No default OpenFlow controller found for default switch!

[tuxx42]

There doesn't seem to be support for spawning the openvswitch-controller, so the setup defaults back to bridge mode.

root@a5e1cbd71ce8:~# mn
*** No default OpenFlow controller found for default switch!
*** Falling back to OVS Bridge
*** Error setting resource limits. Mininet's performance may be affected.
*** Creating network
*** Adding controller
*** Adding hosts:
h1 h2 
*** Adding switches:
s1 
*** Adding links:
(h1, s1) (h2, s1) 
*** Configuring hosts
h1 h2 
*** Starting controller

*** Starting 1 switches
s1 ...
*** Starting CLI:
mininet> dump
<Host h1: h1-eth0:10.0.0.1 pid=87> 
<Host h2: h2-eth0:10.0.0.2 pid=89> 
<OVSBridge s1: lo:127.0.0.1,s1-eth1:None,s1-eth2:None pid=94> 

[iwaseyusuke]

@tuxx42 Thank you for using this Docker image!

Mininet uses ovs-testcontroller as the default controller if you omit --controller option, but this image does not contain ovs-testcontroller. This image suppose to use the "remote" controller with --controller remote[,ip=<ip>][,port=<port>] option in order to test your own OpenFlow controller implementation (e.g. Ryu, OpenDaylight,...) on other containers or Docker host.

[iwaseyusuke]

Also, if you need to use OVS with the bridge mode, you can use --switch ovsbr option.

root@e8823147f98e:~# mn --switch ovsbr
*** Error setting resource limits. Mininet's performance may be affected.
*** Creating network
*** Adding controller
*** Adding hosts:
h1 h2 
*** Adding switches:
s1 
*** Adding links:
(h1, s1) (h2, s1) 
*** Configuring hosts
h1 h2 
*** Starting controller

*** Starting 1 switches
s1 ...
*** Starting CLI:
mininet> 

[tuxx42]

okay, i was looking for a self contained solution with a controller... but that makes sense i guess. thanks for clarifying.. feel free to close 👍

[iwaseyusuke]

On my another repo docker-ryu-mininet, Ryu controller is composed within the same container by using this image as the base image. I hope it should be helpful for you.

[Thaodtt12]

excuse me, please explain for me about that. When I setup mininet I see it, too. But I dont understand so I cant solve my problem. thanks for reading

[iwaseyusuke]

@inseo3003 Hi,
As explain on #1 (comment), I wrote this image for developing Ryu SDN Controller. So when I using this image, I always specify —remote-controller option, then the default controller should not be required.
If you need to run Mininet with the default controller, please install ovs-testcontroller after starting this container.

[iwaseyusuke]

The commit 32aa417 includes ovs-testcontroller. This problem should be solved with the latest image.

[akrami6194]

hello
How to fix the message "No default OpenFlow controller found for default switch" in mininet

[iwaseyusuke]

Hi @akrami6194
Because it is the behavior of Mininet, I don’t know the details, but iI don’t think the message "No default OpenFlow controller found for default switch!" is always a kind of error.

On the Mininet's repo, "mn" command seems to output this message when you run "mn" without any "--controller" option.

https://github.com/mininet/mininet/blob/57294d013e780cccc6b4b9af151906b382c4d8a7/bin/mn#L342-L356

  --controller=CONTROLLER
                        default|none|nox|ovsc|ref|remote|ryu[,param=value...]
                        ovsc=OVSController none=NullController
                        remote=RemoteController default=DefaultController
                        nox=NOX ryu=Ryu ref=Controller