SSL passthrough not being configured for ingress-nginx backend

Question

I am running the nginx ingress controller in minikube via helm and I can see SSL passthrough is enabled in the controller by looking at the logs of the nginx ingress controller pod.

helm upgrade ingress stable/nginx-ingress --install --namespace kube-system --set "controller.extraArgs.annotations-prefix=nginx.ingress.kubernetes.io" --set "controller.extraArgs.enable-ssl-passthrough=" --set controller.hostNetwork=true

Internally I have a HTTPS REST API service exposed on port 19000. I want mutual TLS between a client and the service running inside k8s so I am trying to configure my ingress with SSL passthrough enabled but when I set the nginx.ingress.kubernetes.io/ssl-passthrough annotation to "true" on my ingress, the backend still shows sslPassthrough set to false and when I send requests to the service, nginx is stripping the TLS certificate from my requests.

Is there some configuration I am missing to enable SSL passthrough on the backend?

$ kubectl ingress-nginx --deployment ingress-nginx-ingress-controller -n kube-system backends
[
  {
    "name": "default-tlsapi-service-19000",
    "service": {
      "metadata": {
        "creationTimestamp": null
      },
      "spec": {
        "ports": [
          {
            "protocol": "TCP",
            "port": 19000,
            "targetPort": 19000,
            "nodePort": 30000
          }
        ],
        "selector": {
          "app": "tlsapi"
        },
        "clusterIP": "10.96.218.188",
        "type": "NodePort",
        "sessionAffinity": "None",
        "externalTrafficPolicy": "Cluster"
      },
      "status": {
        "loadBalancer": {}
      }
    },
    "port": 19000,
    "sslPassthrough": false,
    "endpoints": [
      {
        "address": "172.17.0.7",
        "port": "19000"
      }
    ],
    "sessionAffinityConfig": {
      "name": "",
      "mode": "",
      "cookieSessionAffinity": {
        "name": ""
      }
    },
    "upstreamHashByConfig": {
      "upstream-hash-by-subset-size": 3
    },
    "noServer": false,
    "trafficShapingPolicy": {
      "weight": 0,
      "header": "",
      "headerValue": "",
      "cookie": ""
    }
  }

ingress.yaml

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: tlsapi-ingress
  annotations:
    kubernetes.io/ingress.class: "nginx"
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
    nginx.ingress.kubernetes.io/ssl-passthrough: "true"
spec:
  rules:
  - host: tlsapi.k8s
  - http:
      paths:
      - path: /
        backend:
          serviceName: tlsapi-service
          servicePort: 19000

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: tlsapi-service
spec:
  type: NodePort
  selector:
    app: tlsapi
  ports:
    - port: 19000
      targetPort: 19000
      nodePort: 30000

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: tlsapi-deployment
spec:
  selector:
    matchLabels:
      app: tlsapi
  replicas: 1
  template:
    metadata:
      name: tlsapi-pod
      labels:
        app: tlsapi
    spec:
      containers:
      - name: tlsapi-container
        image: tlsapi:latest
        imagePullPolicy: IfNotPresent

Arghya Sadhu Arghya Sadhu · Accepted Answer · 2020-01-23T13:28:07

You need to start the nginx ingress controller with flag --enable-ssl-passthrough

You can provide this flag in the args section of nginx ingress controller deployment yaml

spec:
  # wait up to five minutes for the drain of connections
  terminationGracePeriodSeconds: 300
  serviceAccountName: nginx-ingress-serviceaccount
  containers:
    - name: nginx-ingress-controller
      image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:master
      args:
        - --enable-ssl-passthrough

You can confirm that the argument took effect by looking at nginx ingress controller logs and searching for Starting TLS proxy for SSL Passthrough.

SSL passthrough not being configured for ingress-nginx backend

2 Answers