For people with large WebSocket workloads using the ingress-nginx controller.
I recently hit this issue:
https://github.com/kubernetes/ingress-nginx/issues/2461
This drops all current WebSocket connections when ever the controller reloads the config. This can be triggered by adding/removing a new Ingress object (which this project does regularly due to customer load).
We ended up moving the WebSocket ingress to a separate LoadBalancer/Ingress class.