Open vSwitch (OVS) is a production-grade virtual switch that brings data center networking features to Linux hypervisors. While the standard Linux bridge handles basic L2 switching, OVS adds VLAN trunking, port mirroring, sFlow/NetFlow monitoring, OpenFlow support, and DPDK acceleration – features that matter when you are running dozens of VMs with complex network requirements. This guide covers installing OVS on Ubuntu 24.04 and RHEL 10, creating bridges and ports, configuring VLANs, integrating with KVM/libvirt, and an overview of OVS-DPDK for high-performance workloads.

What is Open vSwitch

Open vSwitch is a multilayer virtual switch designed to work in virtualized server environments. It supports standard management interfaces like NetFlow, sFlow, IPFIX, RSPAN, CLI, LACP, and 802.1ag. It was built to handle the networking needs of large-scale virtualization deployments where the standard Linux bridge falls short.

Key capabilities that matter for KVM administrators:

  • VLAN tagging and trunking – isolate VM traffic without separate physical interfaces
  • Port mirroring – capture traffic for monitoring or troubleshooting
  • QoS policies – rate limit VM traffic per port
  • OpenFlow support – programmable flow rules for SDN integration
  • GRE/VXLAN/Geneve tunneling – connect VMs across hosts without L2 adjacency
  • DPDK integration – kernel-bypass networking for near-line-rate performance

Prerequisites

  • A KVM host running Ubuntu 24.04 or RHEL 10
  • Root or sudo access
  • At least one physical network interface
  • Console access recommended when reconfiguring network interfaces

Installing Open vSwitch on Ubuntu 24.04

OVS is available in the Ubuntu repositories.

sudo apt update
sudo apt install -y openvswitch-switch

Verify the installation and check the service status.

sudo systemctl status openvswitch-switch
ovs-vsctl --version

Expected output will show OVS version 3.x running and active.

Installing Open vSwitch on RHEL 10

On RHEL 10, OVS is available through the standard repositories or the Fast Datapath repository.

sudo dnf install -y openvswitch3.3

Enable and start the service.

sudo systemctl enable --now openvswitch
sudo systemctl status openvswitch

Verify.

ovs-vsctl --version
ovs-vsctl show

Step 1 – Create an OVS Bridge

Create a new OVS bridge that will serve as the virtual switch for your VMs.

sudo ovs-vsctl add-br ovsbr0

Verify the bridge was created.

sudo ovs-vsctl show

You should see the bridge listed with its UUID.

Step 2 – Add Physical Ports to the Bridge

Add your physical network interface to the OVS bridge. This is similar to adding an interface to a Linux bridge, but OVS manages the switching.

sudo ovs-vsctl add-port ovsbr0 enp3s0

After adding the physical interface, move the IP address from the physical interface to the OVS bridge. If you are doing this remotely, script the entire process to avoid losing connectivity.

sudo ip addr flush dev enp3s0
sudo ip addr add 192.168.1.100/24 dev ovsbr0
sudo ip link set ovsbr0 up
sudo ip route add default via 192.168.1.1

Verify the bridge has the IP and the port is attached.

ip addr show ovsbr0
sudo ovs-vsctl show

To make this persist across reboots on Ubuntu 24.04, configure it in Netplan.

# /etc/netplan/01-ovs.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      dhcp4: false
  bridges:
    ovsbr0:
      openvswitch: {}
      interfaces:
        - enp3s0
      addresses:
        - 192.168.1.100/24
      routes:
        - to: default
          via: 192.168.1.1
      nameservers:
        addresses:
          - 8.8.8.8

Apply with sudo netplan apply.

On RHEL 10, use nmcli to manage the OVS bridge persistently.

sudo nmcli connection add type ovs-bridge con-name ovsbr0 conn.interface ovsbr0
sudo nmcli connection add type ovs-port con-name ovs-port-br conn.interface ovsbr0 master ovsbr0
sudo nmcli connection add type ovs-interface con-name ovs-iface-br conn.interface ovsbr0 \
  master ovs-port-br ipv4.method manual ipv4.addresses 192.168.1.100/24 ipv4.gateway 192.168.1.1 ipv4.dns "8.8.8.8"
sudo nmcli connection add type ovs-port con-name ovs-port-enp3s0 conn.interface enp3s0 master ovsbr0
sudo nmcli connection add type ethernet con-name ovs-enp3s0 conn.interface enp3s0 master ovs-port-enp3s0

Step 3 – Configure VLANs with OVS

One of the biggest advantages of OVS over a Linux bridge is proper VLAN support. You can assign access VLANs to specific ports so different VMs land on different network segments.

First, make sure the physical uplink port is configured as a trunk that carries all VLANs.

sudo ovs-vsctl set port enp3s0 trunks=100,200,300

To add a VM port with a specific VLAN tag (access port).

sudo ovs-vsctl add-port ovsbr0 vnet0 tag=100

This tags all traffic from vnet0 with VLAN 100. The VM does not need to know about VLANs – the tagging happens at the switch level.

To create a trunk port for a VM that needs access to multiple VLANs (like a router VM).

sudo ovs-vsctl add-port ovsbr0 vnet1 trunks=100,200

Verify VLAN configuration.

sudo ovs-vsctl list port vnet0
sudo ovs-vsctl show

Step 4 – Integrate OVS with KVM/libvirt

To use OVS bridges with libvirt, you need to define a libvirt network that references the OVS bridge. Create an XML definition file.

cat <<EOF > /tmp/ovs-network.xml
<network>
  <name>ovs-network</name>
  <forward mode='bridge'/>
  <bridge name='ovsbr0'/>
  <virtualport type='openvswitch'/>
</network>
EOF

Define, start, and auto-start the network.

virsh net-define /tmp/ovs-network.xml
virsh net-start ovs-network
virsh net-autostart ovs-network

Verify the network.

virsh net-list --all

Now create VMs that use the OVS network.

virt-install \
  --name ovs-vm \
  --ram 2048 \
  --vcpus 2 \
  --disk size=20 \
  --os-variant ubuntu24.04 \
  --network network=ovs-network,model=virtio \
  --cdrom /var/lib/libvirt/images/ubuntu-24.04.iso

To assign a specific VLAN to a VM through libvirt, edit the VM XML.

virsh edit ovs-vm

Set the interface section with VLAN configuration.

<interface type='network'>
  <source network='ovs-network'/>
  <virtualport type='openvswitch'/>
  <vlan>
    <tag id='100'/>
  </vlan>
  <model type='virtio'/>
</interface>

Step 5 – Useful OVS Management Commands

Here are commands you will use regularly when managing OVS.

Show the full OVS configuration.

sudo ovs-vsctl show

List all bridges.

sudo ovs-vsctl list-br

List ports on a bridge.

sudo ovs-vsctl list-ports ovsbr0

Delete a port from the bridge.

sudo ovs-vsctl del-port ovsbr0 vnet0

Check flow statistics.

sudo ovs-ofctl dump-flows ovsbr0

Show port statistics (packet counts, errors).

sudo ovs-ofctl dump-ports ovsbr0

Set port mirroring to capture all traffic from one port to another.

sudo ovs-vsctl -- set bridge ovsbr0 mirrors=@m \
  -- --id=@vnet0 get port vnet0 \
  -- --id=@mirror0 get port mirror0 \
  -- --id=@m create mirror name=mymirror select-src-port=@vnet0 select-dst-port=@vnet0 output-port=@mirror0

OVS-DPDK for High-Performance Networking

For workloads that demand maximum network throughput – think NFV (Network Function Virtualization), telecom, or high-frequency data processing – OVS-DPDK provides kernel-bypass networking. Instead of packets traversing the kernel network stack, DPDK processes them in userspace with dedicated CPU cores and hugepage memory, achieving near-line-rate performance.

Prerequisites for OVS-DPDK

  • A NIC that supports DPDK (Intel X710, Mellanox ConnectX series, etc.)
  • Hugepages configured in the kernel
  • CPU cores dedicated to DPDK processing

Configure hugepages. Add to the kernel command line or set at runtime.

echo 2048 | sudo tee /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
sudo mkdir -p /dev/hugepages
sudo mount -t hugetlbfs none /dev/hugepages

Install OVS with DPDK support.

# Ubuntu
sudo apt install -y openvswitch-switch-dpdk

# RHEL
sudo dnf install -y openvswitch3.3-dpdk

Enable DPDK in OVS.

sudo ovs-vsctl set Open_vSwitch . other_config:dpdk-init=true
sudo ovs-vsctl set Open_vSwitch . other_config:dpdk-socket-mem="1024"
sudo systemctl restart openvswitch-switch

Create a DPDK-enabled bridge and add a DPDK port.

sudo ovs-vsctl add-br dpdk-br -- set bridge dpdk-br datapath_type=netdev
sudo ovs-vsctl add-port dpdk-br dpdk0 -- set interface dpdk0 type=dpdk options:dpdk-devargs=0000:03:00.0

The dpdk-devargs value is the PCI address of your NIC. Find it with dpdk-devbind.py --status.

For VMs to use DPDK-accelerated ports, configure vhost-user ports.

sudo ovs-vsctl add-port dpdk-br vhost-user0 -- set interface vhost-user0 type=dpdkvhostuserclient options:vhost-server-path=/tmp/vhost-user0

OVS-DPDK configuration is significantly more involved than standard OVS and requires careful CPU pinning, NUMA awareness, and memory allocation planning. It is worth the effort for performance-critical workloads, but overkill for general-purpose virtualization.

Summary

Open vSwitch transforms a KVM host’s networking from basic bridge switching to a full-featured virtual network infrastructure. The installation is straightforward on both Ubuntu 24.04 and RHEL 10, and the ovs-vsctl command-line tool gives you complete control over bridges, ports, VLANs, and advanced features. For most deployments, standard OVS with VLAN support and libvirt integration covers everything you need. When you hit the limits of kernel-based switching, OVS-DPDK is there to push performance to the hardware limits. Whether you are running a handful of VMs or building an SDN-driven cloud, Open vSwitch gives you the networking toolkit to match.

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