os-ken

4.1.1 verified Mon Apr 27 auth: no python

A component-based software defined networking framework for OpenStack, currently at version 4.1.1. It is actively maintained with a focus on SDN controller development.

pip install os-ken

Common errors

error ModuleNotFoundError: No module named 'ryu' ↓

cause Code written for Ryu imported under 'ryu' instead of 'os_ken'.

fix

Replace import ryu with import os_ken.

error ImportError: cannot import name 'RyuApp' from 'os_ken.base.app_manager' ↓

cause Base class renamed from RyuApp to OSKenApp.

fix

Use 'from os_ken.base.app_manager import OSKenApp'.

error RuntimeError: Python version <3.10 not supported ↓

cause os-ken 4.x requires Python 3.10+.

fix

Upgrade Python to 3.10 or later, or install os-ken 3.x with pip install os-ken==3.6.0.

Warnings

breaking Python 3.10+ required; os-ken 4.x drops Python 3.8/3.9 support. ↓

fix Use Python 3.10 or later, or pin to os-ken 3.x if older Python needed.

breaking Renamed base app class from RyuApp to OSKenApp; all Ryu imports broken. ↓

fix Replace 'ryu' with 'os_ken' in imports and RyuApp with OSKenApp.

gotcha os-ken uses same OF-Config and OpenFlow libraries as Ryu but with different module paths. ↓

fix Always import from os_ken not ryu; check os_ken documentation for exact paths.

deprecated Some Ryu extension modules (e.g., ryu.topology) may not be fully ported; use os_ken.topology. ↓

fix Check if the extension is available under os_ken; fallback to lower version if needed.

Imports

OFPHandler

wrong

from ryu.base.app_manager import OFPHandler

correct

from os_ken.base.app_manager import OFPHandler

os-ken is a fork of Ryu; all imports use os_ken prefix.

Controller

wrong

from ryu.cmd.manager import Controller

correct

from os_ken.cmd.manager import Controller

Common mistake due to Ryu legacy.

add_flow

wrong

from ryu.ofproto.ofproto_v1_3 import OFPFlowMod

correct

from os_ken.ofproto.ofproto_v1_3 import OFPFlowMod

Module path changed from ryu to os_ken.

NetworkApp

wrong

from ryu.base.app_manager import RyuApp

correct

from os_ken.base.app_manager import OSKenApp

Base app class renamed; use OSKenApp instead.

Quickstart

Simple SDN controller app that prints switch ID on connection.

from os_ken.base.app_manager import OSKenApp
from os_ken.controller.handler import set_ev_cls
from os_ken.ofproto.ofproto_v1_3 import OFPFlowMod

class SimpleSwitch(OSKenApp):
    @set_ev_cls(OFPFlowMod)
    def switch_features_handler(self, ev):
        msg = ev.msg
        print(f"Switch {msg.datapath.id} connected")

if __name__ == '__main__':
    from os_ken.cmd.manager import Controller
    c = Controller()
    c.start()