OVN and Red Hat Virtualization: Provisioning OVN

Hi folks, in this final post on RHV and OVN I’m going to show you how to utilize everything we’ve learned and installed up to this point. We’ve installed the packages, now it’s just a matter of deploying some virtual machines and attaching them to the new OVN provided SDN. As before my colleague, Tony James walks us through the process. Let’s get started.

Like any other integration in Red Hat Virtualization, we access OVN by way of the External Provider feature. In short, the External Provider allows RHV to take advantage of resources managed by external sources, in this case SDN.

Let’s post the video first, the walk through follows:

Add an External Network Provider

The External Provider dialog is launched from the “tree” menu on the far left of the dashboard. We give the network a name and because the OVN controller was deployed on the RHV-M host, the external provider simply points at the local host and port 9696. The external provider type is “External Network Provider”, and the “Read Only” box is unchecked.

Add a Network

Under the “Network” tab, click “New” and enter a name for the new SDN. Check the “Create on external provider” box and the External Network Provider will auto-populate. Click “ok”. Running the `ovn-nbctl show` command on the OVN controller (the RHV-M host in this case) now shows the creation of a switch.

Create VMs

For the sake of the demo, 2 RHEL VMs are created. They both have the default “ovirtmgmt” networks ( to start. Once they are created and operational, the SDN interfaces are plumbed on a private ( network. The uses are numerous, but the example provided is a private application network between VMs that doesn’t use the primary interfaces for routing.

Testing the connection

In the demo, Tony pings the the private interfaces as well as shows the routing table. And then proves the “privacy” of the connection by dropping one of the SDN plumbed interfaces and re-trying the ping. When it fails, it shows there is no way that the routing goes through the default gateway and only through the private network.

Wrapping up

As I mentioned, the demo shows a private network. That could be for applications, managing a lab, security, or any number of uses. You could certainly setup multiple SDNs for tenancy and clients. More importantly, I see this as a positive blurring of the lines between “cloud services” and traditional virtualization.

hope this helps,

Captain KVM

2 thoughts on “OVN and Red Hat Virtualization: Provisioning OVN”

  1. Hello,
    what if we want to separate vm traffic on the same the network? I mean: I want to avoid that vm1 speaks with vm2 when they both are on the same subnet. I mean something like PVLAN.

    Thank you for your time
    Alessio Dini

    1. Hi Allessio,

      Apologies for the delayed response. Separating traffic can still be done with VLANs and/or firewalld. That doesn’t change just because of OVN, that’s one of the really great things about SDN in general.

      Captain KVM

Agree? Disagree? Something to add to the conversation?