Create an HTTPS ingress controller and use your own TLS certificates on Azure Kubernetes Service (AKS)

An ingress controller is a piece of software that provides reverse proxy, configurable traffic routing, and TLS termination for Kubernetes services. Kubernetes ingress resources are used to configure the ingress rules and routes for individual Kubernetes services. Using an ingress controller and ingress rules, a single IP address can be used to route traffic to multiple services in a Kubernetes cluster.

This article shows you how to deploy the NGINX ingress controller in an Azure Kubernetes Service (AKS) cluster. You generate your own certificates, and create a Kubernetes secret for use with the ingress route. Finally, two applications are run in the AKS cluster, each of which is accessible over a single IP address.

You can also:

Before you begin

This article uses Helm to install the NGINX ingress controller and a sample web app. You need to have Helm initialized within your AKS cluster and using a service account for Tiller. Make sure that you are using the latest release of Helm. For upgrade instructions, see the Helm install docs. For more information on configuring and using Helm, see Install applications with Helm in Azure Kubernetes Service (AKS).

This article also requires that you are running the Azure CLI version 2.0.61 or later. Run az --version to find the version. If you need to install or upgrade, see Install Azure CLI.

Create an ingress controller

To create the ingress controller, use Helm to install nginx-ingress. For added redundancy, two replicas of the NGINX ingress controllers are deployed with the --set controller.replicaCount parameter. To fully benefit from running replicas of the ingress controller, make sure there's more than one node in your AKS cluster.

The ingress controller also needs to be scheduled on a Linux node. Windows Server nodes (currently in preview in AKS) shouldn't run the ingress controller. A node selector is specified using the --set nodeSelector parameter to tell the Kubernetes scheduler to run the NGINX ingress controller on a Linux-based node.

Tip

The following example creates a Kubernetes namespace for the ingress resources named ingress-basic. Specify a namespace for your own environment as needed. If your AKS cluster is not RBAC enabled, add --set rbac.create=false to the Helm commands.

# Create a namespace for your ingress resources
kubectl create namespace ingress-basic

# Use Helm to deploy an NGINX ingress controller
helm install stable/nginx-ingress \
    --namespace ingress-basic \
    --set controller.replicaCount=2 \
    --set nodeSelector."beta.kubernetes.io/os"=linux

During the installation, an Azure public IP address is created for the ingress controller. This public IP address is static for the life-span of the ingress controller. If you delete the ingress controller, the public IP address assignment is lost. If you then create an additional ingress controller, a new public IP address is assigned. If you wish to retain the use of the public IP address, you can instead create an ingress controller with a static public IP address.

To get the public IP address, use the kubectl get service command. It takes a few minutes for the IP address to be assigned to the service.

$ kubectl get service -l app=nginx-ingress --namespace ingress-basic

NAME                                          TYPE           CLUSTER-IP    EXTERNAL-IP    PORT(S)                      AGE
virulent-seal-nginx-ingress-controller        LoadBalancer   10.0.48.240   40.87.46.190   80:31159/TCP,443:30657/TCP   7m
virulent-seal-nginx-ingress-default-backend   ClusterIP      10.0.50.5     <none>         80/TCP                       7m

Make a note of this public IP address, as it's used in the last step to test the deployment.

No ingress rules have been created yet. If you browse to the public IP address, the NGINX ingress controller's default 404 page is displayed.

Generate TLS certificates

For this article, let's generate a self-signed certificate with openssl. For production use, you should request a trusted, signed certificate through a provider or your own certificate authority (CA). In the next step, you generate a Kubernetes Secret using the TLS certificate and private key generated by OpenSSL.

The following example generates a 2048-bit RSA X509 certificate valid for 365 days named aks-ingress-tls.crt. The private key file is named aks-ingress-tls.key. A Kubernetes TLS secret requires both of these files.

This article works with the demo.azure.com subject common name and doesn't need to be changed. For production use, specify your own organizational values for the -subj parameter:

openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
    -out aks-ingress-tls.crt \
    -keyout aks-ingress-tls.key \
    -subj "/CN=demo.azure.com/O=aks-ingress-tls"

Create Kubernetes secret for the TLS certificate

To allow Kubernetes to use the TLS certificate and private key for the ingress controller, you create and use a Secret. The secret is defined once, and uses the certificate and key file created in the previous step. You then reference this secret when you define ingress routes.

The following example creates a Secret name aks-ingress-tls:

kubectl create secret tls aks-ingress-tls \
    --namespace ingress-basic \
    --key aks-ingress-tls.key \
    --cert aks-ingress-tls.crt

Run demo applications

An ingress controller and a Secret with your certificate have been configured. Now let's run two demo applications in your AKS cluster. In this example, Helm is used to deploy two instances of a simple 'Hello world' application.

Before you can install the sample Helm charts, add the Azure samples repository to your Helm environment as follows:

helm repo add azure-samples https://azure-samples.github.io/helm-charts/

Create the first demo application from a Helm chart with the following command:

helm install azure-samples/aks-helloworld --namespace ingress-basic

Now install a second instance of the demo application. For the second instance, you specify a new title so that the two applications are visually distinct. You also specify a unique service name:

helm install azure-samples/aks-helloworld \
    --namespace ingress-basic \
    --set title="AKS Ingress Demo" \
    --set serviceName="ingress-demo"

Create an ingress route

Both applications are now running on your Kubernetes cluster, however they're configured with a service of type ClusterIP. As such, the applications aren't accessible from the internet. To make them publicly available, create a Kubernetes ingress resource. The ingress resource configures the rules that route traffic to one of the two applications.

In the following example, traffic to the address https://demo.azure.com/ is routed to the service named aks-helloworld. Traffic to the address https://demo.azure.com/hello-world-two is routed to the ingress-demo service. For this article, you don't need to change those demo host names. For production use, provide the names specified as part of the certificate request and generation process.

Tip

If the host name specified during the certificate request process, the CN name, doesn't match the host defined in your ingress route, you ingress controller displays a Kubernetes Ingress Controller Fake Certificate. Make sure your certificate and ingress route host names match.

The tls section tells the ingress route to use the Secret named aks-ingress-tls for the host demo.azure.com. Again, for production use, specify your own host address.

Create a file named hello-world-ingress.yaml and copy in the following example YAML.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: hello-world-ingress
  namespace: ingress-basic
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  tls:
  - hosts:
    - demo.azure.com
    secretName: aks-ingress-tls
  rules:
  - host: demo.azure.com
    http:
      paths:
      - path: /
        backend:
          serviceName: aks-helloworld
          servicePort: 80
      - path: /hello-world-two
        backend:
          serviceName: ingress-demo
          servicePort: 80

Create the ingress resource using the kubectl apply -f hello-world-ingress.yaml command.

$ kubectl apply -f hello-world-ingress.yaml

ingress.extensions/hello-world-ingress created

Test the ingress configuration

To test the certificates with our fake demo.azure.com host, use curl and specify the --resolve parameter. This parameter lets you map the demo.azure.com name to the public IP address of your ingress controller. Specify the public IP address of your own ingress controller, as shown in the following example:

curl -v -k --resolve demo.azure.com:443:40.87.46.190 https://demo.azure.com

No additional path was provided with the address, so the ingress controller defaults to the / route. The first demo application is returned, as shown in the following condensed example output:

$ curl -v -k --resolve demo.azure.com:443:40.87.46.190 https://demo.azure.com

[...]
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <link rel="stylesheet" type="text/css" href="/static/default.css">
    <title>Welcome to Azure Kubernetes Service (AKS)</title>
[...]

The -v parameter in our curl command outputs verbose information, including the TLS certificate received. Half-way through your curl output, you can verify that your own TLS certificate was used. The -k parameter continues loading the page even though we're using a self-signed certificate. The following example shows that the issuer: CN=demo.azure.com; O=aks-ingress-tls certificate was used:

[...]
* Server certificate:
*  subject: CN=demo.azure.com; O=aks-ingress-tls
*  start date: Oct 22 22:13:54 2018 GMT
*  expire date: Oct 22 22:13:54 2019 GMT
*  issuer: CN=demo.azure.com; O=aks-ingress-tls
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
[...]

Now add /hello-world-two path to the address, such as https://demo.azure.com/hello-world-two. The second demo application with the custom title is returned, as shown in the following condensed example output:

$ curl -v -k --resolve demo.azure.com:443:137.117.36.18 https://demo.azure.com/hello-world-two

[...]
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <link rel="stylesheet" type="text/css" href="/static/default.css">
    <title>AKS Ingress Demo</title>
[...]

Clean up resources

This article used Helm to install the ingress components and sample apps. When you deploy a Helm chart, a number of Kubernetes resources are created. These resources include pods, deployments, and services. To clean up these resources, you can either delete the entire sample namespace, or the individual resources.

Delete the sample namespace and all resources

To delete the entire sample namespace, use the kubectl delete command and specify your namespace name. All the resources in the namespace are deleted.

kubectl delete namespace ingress-basic

Then, remove the Helm repo for the AKS hello world app:

helm repo remove azure-samples

Delete resources individually

Alternatively, a more granular approach is to delete the individual resources created. List the Helm releases with the helm list command. Look for charts named nginx-ingress and aks-helloworld, as shown in the following example output:

$ helm list

NAME           	REVISION	UPDATED                 	STATUS  	CHART               	APP VERSION	NAMESPACE
virulent-seal  	1       	Tue Oct 23 16:37:24 2018	DEPLOYED	nginx-ingress-0.22.1	0.15.0     	kube-system
billowing-guppy	1       	Tue Oct 23 16:41:38 2018	DEPLOYED	aks-helloworld-0.1.0	           	default
listless-quokka	1       	Tue Oct 23 16:41:30 2018	DEPLOYED	aks-helloworld-0.1.0	           	default

Delete the releases with the helm delete command. The following example deletes the NGINX ingress deployment and the two sample AKS hello world apps.

$ helm delete virulent-seal billowing-guppy listless-quokka

release "virulent-seal" deleted
release "billowing-guppy" deleted
release "listless-quokka" deleted

Next, remove the Helm repo for the AKS hello world app:

helm repo remove azure-samples

Remove the ingress route that directed traffic to the sample apps:

kubectl delete -f hello-world-ingress.yaml

Delete the certificate Secret:

kubectl delete secret aks-ingress-tls

Finally, you can delete the itself namespace. Use the kubectl delete command and specify your namespace name:

kubectl delete namespace ingress-basic

Next steps

This article included some external components to AKS. To learn more about these components, see the following project pages:

You can also: