
    net.addLink(s5, s2, cls=TCLink)
   
    hosts = list()
    #  add all remaining hosts to s2
    info( '*** Adding hosts and Links\n')

    for i in range (1,11):
        name = 'h'+str(i)
        host = net.addHost(name)
        net.addLink( s2, host, cls=TCLink)
        hosts.append(host)
   
    info( '*** Starting network\n')
    net.start()
    hc.cmdPrint('ryu-manager ryu/simple_switch_13.py \
                --verbose 1> tmp/controller-ryu.log 2>&1 &')
    # Start the Mininet CLI to run commands
    CLI(net)
    # Stop the network
    net.stop()
  
if __name__ == '__main__':
    setLogLevel( 'info' )
    myNetwork()

Answer 1

A lot of parts are missing in the code, and the indentation was not correct.

hc is not needed to create your remote controller. You can use system("START CONTROLLER COMMAND") to run a remote controller like ryu (but I suggest to run the command outside your script). Than use the net.addController function using cls=RemoteController.

def myNetwork():
    # Create an instance of Mininet class i.e. the network with default values
    net = Mininet(controller=RemoteController)

    #info( '*** Adding controller\n' )
    c0 = net.addController('c0', cls=RemoteController)
    #hc = net.addHost( 'hc', ip='127.0.0.1' )
    info( '*** Adding switches\n')
    s1 = net.addSwitch('s1')
    s5 = net.addSwitch('s5')
    s2 = net.addSwitch('s2')
    info( '*** Adding links\n')
    #net.addLink(hc, s1)
    net.addLink(s1, s5, cls=TCLink)
    net.addLink(s5, s2, cls=TCLink)

    hosts = list()
    #  add all remaining hosts to s2
    info( '*** Adding hosts and Links\n')

    for i in range (1,11):
        name = 'h'+str(i)
        host = net.addHost(name)
        net.addLink( s2, host, cls=TCLink)
        hosts.append(host)

    info( '*** Starting network\n')
    net.start()
    #hc.cmdPrint('ryu-manager ryu/simple_switch_13.py \
    #            --verbose 1> tmp/controller-ryu.log 2>&1 &')
    # Start the Mininet CLI to run commands
    CLI(net)
    # Stop the network
    net.stop()

if __name__ == '__main__':
    from mininet.log import setLogLevel, info
    from mininet.net import Mininet
    from mininet.link import TCLink
    from mininet.cli import CLI
    from mininet.node import RemoteController

    setLogLevel( 'info' )
    myNetwork()