shettyg/ovn-namespace

Installing OVN from source

• Clone the OVS repo.

• Compile:

./boot.sh
./configure --prefix=/usr --localstatedir=/var  --sysconfdir=/etc --enable-ssl --with-linux=/lib/modules/`uname -r`/build
make -j3
make install

• Insert kernel modules

rmmod openvswitch
modprobe libcrc32c
modprobe nf_conntrack_ipv6
modprobe nf_nat_ipv6
modprobe gre
insmod ./datapath/linux/openvswitch.ko
insmod ./datapath/linux/vport-geneve.ko

• Copy a startup script

cp debian/openvswitch-switch.init /etc/init.d/openvswitch-switch

• Start Open vSwitch

/etc/init.d/openvswitch-switch start

• Start OVN central components

/usr/share/openvswitch/scripts/ovn-ctl restart_northd

Open up TCP ports.

ovn-nbctl set-connection ptcp:6641
ovn-sbctl set-connection ptcp:6642

• One time setup on each host On each host, where you plan to spawn your containers, you will need to run the following command once. (You need to run it again if your OVS database gets cleared. It is harmless to run it again in any case.)

$LOCAL_IP in the below command is the IP address via which other hosts can reach this host. This acts as your local tunnel endpoint.

$ENCAP_TYPE is the type of tunnel that you would like to use for overlay networking. The options are "geneve" or "stt". (Please note that your kernel should have support for your chosen $ENCAP_TYPE. Both geneve and stt are part of the Open vSwitch kernel module that is compiled from this repo. If you use the Open vSwitch kernel module from upstream Linux, you will need a minumum kernel version of 3.18 for geneve. There is no stt support in upstream Linux. You can verify whether you have the support in your kernel by doing a "lsmod | grep $ENCAP_TYPE".)

ovs-vsctl set Open_vSwitch . external_ids:ovn-remote="tcp:$CENTRAL_IP:6642" \
  external_ids:ovn-encap-ip=$LOCAL_IP external_ids:ovn-encap-type="$ENCAP_TYPE"

And finally, start the ovn-controller. (You need to run the below command on every boot)

/usr/share/openvswitch/scripts/ovn-ctl start_controller

Creating a simple topology with OVN using namespaces.

• Create logical switches "foo" and "bar"

ovn-nbctl ls-add foo
ovn-nbctl ls-add bar

• Create a router "router"

sh ovn-router.sh create-router router

• Connect switch "foo" to "router". The router port gets an ip address of 192.168.100.1/24

sh ovn-router.sh connect-switch router foo 192.168.100.1/24

• Connect switch "bar" to "router. The router port gets an ip address of 192.168.200.1/24

sh ovn-router.sh connect-switch router bar 192.168.200.1/24

• Create a namespace "foo1" and attach it as a logical port "foo1". You need to run this command on the machine you plan to spawn your namespace. If that machine is different than the machine where your northbound database runs, then you need to provide the --db option. e..g --db=tcp:10.33.75.67:6641

sh ovn-port.sh add-port foo foo1 192.168.100.2/24 192.168.100.1

• Create a namespace "bar1" and attach it as a logical port "bar1"

sh ovn-port.sh  add-port --db=tcp:$IP:6641 bar bar1 192.168.200.2/24 192.168.200.1

• Test your pings

ip netns exec foo1 ping 192.168.200.2