Attention: This answer applies to the ingress-nginx solution provided by the kubernetes organisation on github (https://github.com/kubernetes/ingress-nginx)

---

If you want to use load balancing mechanisms in k8s you should use services instead and start multiple instances behind that service that way k8s will do the load balancing. If you want to use different versions of your backend (e.g. prod and test) your way of separating them is fine

if your service is only reachable via https you need to add the following annotation to your ingress yaml: (documentation)

nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"

To secure ingress itself take a look at this: https://kubernetes.io/docs/concepts/services-networking/ingress/#tls

But if you want that the backend services decrypt the TLS communication use the following annotation instead: (documentation)

nginx.ingress.kubernetes.io/ssl-passthrough: "true"

Edit:

The Ingress YAML should look like this if you want to reach the backend via TLS:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-name
  namespace: namespace-name 
  annotations:
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
spec:
  rules:
  - http:
      paths:
      - backend:
          serviceName: service
          servicePort: 9443
        path: /carbon
      - backend:
          serviceName: service2
          servicePort: 9443
        path: /oauth

The Ingress YAML should look like this if you want to reach the backend via TLS with TLS decryption in the ingress controller:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-name
  namespace: namespace-name 
  annotations:
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
spec:
  tls:
  - hosts:
    - app.myorg.com
    secretName: tls-secret 
  rules:
  - http:
      paths:
      - backend:
          serviceName: service
          servicePort: 9443
        path: /carbon
      - backend:
          serviceName: service2
          servicePort: 9443
        path: /oauth

It's important to note that tls-secret is the name of a SecretConfig with a valid Certificate issued for the host (app.myorg.com)

---

The Ingress YAML should look like this if you want to reach the backend via TLS with TLS decryption in the backend:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-name
  namespace: namespace-name 
  annotations:
    nginx.ingress.kubernetes.io/ssl-passthrough: "true"
spec:
  rules:
  - http:
      paths:
      - backend:
          serviceName: service
          servicePort: 9443
        path: /carbon
      - backend:
          serviceName: service2
          servicePort: 9443
        path: /oauth

I never tested the last version myself so i don't know if that actually works but I'd strongly advise reading this passage for that variant.

If you are using the NGINX Ingress controller (https://docs.nginx.com/nginx-ingress-controller/),

the nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"

does not work. However, the

nginx.org/ssl-services

will let you pick the services that require TLS on the backend. The name is confusing, so it took me a while to realize the real purpose of it.

This does not work with the standard Kubernetes Ingress controller that uses NGINX under the hood; it only works with the NGINX-sourced controller.

Advanced annotation docs: https://docs.nginx.com/nginx-ingress-controller/configuration/ingress-resources/advanced-configuration-with-annotations/

In this example, NGINX will connect to the

ssl-svc

using TLS; it ignores any self-signed certificates. Example (https://github.com/nginxinc/kubernetes-ingress/tree/v1.12.0/examples/ssl-services):

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: cafe-ingress
  annotations:
    nginx.org/ssl-services: "ssl-svc"
spec:
  rules:
  - host: cafe.example.com
    http:
      paths:
      - path: /tea
        backend:
          serviceName: tea-svc
          servicePort: 80
      - path: /coffee
        backend:
          serviceName: coffee-svc
          servicePort: 80
      - path: /ssl
        backend:
          serviceName: ssl-svc
          servicePort: 443

Using Ingress-nginx I was getting certificate errors even using

nginx.ingress.kubernetes.io/upstream-vhost: example.com

; it wasn’t sending the

Host

header for some reason. To get it working, I had to use:

    nginx.ingress.kubernetes.io/server-snippet: |
      proxy_ssl_name example.com; //your upstream hostname here
      proxy_ssl_server_name on;
    nginx.ingress.kubernetes.io/ssl-passthrough: "true"
    nginx.ingress.kubernetes.io/backend-protocol: “HTTPS"