CODEWITHSUNDEEP
kubernetesudp
Cherry Zhang
Cherry Zhang

Reputation: 101

How to maintain udp session within a pod in kubernetes?

When receive udp packets, I want to get the source IP and source Port from the packet, and expect that doesn't change if the packet is from the same source(same IP and same Port). My packet is sent through kube-proxy in iptables mode, but when my packets paused several seconds, and then the source port would change, and set sessionAffinity to "ClientIP" doesn't work. It seems that udp session can only be kept several seconds. Any way to expand the session time, or keep the port stay the same when my packet sender's ip and port haven't changed?

Upvotes: 1

Views: 539

Answers (1)

Wytrzymały Wiktor
Wytrzymały Wiktor

Reputation: 13888

This is a community wiki answer. Feel free to expand it.

As already mentioned in the comments, you can try to use the NGINX Ingress Controller. The Exposing TCP and UDP services says:

Ingress does not support TCP or UDP services. For this reason this Ingress controller uses the flags --tcp-services-configmap and --udp-services-configmap to point to an existing config map where the key is the external port to use and the value indicates the service to expose using the format: <namespace/service name>:<service port>:[PROXY]:[PROXY]

The example shows how to expose the service kube-dns running in the namespace kube-system in the port 53 using the port 53:

apiVersion: v1
kind: ConfigMap
metadata:
  name: udp-services
  namespace: ingress-nginx
data:
  53: "kube-system/kube-dns:53"

If TCP/UDP proxy support is used, then those ports need to be exposed in the Service defined for the Ingress:

apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: LoadBalancer
  ports:
    - name: http
      port: 80
      targetPort: 80
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
    - name: proxied-tcp-9000
      port: 9000
      targetPort: 9000
      protocol: TCP
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

Upvotes: 1

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