If user wants to utilize basic auth or oauth at ingress, it can be done as described in official documentation or in our documentation.

This approach has one big security flaw. Authentication is required when connecting via ingress only, e.g., from outside of Kubernetes cluster. However, user of the platform can also connect from inside cluster directly to the corresponding service (they need to guess it IP though) and in such a case, there is no authentication required.

This flaw can be mitigated using Network Policy that can limit origin of network traffic. In this case, it is useful to allow ingress traffic to server from kube-system namespace only. The kube-system namespace hosts Ingress Nginx instance, therefore, connection from this and only this namespace is required.

Example of network policy can be downloaded here. This policy allows ingress traffic from kube-system to Pod named myapp. This policy is applied to the namespace where the Pod myapp is.

It is possible to utilize e-infra's SSO service to secure your application. To enable this, some data must be added to the ingress. We will show how to edit an existing ingress to include SSO.

This example represents an existing ingress:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-name
  annotations:
    kubernetes.io/ingress.class: "nginx"
    kubernetes.io/tls-acme: "true"
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
spec:
  tls:
    - hosts:
        - "hostname.dyn.cloud.e-infra.cz"
      secretName: hostname-dyn-cloud-e-infra-cz-tls
  rules:
  - host: "hostname.dyn.cloud.e-infra.cz"
    http:
      paths:
      - path: /
        backend:
          service:
            name: service-name
            port:
              number: port-number
        pathType: Prefix

Firstly, we must add a few annotations to the ingress itself:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-name
  annotations:
    kubernetes.io/ingress.class: "nginx"
    kubernetes.io/tls-acme: "true"
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
+   nginx.ingress.kubernetes.io/auth-url: "https://$host/oauth2/[email protected], [email protected], [email protected]"
+   nginx.ingress.kubernetes.io/auth-signin: "https://$host/oauth2/start?rd=$scheme%3A%2F%2F$host$escaped_request_uri"
spec:
  tls:
    - hosts:
        - "hostname.dyn.cloud.e-infra.cz"
      secretName: hostname-dyn-cloud-e-infra-cz-tls
  rules:
  - host: "hostname.dyn.cloud.e-infra.cz"
    http:
      paths:
      - path: /
        backend:
          service:
            name: service-name
            port:
              number: service-port-number
        pathType: Prefix

The nginx.ingress.kubernetes.io/auth-url annotation contains a query string which specifies a list of users that should be able to access the website, only change the list of emails in this field, do not change the URL in any way.

The other annotation simply tells the ingress that it should redirect back to the webpage after the user authenticates.

Now that the ingress is configured to use an SSO enpoint, we must configure the SSO endpoint itself. To do this we must apply the following YAML file:

apiVersion: v1
kind: Service
metadata:
  name: ingress-name-oauth
spec:
  type: ExternalName
  externalName: oauth2-proxy.kube-system.svc.cluster.local
  ports:
  - name: http
    port: 4180
    protocol: TCP

---

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-name-oauth
  annotations:
    kubernetes.io/ingress.class: "nginx"
    kubernetes.io/tls-acme: "true"
spec:
  tls:
    - hosts:
        - "hostname.dyn.cloud.e-infra.cz"
      secretName: hostname-dyn-cloud-e-infra-cz-tls
  rules:
  - host: "hostname.dyn.cloud.e-infra.cz"
    http:
      paths:
      - path: /oauth2
        backend:
          service:
            name: ingress-name-oauth
            port:
              number: 4180
        pathType: Prefix

Note that the hosts and secretName are the same as in the original ingress. The only thing that needs to be changed in the file is all occurences of ingress-name and hostname, replace them with the name of your ingress and web page URL and apply the file.

With all the changes applied, your webiste is now secured with the e-infra's SSO service.