Overlay networking enables to implement tunnels to interconnect networks defined inside a host (such as Docker/Podman private networks): for example flannel based Kubernetes uses VxLANs to interconnect the Minion’s private networks. Anyway VxLAN is only one of the available technologies: other technologies such as GENEVE, STT or NVGRE are available.
In this post we setup a GENEVE tunnel with OpenVSwitch and Podman - the described set up goes beyond the simple interconnection on of layer 3 network segments, interconnecting two Podman’s private networks configured with the same IP subnet (so they share the same broadcast domain) - the layer 2 data are exchange between the OpenVSwitch bridges on the two hosts through the GENEVE tunnel.