Communication between kubernetes pods using domain sockets
There is no native way to do this in Kubernetes, however you may apply the same approach like the one described in this Serverfault answer - theoretically should be achievable in K8S too.
Translating it from pure containers way to Kubernetes one, it would required you to simply mount/share the same Persistent Volume with subPath to socket file to all Pods on the same Kubernetes Node. Pick the PV type that allows mounting local storage in RWX access mode.
Known to me limitation: only Pods on the same Node can share the same Unix socket file.