Tutorial: Basic

These tutorials help illustrate the usage of Kubernetes Ingress Resources to expose an example Kubernetes service through the Azure Application Gateway over HTTP or HTTPS.

Table of Contents

Prerequisites

  • Installed ingress-azure helm chart.
  • Greenfield Deployment: If you are starting from scratch, refer to these installation instructions which outlines steps to deploy an AKS cluster with Application Gateway and install application gateway ingress controller on the AKS cluster.
  • Brownfield Deployment: If you have an existing AKS cluster and Application Gateway, refer to these instructions to install application gateway ingress controller on the AKS cluster.
  • If you want to use HTTPS on this application, you will need a x509 certificate and its private key.

Deploy guestbook application

The guestbook application is a canonical Kubernetes application that composes of a Web UI frontend, a backend and a Redis database. By default, guestbook exposes its application through a service with name frontend on port 80. Without a Kubernetes Ingress Resource the service is not accessible from outside the AKS cluster. We will use the application and setup Ingress Resources to access the application through HTTP and HTTPS.

Follow the instructions below to deploy the guestbook application.

  1. Download guestbook-all-in-one.yaml from here
  2. Deploy guestbook-all-in-one.yaml into your AKS cluster by running
kubectl apply -f guestbook-all-in-one.yaml

Now, the guestbook application has been deployed.

Expose services over HTTP

In order to expose the guestbook application we will using the following ingress resource:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: guestbook
  annotations:
    kubernetes.io/ingress.class: azure/application-gateway
spec:
  rules:
  - http:
      paths:
      - backend:
          service:
            name: frontend
            port:
              number: 80

This ingress will expose the frontend service of the guestbook-all-in-one deployment as a default backend of the Application Gateway.

Save the above ingress resource as ing-guestbook.yaml.

  1. Deploy ing-guestbook.yaml by running:

    kubectl apply -f ing-guestbook.yaml

  2. Check the log of the ingress controller for deployment status.

Now the guestbook application should be available. You can check this by visiting the public address of the Application Gateway.

Expose services over HTTPS

Without specified hostname

Without specifying hostname, the guestbook service will be available on all the host-names pointing to the application gateway.

  1. Before deploying ingress, you need to create a kubernetes secret to host the certificate and private key. You can create a kubernetes secret by running

    kubectl create secret tls <guestbook-secret-name> --key <path-to-key> --cert <path-to-cert>

  2. Define the following ingress. In the ingress, specify the name of the secret in the secretName section.

    apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: guestbook
  annotations:
    kubernetes.io/ingress.class: azure/application-gateway
spec:
  tls:
    - secretName: <guestbook-secret-name>
  rules:
  - http:
      paths:
      - backend:
          service:
            name: frontend
            port:
              number: 80

    NOTE: Replace <guestbook-secret-name> in the above Ingress Resource with the name of your secret. Store the above Ingress Resource in a file name ing-guestbook-tls.yaml.

  3. Deploy ing-guestbook-tls.yaml by running

    kubectl apply -f ing-guestbook-tls.yaml

  4. Check the log of the ingress controller for deployment status.

Now the guestbook application will be available on HTTPS.

In order to make the guestbook application available on HTTP, annotate the Ingress with

  appgw.ingress.kubernetes.io/ssl-redirect: "true"

Only in this case a HTTP Listener is created in Azure which redirects the visitor to the HTTPS version.

With specified hostname

You can also specify the hostname on the ingress in order to multiplex TLS configurations and services. By specifying hostname, the guestbook service will only be available on the specified host.

  1. Define the following ingress. In the ingress, specify the name of the secret in the secretName section and replace the hostname in the hosts section accordingly.

    apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: guestbook
  annotations:
    kubernetes.io/ingress.class: azure/application-gateway
spec:
  tls:
    - hosts:
      - <guestbook.contoso.com>
      secretName: <guestbook-secret-name>
  rules:
  - host: <guestbook.contoso.com>
    http:
      paths:
      - backend:
          service:
            name: frontend
            port:
              number: 80

  2. Deploy ing-guestbook-tls-sni.yaml by running

    kubectl apply -f ing-guestbook-tls-sni.yaml

  3. Check the log of the ingress controller for deployment status.

Now the guestbook application will be available on both HTTP and HTTPS only on the specified host (<guestbook.contoso.com> in this example).