Question 201688 in Redis Question posted in
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Redis – flask-socketio in kubernetes, ingress and multiple replicas

i’m running a flask-socketio behind an ingress.
here’s the config:

socketio = SocketIO(app, message_queue='redis://redis-server.domain:6379')

in the dockerfile, it runs like so:

CMD ["gunicorn", "-k", "geventwebsocket.gunicorn.workers.GeventWebSocketWorker", "-w", "4", "--bind", "0.0.0.0:2731", "app:app"]

and the ingress is configured like this:

nginx.ingress.kubernetes.io/affinity: "cookie"
nginx.ingress.kubernetes.io/enable-ssl-passthrough: "true"
nginx.ingress.kubernetes.io/session-cookie-name: "route"

i also tried replacing "cookie" with "ip_hash"

whenever i add a second replica pod, it starts returning error 400, as if it contacts the pods interchangeably, and not sticking to the same server, thus breaking the socket.

any ideas?

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2

Answers


  1. Chosen as BEST ANSWER
    0

    i've selected Harsh Manvar's ansewer as the correct one, but adding details for future reference:

    in the service, sessionAffinity: ClientIP as suggested.

    the Run command in dockerfile:

    CMD ["gunicorn", "-k", "geventwebsocket.gunicorn.workers.GeventWebSocketWorker", "-w", "1", "--bind", "0.0.0.0:6138", "--timeout", "180", "app:app"]

    the requirements.txt:

    gunicorn
simple-websocket
gevent-websocket
gevent

    the socketio:

    socketio = SocketIO(app, message_queue='redis://redis-service.redis:6379')

    added to ingress:

    nginx.ingress.kubernetes.io/enable-ssl-passthrough: "true"
nginx.ingress.kubernetes.io/add-base-url: "true"
nginx.ingress.kubernetes.io/session-cookie-name: "route"
nginx.ingress.kubernetes.io/websocket-services: service-name
nginx.ingress.kubernetes.io/session-cookie-expires: "172800"
nginx.ingress.kubernetes.io/session-cookie-max-age: "172800"

  2. 0

    Ideally, it should have worked but try this .spec.sessionAffinity

    Set it to service

    .spec.sessionAffinity value will be ClientIP

    Service to POD sticky session

    kind: Service
apiVersion: v1
metadata:
  name: test-service
spec:
  selector:
    app: test-app
  ports:
  - name: http
    protocol: TCP
    port: 80
    targetPort: 80
  sessionAffinity: ClientIP
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