Create an ingress controller in 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. When you use 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. Two applications are then run in the AKS cluster, each of which is accessible over the single IP address.

Note

There are two open source ingress controllers for Kubernetes based on Nginx: one is maintained by the Kubernetes community (kubernetes/ingress-nginx), and one is maintained by NGINX, Inc. (nginxinc/kubernetes-ingress). This article will be using the Kubernetes community ingress controller.

Before you begin

This article uses Helm 3 to install the NGINX ingress controller on a supported version of Kubernetes. Make sure that you're using the latest release of Helm and have access to the ingress-nginx Helm repository. The steps outlined in this article may not be compatible with previous versions of the Helm chart, NGINX ingress controller, or Kubernetes.

This article also requires that you're running the Azure CLI version 2.0.64 or later. Run az --version to find the version. If you need to install or upgrade, see Install Azure CLI.

In addition, this article assumes you have an existing AKS cluster with an integrated Azure Container Registry (ACR). For more information on creating an AKS cluster with an integrated ACR, see Authenticate with Azure Container Registry from Azure Kubernetes Service.

Basic configuration

To create a basic NGINX ingress controller without customizing the defaults, you'll use Helm.

NAMESPACE=ingress-basic

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo update

helm install ingress-nginx ingress-nginx/ingress-nginx \
  --create-namespace \
  --namespace $NAMESPACE \
  --set controller.service.annotations."service\.beta\.kubernetes\.io/azure-load-balancer-health-probe-request-path"=/healthz

The above configuration uses the default configuration for simplicity. You can add parameters for customizing the deployment, for example, --set controller.replicaCount=3. The next section will show a highly customized example of the ingress controller.

Customized configuration

As an alternative to the basic configuration presented in the above section, the next set of steps will show how to deploy a customized ingress controller. You'll have the option of using an internal static IP address, or using a dynamic public IP address.

Import the images used by the Helm chart into your ACR

To control image versions, you'll want to import them into your own Azure Container Registry. The NGINX ingress controller Helm chart relies on three container images. Use az acr import to import those images into your ACR.

REGISTRY_NAME=<REGISTRY_NAME>
SOURCE_REGISTRY=k8s.gcr.io
CONTROLLER_IMAGE=ingress-nginx/controller
CONTROLLER_TAG=v1.2.1
PATCH_IMAGE=ingress-nginx/kube-webhook-certgen
PATCH_TAG=v1.1.1
DEFAULTBACKEND_IMAGE=defaultbackend-amd64
DEFAULTBACKEND_TAG=1.5

az acr import --name $REGISTRY_NAME --source $SOURCE_REGISTRY/$CONTROLLER_IMAGE:$CONTROLLER_TAG --image $CONTROLLER_IMAGE:$CONTROLLER_TAG
az acr import --name $REGISTRY_NAME --source $SOURCE_REGISTRY/$PATCH_IMAGE:$PATCH_TAG --image $PATCH_IMAGE:$PATCH_TAG
az acr import --name $REGISTRY_NAME --source $SOURCE_REGISTRY/$DEFAULTBACKEND_IMAGE:$DEFAULTBACKEND_TAG --image $DEFAULTBACKEND_IMAGE:$DEFAULTBACKEND_TAG

Note

In addition to importing container images into your ACR, you can also import Helm charts into your ACR. For more information, see Push and pull Helm charts to an Azure Container Registry.

Use an internal IP address

By default, an NGINX ingress controller is created with a dynamic public IP address assignment. A common configuration requirement is to use an internal, private network and IP address. This approach allows you to restrict access to your services to internal users, with no external access.

Create a file named internal-ingress.yaml using the following example manifest:

controller:
  service:
    loadBalancerIP: 10.224.0.42
    annotations:
      service.beta.kubernetes.io/azure-load-balancer-internal: "true"

This example assigns 10.224.0.42 to the loadBalancerIP resource. Provide your own internal IP address for use with the ingress controller. Make sure that this IP address isn't already in use within your virtual network. Also, if you're using an existing virtual network and subnet, you must configure your AKS cluster with the correct permissions to manage the virtual network and subnet. For more information, see Use kubenet networking with your own IP address ranges in Azure Kubernetes Service (AKS) or Configure Azure CNI networking in Azure Kubernetes Service (AKS).

When you deploy the nginx-ingress chart with Helm, add the -f internal-ingress.yaml parameter.

# Add the ingress-nginx repository
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx

# Set variable for ACR location to use for pulling images
ACR_URL=<REGISTRY_URL>

# Use Helm to deploy an NGINX ingress controller
helm install ingress-nginx ingress-nginx/ingress-nginx \
    --version 4.1.3 \
    --namespace ingress-basic \
    --create-namespace \
    --set controller.replicaCount=2 \
    --set controller.nodeSelector."kubernetes\.io/os"=linux \
    --set controller.image.registry=$ACR_URL \
    --set controller.image.image=$CONTROLLER_IMAGE \
    --set controller.image.tag=$CONTROLLER_TAG \
    --set controller.image.digest="" \
    --set controller.admissionWebhooks.patch.nodeSelector."kubernetes\.io/os"=linux \
    --set controller.service.annotations."service\.beta\.kubernetes\.io/azure-load-balancer-health-probe-request-path"=/healthz \
    --set controller.admissionWebhooks.patch.image.registry=$ACR_URL \
    --set controller.admissionWebhooks.patch.image.image=$PATCH_IMAGE \
    --set controller.admissionWebhooks.patch.image.tag=$PATCH_TAG \
    --set controller.admissionWebhooks.patch.image.digest="" \
    --set defaultBackend.nodeSelector."kubernetes\.io/os"=linux \
    --set defaultBackend.image.registry=$ACR_URL \
    --set defaultBackend.image.image=$DEFAULTBACKEND_IMAGE \
    --set defaultBackend.image.tag=$DEFAULTBACKEND_TAG \
    --set defaultBackend.image.digest="" \
    -f internal-ingress.yaml

Create an ingress controller

To create the ingress controller, use Helm to install nginx-ingress. The ingress controller needs to be scheduled on a Linux node. Windows Server nodes 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.

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 following example creates a Kubernetes namespace for the ingress resources named ingress-basic and is intended to work within that namespace. Specify a namespace for your own environment as needed. If your AKS cluster isn't Kubernetes role-based access control enabled, add --set rbac.create=false to the Helm commands.

Note

If you would like to enable client source IP preservation for requests to containers in your cluster, add --set controller.service.externalTrafficPolicy=Local to the Helm install command. The client source IP is stored in the request header under X-Forwarded-For. When you're using an ingress controller with client source IP preservation enabled, TLS pass-through won't work.

# Add the ingress-nginx repository
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx

# Set variable for ACR location to use for pulling images
ACR_URL=<REGISTRY_URL>

# Use Helm to deploy an NGINX ingress controller
helm install nginx-ingress ingress-nginx/ingress-nginx \
    --version 4.1.3 \
    --namespace ingress-basic \
    --create-namespace \
    --set controller.replicaCount=2 \
    --set controller.nodeSelector."kubernetes\.io/os"=linux \
    --set controller.image.registry=$ACR_URL \
    --set controller.image.image=$CONTROLLER_IMAGE \
    --set controller.image.tag=$CONTROLLER_TAG \
    --set controller.image.digest="" \
    --set controller.admissionWebhooks.patch.nodeSelector."kubernetes\.io/os"=linux \
    --set controller.service.annotations."service\.beta\.kubernetes\.io/azure-load-balancer-health-probe-request-path"=/healthz \
    --set controller.admissionWebhooks.patch.image.registry=$ACR_URL \
    --set controller.admissionWebhooks.patch.image.image=$PATCH_IMAGE \
    --set controller.admissionWebhooks.patch.image.tag=$PATCH_TAG \
    --set controller.admissionWebhooks.patch.image.digest="" \
    --set defaultBackend.nodeSelector."kubernetes\.io/os"=linux \
    --set defaultBackend.image.registry=$ACR_URL \
    --set defaultBackend.image.image=$DEFAULTBACKEND_IMAGE \
    --set defaultBackend.image.tag=$DEFAULTBACKEND_TAG \
    --set defaultBackend.image.digest=""

Check the load balancer service

Check the load balancer service by using kubectl get services.

kubectl get services --namespace ingress-basic -o wide -w ingress-nginx-controller

When the Kubernetes load balancer service is created for the NGINX ingress controller, an IP address is assigned under EXTERNAL-IP, as shown in the following example output:

NAME                       TYPE           CLUSTER-IP    EXTERNAL-IP     PORT(S)                      AGE   SELECTOR
ingress-nginx-controller   LoadBalancer   10.0.65.205   EXTERNAL-IP     80:30957/TCP,443:32414/TCP   1m   app.kubernetes.io/component=controller,app.kubernetes.io/instance=ingress-nginx,app.kubernetes.io/name=ingress-nginx

No ingress rules have been created yet, so the NGINX ingress controller's default 404 page is displayed if you browse to the external IP address. Ingress rules are configured in the following steps.

Run demo applications

To see the ingress controller in action, run two demo applications in your AKS cluster. In this example, you use kubectl apply to deploy two instances of a simple Hello world application.

Create an aks-helloworld-one.yaml file and copy in the following example YAML:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: aks-helloworld-one  
spec:
  replicas: 1
  selector:
    matchLabels:
      app: aks-helloworld-one
  template:
    metadata:
      labels:
        app: aks-helloworld-one
    spec:
      containers:
      - name: aks-helloworld-one
        image: mcr.microsoft.com/azuredocs/aks-helloworld:v1
        ports:
        - containerPort: 80
        env:
        - name: TITLE
          value: "Welcome to Azure Kubernetes Service (AKS)"
---
apiVersion: v1
kind: Service
metadata:
  name: aks-helloworld-one  
spec:
  type: ClusterIP
  ports:
  - port: 80
  selector:
    app: aks-helloworld-one

Create an aks-helloworld-two.yaml file and copy in the following example YAML:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: aks-helloworld-two  
spec:
  replicas: 1
  selector:
    matchLabels:
      app: aks-helloworld-two
  template:
    metadata:
      labels:
        app: aks-helloworld-two
    spec:
      containers:
      - name: aks-helloworld-two
        image: mcr.microsoft.com/azuredocs/aks-helloworld:v1
        ports:
        - containerPort: 80
        env:
        - name: TITLE
          value: "AKS Ingress Demo"
---
apiVersion: v1
kind: Service
metadata:
  name: aks-helloworld-two  
spec:
  type: ClusterIP
  ports:
  - port: 80
  selector:
    app: aks-helloworld-two

Run the two demo applications using kubectl apply:

kubectl apply -f aks-helloworld-one.yaml --namespace ingress-basic
kubectl apply -f aks-helloworld-two.yaml --namespace ingress-basic

Create an ingress route

Both applications are now running on your Kubernetes cluster. To route traffic to each application, 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 EXTERNAL_IP/hello-world-one is routed to the service named aks-helloworld-one. Traffic to EXTERNAL_IP/hello-world-two is routed to the aks-helloworld-two service. Traffic to EXTERNAL_IP/static is routed to the service named aks-helloworld-one for static assets.

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

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: hello-world-ingress
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "false"
    nginx.ingress.kubernetes.io/use-regex: "true"
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  ingressClassName: nginx
  rules:
  - http:
      paths:
      - path: /hello-world-one(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: aks-helloworld-one
            port:
              number: 80
      - path: /hello-world-two(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: aks-helloworld-two
            port:
              number: 80
      - path: /(.*)
        pathType: Prefix
        backend:
          service:
            name: aks-helloworld-one
            port:
              number: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: hello-world-ingress-static
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "false"
    nginx.ingress.kubernetes.io/rewrite-target: /static/$2
spec:
  ingressClassName: nginx
  rules:
  - http:
      paths:
      - path: /static(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: aks-helloworld-one
            port: 
              number: 80

Create the ingress resource using the kubectl apply command.

kubectl apply -f hello-world-ingress.yaml --namespace ingress-basic

Test the ingress controller

To test the routes for the ingress controller, browse to the two applications. Open a web browser to the IP address of your NGINX ingress controller, such as EXTERNAL_IP. The first demo application is displayed in the web browser, as shown in the following example:

First app running behind the ingress controller

Now add the /hello-world-two path to the IP address, such as EXTERNAL_IP/hello-world-two. The second demo application with the custom title is displayed:

Second app running behind the ingress controller

Test an internal IP address

To test the routes for the ingress controller using an internal IP, create a test pod and attach a terminal session to it:

kubectl run -it --rm aks-ingress-test --image=mcr.microsoft.com/dotnet/runtime-deps:6.0 --namespace ingress-basic

Install curl in the pod using apt-get:

apt-get update && apt-get install -y curl

Now access the address of your Kubernetes ingress controller using curl, such as http://10.224.0.42. Provide your own internal IP address specified when you deployed the ingress controller.

curl -L http://10.224.0.42

No 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 -L http://10.224.0.42

<!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>
[...]

Now add /hello-world-two path to the address, such as http://10.224.0.42/hello-world-two. The second demo application with the custom title is returned, as shown in the following condensed example output:

$ curl -L -k http://10.224.0.42/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, many 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

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 --namespace ingress-basic

NAME                    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                   APP VERSION
nginx-ingress           ingress-basic   1               2020-01-06 19:55:46.358275 -0600 CST    deployed        nginx-ingress-1.27.1    0.26.1  

Uninstall the releases with the helm uninstall command. The following example uninstalls the NGINX ingress deployment.

$ helm uninstall ingress-nginx --namespace ingress-basic

release "ingress-nginx" uninstalled

Next, remove the two sample applications:

kubectl delete -f aks-helloworld-one.yaml --namespace ingress-basic
kubectl delete -f aks-helloworld-two.yaml --namespace ingress-basic

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

kubectl delete -f hello-world-ingress.yaml

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

kubectl delete namespace ingress-basic

Next steps

To configure TLS with your existing ingress components, see Use TLS with an ingress controller.

To configure your AKS cluster to use HTTP application routing, see Enable the HTTP application routing add-on.

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