2014년 11월 11일 화요일

Setting up OpenDaylight Hydrogen VM - Ubuntu 14.04

On Wednesday and Thursday (Nov. 5 & 6) last week, I participated in my first Hackathon -- Cisco Codefest 2014 -- which was held at the POSCO Engineering and Construction Building main hall 4F in Songdo, South Korea. The track my team chose for the competition was OpenDaylight, a Software Defined Networking (SDN) framework led by the Linux Foundation, Redhat, Cisco, and other partners. This framework enables network devices to be virtualized (NFV - Network Function Virtualization) which opens up the possibility of regular PC's with multiple PCI network cards being able to act as cheap switches, for example, among other possibilities.

Although this contest was a coding competition, our team spent a lot of time doing Linux sysadmin work to get the OpenDaylight VM's into a usable state. We also spent a significant chunk of time learning how to use mininet, the network simulator bundled with the OpenDaylight VM, and setting up network visualization (DLUX - Daylight User Interface) provided by Karaf from the ODL Helium container. This post will walk you through the process of customizing the Ubuntu 14.04 VM available for download from the ODL Hydrogen downloads page (you can navigate here from the main OpenDaylight Downloads page).


Virtualbox Settings for Ubuntu 14.04 VM

As of 2014-11-11 the download link for the Ubuntu 14.04 VM appears as odl-test-desktop-3.ova, but once you actually import it into Virtualbox, the name of the VM appears as odl-test-desktop-2, which is the name of the Ubuntu 13.04 VM available at the second download link in the middle. Here's a screenshot of the page:




I thought I had downloaded the wrong VM, but after verifying with uname -a that the guest OS was running kernel 3.13, I was sure I was running Ubuntu 14.04 (instead of 13.04, the version in the other two VM's available for download). Note that all the Ubuntu ODL images are 64-bit, so if you're running a 32-bit version of say, Windows 7 (or Linux, for that matter), you will not be able to run the VM's even if you have Virtualbox installed (my Codefest teammate actually went out and bought a new laptop because his Core i5 with just 2GB RAM just wasn't up to the task of running the heavy Ubuntu 14.04 VM's).

First, after importing the VM you should first tweak some settings for speed. The download page does mention  "disable 3D acceleration otherwise left menu may not show," (the Unity bar on the left-hand margin) but in my case, leaving 3D acceleration on in the VM display settings also caused problems with my host machine display, making me unable to minimize the VM full-screen window. So you definitely want to make sure that 3D acceleration box is not checked in the following window from the Virtualbox Manager:


Second, from the "System" tab above, you should reduce the number of CPU cores allocated to the VM from 4(!) to something more manageable for your system. Likewise with memory; the memory initially allocated to the VM is 4096MB (4 GB), but I found that for simple topologies 2 CPU cores and 2GB works fine.

Third, from the "Network" tab above, make Adapter 1 attached to "Bridged Adapter" and choose the name of your host machine's network interface. Adapter 1 will provide your VM with Internet access from your host and will also give the VM an IP within the same subnet as your host making ssh possible. You should also enable Adapter 2 as a "Host-only" interface that you can use exclusively for a mininet network. If you do not have any host-only interfaces enabled, click "File" -> "Preferences" -> "Network" from the Virtualbox Manager and select the "Host-only Networks" tab. Click the '+' icon to add one interface (which appears as vboxnet0 in Linux hosts).



Fourth, the VM will not be able to go full screen until you intstall the Virtualbox Guest Additions into the guest OS. Refer to this previous post on my blog for instructions on how to do this in a Linux VM. It would be nice if the people at the ODL foundation actually installed the Virtualbox Guest Additions into the Ubuntu 14.04 VM before exporting it as an .ova file...

Setting up the Application Environment

Fifth, seriously consider installing a lighter Desktop Environment (DE) like XFCE or LXDE. Unity with compiz is installed by default as the Ubuntu 14.04 DE, but its 3D bling, compositing, drop shadows, etc. are superfluous to the job of running network simulations for SDN. In fact, once you launch Karaf (from ODL Helium) and mininet you will find that even powerful systems will lag (my teammate's new machine, a brand-new Core i7 laptop with 256GB SSD and 8GB of RAM ran sluggishly with Unity enabled while running mininet et al). If you run top within the VM while using Unity, it is not uncommon to see compiz taking up 20%+ of CPU.

Don't worry -- installing a new DE does not require the removal of Unity and compiz! Once the new DE is installed through apt-get, you can select what DE to use from the login screen. To install either XFCE or LXDE for Ubuntu, enter one of the following:

sudo apt-get install --no-install-recommends xubuntu-desktop

sudo apt-get install --no-install-recommends lubuntu-desktop

It would also be a good idea to turn off automatic updates... this is a VM, after all, so you should only do point updates for packages that really need it.

Sixth, set up Wireshark. Although it is pre-installed in the VM, running it as the regular user mininet will not allow you to listen to network traffic on any of the network interfaces. That doesn't mean you should run Wireshark as root, however (doing so is a security risk). Instead, run dpkg-reconfigure wireshark-common from the CLI. This will enable regular users to listen on network interfaces as long as they are members of the newly-created user group wireshark. To add user mininet to group wireshark:

sudo usermod -a -G wireshark mininet

For changes to take effect, you must log out and log in once again.

Seventh, install Karaf from ODL Helium. From the main ODL download page, click the link for either the zip or tar archive and extract the files into a folder in the ODL Hydrogen VM. Once you have extracted the files, navigate to the folder and enter the bin directory and invoke karaf as follows:

mininet@mininet-vm:~/distribution-karaf-0.2.0-Helium/bin\> ./karaf

karaf will work with any JVM running Java 1.7 or higher. Fortunately, the Ubuntu VM comes with OpenJDK 7 runtime already installed. Once karaf is installed and running, from the karaf command prompt enter the following to install packages necessary for DLUX:

opendaylight-user@root>feature:install odl-restconf odl-l2switch-switch odl-mdsal-apidocs odl-dlux-core

Now when you create a network in mininet and generate traffic between hosts, you will be able to see the topology by opening a browser within the VM and navigating to localhost:8181/dlux/index.html, logging in with admin:admin, and clicking on "Topology" from the left-hand menu within the browser page body. (Note: If you launch mininet with default settings, it will try to create a network controller on localhost:6633, but this conflicts with the controller created by karaf. To avoid this conflict, you need to specify the IP for a remote controller and a port that doesn't conflict with 6633. In our case, we will use port 6653.)


Example of mininet and karaf in action with topology visualization

Open two terminals within the VM and start karaf in one of them. Once karaf is fully loaded (this can take up to 60 seconds), we will launch mininet with a remote controller residing on the host-only IP for our VM, 192.168.56.101:

mininet@mininet-vm:~\> sudo mn --mac --switch=ovsk,protocols=OpenFlow13 --controller=remote,ip=192.168.56.101,port=6653 --topo=tree,2



We have created a tree topology 2 levels deep (switch 1 is the root node, switches 2 and 3 branch from s1) using an open virtual switch with openflow 1.3

Note that we have changed the controller port to 6653 so that it will not conflict with the karaf controller. Within the mininet command environment, we invoked pingall -c 1 (ping all hosts 1 time) to generate network traffic (if there is no traffic, DLUX will not show any flows). Now navigating to localhost:8181 and navigating to Topology should show the following:


Now your Ubuntu 14.04 VM for ODL Hydrogen should be ready for you to experiment with SDN!