Is OVN usable strictly if you have a L2 network available with unused interface? What solution is there for lower budget projects, that would use either cloud servers or even dedicated servers, where you'd get a vswitch with a vlan to use on the single interface used to connect to the internet also?
When dealing with multiple servers and you want a proper HA environment, then yeah, you need to have a shared L2 network across all servers. But you can still use OVN even if you don't. You can use a regular Incus bridge as the uplink network. In that scenario, the external address can't properly move between servers, so if a server goes down and another takes over as the external facing gateway for an OVN network, all connections on that network will break and have to be re-established, but that's the main impact there. I have a few customers running OVN on the public cloud and it's been working fine with those limitations.
Is OVN usable strictly if you have a L2 network available with unused interface?
What solution is there for lower budget projects, that would use either cloud servers or even dedicated servers, where you'd get a vswitch with a vlan to use on the single interface used to connect to the internet also?
When dealing with multiple servers and you want a proper HA environment, then yeah, you need to have a shared L2 network across all servers.
But you can still use OVN even if you don't. You can use a regular Incus bridge as the uplink network.
In that scenario, the external address can't properly move between servers, so if a server goes down and another takes over as the external facing gateway for an OVN network, all connections on that network will break and have to be re-established, but that's the main impact there.
I have a few customers running OVN on the public cloud and it's been working fine with those limitations.