I am creating a Facebook multiplayer game and am currently evaluating my tech stack.
My game would need to use websockets and I would like to use Spring Boot. Now, I can not find the info if websocket server will work nicely in Kubernetes? For example if I deploy 5 instances of the server in Kubernetes pods will load balancing/forwarding work correctly for websockets between game clients loaded in browsers and servers in Kubernetes and is there any additional work to enable it? Each pod/server would be stateless and current game info for each player will be stored/read from redis or some other memory db.
If this would not work, how can I work around it and still use Kubernetes? Maybe add one instance of rabbitmq to the stack just for the websockets?
An adequate way to handle this would be to use "sticky sessions". This is where the user is pinned down to a specific pod based on the setting of a cookie.
Here is an example of configuring the Ingress resource object to use sticky sessions:
#
# https://github.com/kubernetes/ingress-nginx/tree/master/docs/examples/affinity/cookie
#
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: nginx-test-sticky
annotations:
kubernetes.io/ingress.class: "nginx"
ingress.kubernetes.io/affinity: "cookie"
ingress.kubernetes.io/session-cookie-name: "route"
ingress.kubernetes.io/session-cookie-hash: "sha1"
spec:
rules:
- host: $HOST
http:
paths:
- path: /
backend:
serviceName: $SERVICE_NAME
servicePort: $SERVICE_PORTNow with that being said, the proper way to handle this would be to use a message broker or a websocket implementation that supports clustering such as socketcluster (https://socketcluster.io).