Part1 - OPENVSWICH - Creating and Submitting Openvswitch Extension To Microcore Upstream

In May 2011, I read a request for installation Openvswitch on Qemu image. I started to play with Openvswitch and finally became addictive to this project. I realized how powerful  can be Openvswitch, offering many features listed here.  Spending my free time playing with Microcore and Openvswitch after several days I was able to create Microcore Qemu image with 8021q support  and install Openvswitch on top of it.

In this tutorial I would like to show how to create Openvswitch extension and make it ready for submit to the Microcore/Tinycore upstream.  I chose Microcore Linux, because I am familiar with this minimal Linux distribution and the Microcore is incredibly  small. Unless there is not the newer version than Openvswitch 1.2.2 you don’t have to create an Openvswitch extension since my extension has been added to  Microcore repository.

The following steps describe installation Openvswitch on Qemu image with pre-installed Microcore Linux.

If you don’t want to install openvswitch by yourself, you can download my own Openvswitch 1.2.2 /Microcore 4.0 Qemu mage.

http://www.4shared.com/file/6m9U-Gzd/linux-microcore-40-openvswitch.html

I also created three labs using Openvswitch. I tested how can Openvswitch works with VLANs, 802.1q trunk ports,  if it was capable of creating L3 VLAN interfaces and Inter VLAN routing was working.  Labs are available here:

1. Start Qemu Microcore image

Assuming your Microcore Qemu image with console support has been created and supports 8021q VLAN tagging, start the image:

qemu-kvm /home/brezular/linux-microcore-4.0.img -m 512

2. Download Openvswitch and Extract it

wget http://openvswitch.org/releases/openvswitch-1.2.2.tar.gz

tar zxvf ./openvswitch-1.2.2.tar.gz

cd ./openvswitch-1.2.2

3. Install Necessary Dependences for Openvswitch Compilation

tce-load -w -i compiletc.tcz python.tcz perl5.tcz openssh.tcz openssl-0.9.8.tcz openssl-0.9.8-dev.tcz tunctl.tcz linux-headers-3.0.3-tinycore.tcz bridge-utils.tcz

To run the ovsdmonitor tool, the machine must also have the following installed software:

tce-load -w -i python_twisted-2.7.tcz python-simplejson.tcz python_zope.interface-2.7 pyqt.tcz

Note:  The kernel source will be saved in /lib/modules/`uname -r`/build

It is recommended to check the list of necessary applications here:

4. BusyBox Story

BusyBox 1.18.3 has problem with the cksum application. It doesn’t compute a checksum properly and the checksum failed message prevents the building of Openvswitch . Due to this reason, upgrade to BusyBox  1.18.4 is neccessary.

wget http://busybox.net/downloads/busybox-1.19.0.tar.bz2

tar jxvf ./busybox-1.19.0.tar.bz2

cd ./busybox-1.19.0/

make defconfig
make

sudo su

cd /home/tc/busybox-1.19.0/

make install

Replace cksum version 1.18.3 with 1.19.0. Cksum version 1.19.0 is stored in ./_install/usr/bin/

sudo cp ./_install/usr/bin/cksum /usr/bin/

5. Openvswitch Installation

It is recommended to start here and continue here :-) After that you can type following:

export CFLAGS="-march=i486 -mtune=i686 -Os -pipe"
export CXXFLAGS="-march=i486 -mtune=i686 -Os -pipe"
export LDFLAGS="-Wl,-O1"

cd ./openvswitch-1.2.2

./configure –prefix=/usr/local –with-linux=/lib/modules/`uname -r`/build

make -j2

touch /tmp/mark

sudo su

cd /home/tc/openvswitch-1.2.2/

make  DESTDIR=/tmp/openvswitch install

6. BACKUP and LOAD Module openvswitch_mod_ko

a) BACKUP module openvswitch_mod_ko 

After building, a kernel module “openvswitch_mod_ko” will be saved in ./datapath/linux/openvswitch_mod.ko. We’ve built both userspace and kernel module as well.  The performance is better when a kernel module is used.

mkdir -p /tmp/openvswitch/usr/local/lib/modules/3.0.3-tinycore/kernel/openvswitch/

cp /home/tc/openvswitch-1.2.2/datapath/linux/openvswitch_mod.ko /tmp/openvswitch/usr/local/lib/modules/3.0.3-tinycore/kernel/openvswitch/

b) Check if module can be loaded correctly

mkdir -p /usr/local/lib/modules/3.0.3-tinycore/kernel/openvswitch/

cp /home/tc/openvswitch-1.2.2/datapath/linux/openvswitch_mod.ko /usr/local/lib/modules/3.0.3-tinycore/kernel/openvswitch/

depmod -a

modprobe openvswitch_mod

Check if module openvswitch_mod.ko is loaded to the kernel with lsmod command.

7. Backup /home/tc/openvswitch-1.1.1/vswitchd/vswitch.ovsschema

In order to initialize the configuration database using ovsdb-tool , file /home/tc/openvswitch-1.2.0/vswitchd/vswitch.ovsschema is needed. You need to copy it to /tmp/openvswitch/usr/local/etc/openvswitch/vswitchd/ as we want to have it as a part of submitted Openvswitch extension.

mkdir -p /tmp/openvswitch/usr/local/etc/openvswitch/vswitchd/

cp /home/tc/openvswitch-1.2.2/vswitchd/vswitch.ovsschema /tmp/openvswitch/usr/local/etc/openvswitch/vswitchd/

8. Create Openvswitch Extension

a) Remove unneccessary files

rm -rf /tmp/openvswitch/usr/local/share/man/

b) Install squashfs and create openvswitch.tcz extension

tce-load -w -i squashfs-tools-4.x

sudo su

cd /tmp/

mksquashfs openvswitch/ openvswitch.tcz

c) Create a list of files presented in extension

cd /tmp/openvswitch/

sudo su

find usr -not -type d > ../openvswitch.tcz.list

d) Create md5 check sum of openvswitch.tcz

cd /tmp/ ls

md5sum openvswitch.tcz > openvswitch.tcz.md5.txt

e) Create openvswitch.tcz.info

an info file describing its contents (.tcz.info) – this content is standardized. Check repository for examples.

f) Create build-dep file

additional build instructions in a plain text file for future reference, mentioning such things as which extensions are required to build the package and what compile flags were used.

g) Create the dependency list openvswitch.tcz.dep

List of the extensions that have to be presented to run openvswitch extension correctly.

9. Test and Submit Openvswitch Extension

a) Create the new  clean Microcore Qemu image without any extensions installed

Assuming an image is ready to start, run it:

qemu-kvm /home/brezular/linux-microcore-4.0-clean.img -m 512

b) Install submitqc.tcz

tce-load -wi submitqc4.tcz

c) Copy the openvswitch files you have created in steps 1 – 8

(.tcz, .list, .md5.txt, .info, .dep, build-dep) from old Qemu image to the clean Qemu image, to the directory  /tmp/.

cd /tmp/

Run script:

sudo submitqc4

Script checks all openvswitch files in /tmp/ and create the directory /tmp/submitqc/ with log files.

d) Send extension

Note: If they are another files in /tmp/ , create directory /tmp/All and move openvswitch files, submitqc directory and openvswitch source to /tmp/All/

mv /tmp/openvswitch* /tmp/All/

sudo mv /tmp/submitqc/ /tmp/build-dep /tmp/All/

cd /tmp/All

sudo tar zcf openvswitch-1.2.2-extension.tar.gz *

sudo bcrypt openvswitch-1.2.2-extension.tar.gz

Password for bcrypt operation is tinycore Send openvswitch.tar.gz.bfe to  tcesubmit@gmail.com

10. Openvswitch After-Install Configuration

a) Make openvswitch_mod_ko, 8021q, ipv6 modules to be loaded to the kernel during boot of Microcore

echo "modprobe openvswitch_mod" >> /opt/bootlocal.sh>
echo "modprobe 8021q" >> /opt/bootlocal.sh
echo "modprobe ipv6" >> /opt/bootlocal.sh

sudo modprobe openvswitch_mod
sudo modprobe 8021q
sudo modprobe ipv6

b) Initialize the configuration database using ovsdb-tool

Check if a directory /usr/local/etc/openvswitch/ exists, if not create it.

sudo mkdir -p /usr/local/etc/openvswitch/

Create conf.db configuration file.

sudo ovsdb-tool create /usr/local/etc/openvswitch/conf.db /usr/local/etc/openvswitch/vswitchd/vswitch.ovsschema

Add /usr/local/etc/openvswitch/ to the list of after restart kept files.

echo "/usr/local/etc/openvswitch/" >> /opt/.filetool.lst

c) Make ovsdb-server to be started after start of the Microcore

vi /opt/bootlocal.sh

/usr/local/sbin/ovsdb-server --remote=punix:/usr/local/var/run/openvswitch/db.sock --remote=db:Open_vSwitch,manager_options --private-key=db:SSL,private_key --certificate=db:SSL,certificate --bootstrap-ca-cert=db:SSL,ca_cert --pidfile --detach

:wq!

Note:  If you are not familiar with vi editor, use the reference below, please:

http://nemesis.lonestar.org/reference/docs/vi.html

d) Make the database initialialization using ovs-vsctl

This is only necessary the first time after you create the database with ovsdb-tool (but running it at any time is harmless).

echo "/usr/local/bin/ovs-vsctl --no-wait init" >> /opt/bootlocal.sh

e) Make the main Open vSwitch daemon being started, telling it to connect to the same Unix domain socket

echo "/usr/local/sbin/ovs-vswitchd --pidfile --detach" >> /opt/bootlocal.sh

f) Enable IPv4 and IPV6 packets forwarding between interfaces

Although not directly connected with Openvswitch configuration we need to enable ipv4 and ipv6 packets forwarding between interfaces for Microcore.  This option  is disabled in kernel by default.

sudo sysctl -w net.ipv4.ip_forward=1
sudo sysctl -w net.ipv6.conf.all.forwarding=1

echo "sysctl -w net.ipv4.ip_forward=1" >> /opt/bootlocal.sh
echo "sysctl -w net.ipv6.conf.all.forwarding=1" >> /opt/bootlocal.sh

g) Run commands you have entered into  /opt/bootlocal.sh and make them persistent after restart of the Microcore

sudo /opt/bootlocal.sh

Optionally: It is recommended to delete the history of used commands.

echo "" > /home/tc/.ash_history

Save changes made for files and directories which are listed in  /opt/.filetool.lst

/usr/bin/filetool.sh -b

11. Configuration example

Now you may use ovs-vsctl to set up bridges and other Open vSwitch features.  For example, to create a bridge named br0 and add ports eth0, eth1  and eth2 to it:

sudo ovs-vsctl add-br br0

sudo ovs-vsctl add-port br0 eth0
sudo ovs-vsctl add-port br0 eth1
sudo ovs-vsctl add-port br0 eth2

Before shutdown you always force Microcore to save configuration changes in the openvswitch database file -  /usr/local/etc/openvswitch/conf.db

/usr/bin/filetool.sh -b

Reference
http://openvswitch.org/
http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=INSTALL.userspace;hb=HEAD
http://openvswitch.org/?page_id=14
http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=INSTALL.Linux;hb=HEAD

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