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Mininet is a container orchestration system for network emulation. With Mininet and onos.py, you can easily start up an ONOS cluster in a single VM or server. This is usually the most convenient way to create an ONOS development environment on your laptop.

Getting Mininet

In order to use onos.py, you need Mininet. It's easy to install Mininet in an Ubuntu VM or server using apt-get:

apt-get install mininet

or from source:

git clone http://github.com/mininet/mininet
mininet/util/install.sh -nv

You can also download a pre-built Mininet VM.

Creating a virtual ONOS network using onos.py and Mininet

If you are using Mininet in a VM or on a physical server, it is easy to use onos.py to start up a complete emulated ONOS network, including ONOS cluster, modeled control network, and data network.

This simplifies development on a laptop, because you can run a single development VM (or no VM at all if you are running on a Linux machine!) Moreover, it is more efficient than a multi-VM setup because the entire emulated network lives in a single VM and shares a single Linux kernel.

Chances are you're already using Mininet, so it's nice to be able to start an ONOS cluster using Mininet itself without installing or configuring additional software.

 

Note: This is work in progress - if you wish to try it now, you will need to get onos.py from the following patch: https://gerrit.onosproject.org/#/c/9143/


Running ONOS and Mininet

First, make sure that you have built ONOS in your Mininet VM or server using buck:

cd ~/onos
buck build onos

Next, use Mininet and onos.py to start up a virtual ONOS cluster and data network:

cd ~/onos/tools/dev/mininet
sudo mn --custom onos.py --controller onos,3 --topo torus,4,4

You should see a bunch of output showing the startup of the control network and the data network.

After ONOS starts up and the switches connect, you should see the mininet CLI prompt:

mininet>

At this point, you can enter mininet commands like pingall (all-to-all ping test) and help (find out about Mininet CLI commands.)

To exit Mininet, use the exit command or press control-D.

If things don't start up correctly, look carefully at any error messages or exceptions which may have been generated - usually they give you important information which will enable you to figure out what is going wrong and to fix the issue. Also check out the troubleshooting section below.

 

Questions and Answers

What do those mn command line options do?

--custom onos.py: uses onos.py to extend Mininet with new controller and switch types

--controller onos,3: tells Mininet to start up an ONOS controller cluster with 3 ONOS nodes

--topo torus,4,4: tells Mininet to use a 4x4 torus topology for the data network

What software switch does this use?

By default, it uses Open vSwitch. onos.py replaces the default switch with a new switch class called ONOSOVSSwitch or --switch onosovs. This switch class knows how to connect to an ONOS cluster with multiple IP addresses.

How can I use the user switch (or CPqD switch if I have it installed?)

In order to select the user switch (either Stanford reference switch or CPqD switch, depending on which one you have installed), you can use --switch onosuser.

How can I get more information on Mininet, the mn command, writing Mininet scripts, etc.?

For more information on Mininet, please check out http://docs.mininet.org

How can I specify the apps for ONOS to load?

For now, try using ONOS_APPS or connecting to the karaf console and using ONOS CLI commands. As root:

ONOS_APPS=drivers,openflow,fwd,proxyarp,mobility mn --custom onos.py --controller onos,3 --topo tree,3,3

or (with sudo):

sudo env ONOS_APPS=drivers,openflow,fwd,proxyarp,mobility mn --custom onos.py --controller onos,3 --topo tree,3,3

or

ONOS_APPS=drivers,openflow,fwd,proxyarp,mobility sudo -E mn --custom onos.py --controller onos,3 --topo tree,3,3
 

Note that sudo clears environment variables by default, but the ONOS_APPS environment variable must be set in order for mn to read it.

In the future, there should be an option to --controller onos and/or ONOSCluster().

How are IP addresses of the ONOS cluster specified?

ONOSCluster takes an ipBase option; default is 192.168.123.0/24

How can I connect to the ONOS console?

Make sure karaf's bin directory is in your path, then:

client -h 192.168.123.1   # or the address of the ONOS node you wish to connect to  

How can I connect to the karaf console using ssh?

ssh -p 8101 karaf@192.168.123.1

In this example, 8101 is the karaf port, and 192.168.123.1 is the IP address of onos1.

How can I connect to the ONOS GUI if ONOS is running in a Mininet host inside a VM?

One way is to use ssh port forwarding, e.g.

ssh -L 8081:192.168.123.1:8081 mininet-vm

from your laptop. This forwards port 8081 on 192.168.123.1 in mininet-vm to port 8081 on your laptop. (8081 is the default ONOS GUI port, and 192.168.123.1 is the default IP address for onos1.)

Then open up http://localhost:8101/onos/ui/ in your browser.

Another way is to run a browser such as Firefox or Chromium in your development VM or server.

firefox &

We hope to make it easier and more automatic in the future.

How can I look at the karaf log file for (which usually contains ONOS's log messages) for onos1?

tail -f /tmp/onos1/log

How can I look at the onos-service log file (which usually doesn't contain much of anything unless there are errors starting karaf) for onos1? 

tail -f /tmp/onos1/onos.log

Can I ssh into the ONOS cluster?

Not directly with this version of onos.py, since the nodes are not running ssh by default. However, if you have a Mininet source tree, you can attach to it using mininet/util/m:

~/mininet/util/mn 192.168.123.1

Can I use the onos-* scripts from tools/test/bin with this environment?

Not currently, but you should not need to use them for the most part.

Troubleshooting

onos.py doesn't work - what should I do?

Here are some things you can try:

  • Look at the log file(s) and make sure no errors are occurring: more /tmp/onos1/log; more /tmp/onos1/onos.log
  • Look at the output from running mn or onos.py and carefully examine and try to understand any error or exception messages - usually they will tell you what is going wrong
  • Reset your environment using: sudo pkill -f  karaf.jar; sudo mn -c
  • Make sure you have built onos: cd ~/onos; buck build onos 
  • Make sure you can run Mininet: sudo mn --test pingall 

Mininet doesn't work - what should I do?

Make sure that the following command works:

sudo mnexec -n ifconfig -a

It should show a single loopback interface and no other interfaces. If this command doesn't work as expected, then Mininet will not work. If you have installed Mininet using apt-get, or from source on Ubuntu, Mininet should work correctly. However, you should make sure you don't have multiple or older versions of Mininet installed which might not work correctly with onos.py.

Once you've verified that mnexec works, you can try a sanity check for mn:

sudo mn --test pingall

This should complete without errors.

 

 

 

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