OpenvSwitch compile - RHEL 7, CentOS 7, Fedora 25

Note: for Fedora, use dnf instead of yum

I will not advocate why we should use OpenvSwitch instead of Linux bridges, reasons are numerous. OpenvSwitch brings all Software Defined Network (SDN) capabilities within linux Operating System. Open vSwitch is a production quality, multilayer virtual switch licensed under the open source Apache 2.0 license. It is designed to enable massive network automation through programmatic extension, while still supporting standard management interfaces and protocols (e.g. NetFlow, sFlow, IPFIX, RSPAN, CLI, LACP, 802.1ag). In addition, it is designed to support distribution across multiple physical servers similar to VMware's vNetwork distributed vswitch or Cisco's Nexus 1000V.

To use the latest rpm version of OpenvSwitch (2.7.0 for example) instead of the one's available in the epel repository.

Install necessary binaries to build rpm:

$ sudo yum -y install gcc openssl-devel selinux-policy-devel

Create rpm build environment:

$ sudo yum install -y rpmdevtools
$ cd ~
$ rpmdev-setuptree

The latest command will create the folder ~/rpmbuild.

Download and extract in ~/rpmbuild/SOURCES the latest version of OpenvSwitch binary from http://openvswitch.org:

$ wget -qO- http://openvswitch.org/releases/openvswitch-2.x.y.tar.gz | tar xvz -C ~/rpmbuild/SOURCES

Build rpms from openvswitch spec file:

$ rpmbuild -bb ~/rpmbuild/SOURCES/openvswitch-2.x.y/rhel/openvswitch.spec   

OpenvSwitch rpms can now be installed from ~/rpmbuild/RPMS folder:

$ sudo yum -y install ~/rpmbuild/RPMS/noarch/openvswitch-selinux-policy-2.x.y-z.noarch.rpm
$ sudo yum -y install ~/rpmbuild/RPMS/x86_64/openvswitch-2.x.y-z.x86_64.rpm

Enable and start OpenvSwitch:

# systemctl enable openvswitch
# systemctl start openvswitch

Run our first OpenvSwitch command:

# ovs-vsctl show
    ovs_version: "2.7.0"

In my example i am running the version 2.7.0 of OpenvSwitch.

Libvirt & OpenvSwitch

We assume that libvirtd and OpenvSwitch are enable and running on the system. Let's create three (03) subnets with OpenvSwitch bridges (ovsbr-dmz, ovsbr-int, ovsbr-noc) and map them to libvirt networks. OpenvSwitch subnets are identified by the following parameters:

ovsbr-noc:
   ip: 10.30.0.1/24
ovsbr-int:
   ip: 10.10.0.1/24
ovsbr-dmz:
   ip: 10.20.0.1/24 

###Permanent network configurations on RedHat, CentOS and Fedora:

/etc/sysconfig/network-scripts/ifcfg-ovsbr-int

DEVICE=ovsbr-int
ONBOOT=yes
DEVICETYPE=ovs
TYPE=OVSBridge
BOOTPROTO=static
IPADDR=10.10.0.1
NETMASK=255.255.255.0
HOTPLUG=no
ZONE=public

/etc/sysconfig/network-scripts/ifcfg-ovsbr-dmz

DEVICE=ovsbr-dmz
ONBOOT=yes
DEVICETYPE=ovs
TYPE=OVSBridge
BOOTPROTO=static
IPADDR=10.20.0.1
NETMASK=255.255.255.0
HOTPLUG=no
ZONE=public

/etc/sysconfig/network-scripts/ifcfg-ovsbr-noc

DEVICE=ovsbr-noc
ONBOOT=yes
DEVICETYPE=ovs
TYPE=OVSBridge
BOOTPROTO=static
IPADDR=10.30.0.1
NETMASK=255.255.255.0
HOTPLUG=no
ZONE=public

These commands on system boot will create OpenvSwitch bridges with the configured ip addresses.

Create three (03) Libvirt network's xml files mapped to the OpenvSwitch bridges:

ovsbr-dmz.xml

<network>
  <name>ovsbr-dmz</name>
  <forward mode='bridge'/>
  <bridge name='ovsbr-dmz'/>
  <virtualport type='openvswitch'/>
</network>

Define and start the ovsbr-dmz network

  # virsh net-define ovsbr-dmz.xml
  # virsh net-autostart ovsbr-dmz
  # virsh net-start ovsbr-dmz

ovsbr-int.xml

<network>
  <name>ovsbr-int</name>
  <forward mode='bridge'/>
  <bridge name='ovsbr-int'/>
  <virtualport type='openvswitch'/>
</network>

Define and start the ovsbrt-int network

  # virsh net-define ovsbr-int.xml
  # virsh net-autostart ovsbr-int
  # virsh net-start ovsbr-int

ovsbr-noc.xml

<network>
  <name>ovsbr-noc</name>
  <forward mode='bridge'/>
  <bridge name='ovsbr-noc'/>
  <virtualport type='openvswitch'/>
</network>

Define and start the ovsbr-noc network

  # virsh net-define ovsbr-noc.xml
  # virsh net-autostart ovsbr-noc
  # virsh net-start ovsbr-noc

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