[ovirt-users] Still running in to problems trying to implement OVN

[Mitchell Smith]

Hi List,

I was very happy to see overt added support for OVN recently, and it was a fairly strong factor in choosing overt for our current project, however being a very new feature with very little in the way of publicly available documentation, we are having some difficulties with implementation.

I have found a few very good articles on OVN itself and am comfortable with OVN cli for the most part, but translating that in to overt logical networks and NICs is proving to be quite a challenge.

As you might remember from one of my earlier posts, we do have some limitations with the current hosting provider also that make our network topology for this project less than ideal, but hopefully with OVN I can get to the desired outcome somehow.

So the first fairly big issue we run into relates to the  ovirtmgmt network, obviously this is a hard dependency of overt and it can’t be removed. As we only have one physical NIC in each server though, this causes some problems since we can’t also attach OVS to the same NIC as the ovirtmgmt bridge. Ideally we could set up OVN and just plug ovirtmgmt in to that network, but I can’t find any way to do that.

Secondly our public IPs each have a specific MAC attached to them, something in the 00:50:56 VMware prefix, I want to add these on OVN and then SNAT them to the VMs internal IP on the 10.x.x.x network, I can work out how to do this on the cli, but not in overt, should I just manually create these interfaces and then get overt to try and import them or similar?

As an alternative, am I making this type of network structure to complex by using OVN, and should I think about just creating a private address space using Tinc / PeerVPN / FreeLAN / similar, and then just set up a single VM with multiple interfaces on it acting as a router?

To try and explain the network structure a bit better, each server has one physical NIC with a public IP address, each server also has a /29, each individual IP has a MAC associated with it on the vendors firewall. I plan to have a private subnet across the whole cluster managed with OVN, which I will place VMs on. The public IPs will be transparently routed to the private IPs using OVN routers.

It’s less than ideal, but those are the constraints we have to work in for this project.

My final question is completely off topic for this mostly OVN themed email, but we have also been looking at ScaleIO from EMC, and it looks like a decent solution. We have built our proof of concept environment using Gluster but we are considering ScaleIO for the final implementation, and I was curious if anyone else had tried ScaleIO with overt, and did you find any advantages / disadvantages compared to Gluster?

I will end this rather long email here, but if anyone has tried to implement a similar network structure on overt, I would very much appreciate any suggestions you might have for the best way to proceed.

Thanks :)

Mitch