Basic usage - host based routing ¶

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ingress-nginx can be used for many use cases, inside various cloud providers and supports a lot of configurations. In this section you can find a common usage scenario where a single load balancer powered by ingress-nginx will route traffic to 2 different HTTP backend services based on the host name.

First of all follow the instructions to install ingress-nginx. Then imagine that you need to expose 2 HTTP services already installed, myServiceA, myServiceB, and configured as type: ClusterIP.

Let's say that you want to expose the first at myServiceA.foo.org and the second at myServiceB.foo.org.

If the cluster version is < 1.19, you can create two ingress resources like this:

`apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: name: ingress-myservicea spec: ingressClassName: nginx rules:

  • host: myservicea.foo.org http: paths:
    • path: / backend: serviceName: myservicea servicePort: 80

apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: name: ingress-myserviceb annotations: # use the shared ingress-nginx kubernetes.io/ingress.class: "nginx" spec: rules:

  • host: myserviceb.foo.org http: paths:
    • path: / backend: serviceName: myserviceb servicePort: 80`

If the cluster uses Kubernetes version >= 1.19.x, then its suggested to create 2 ingress resources, using yaml examples shown below. These examples are in conformity with the networking.kubernetes.io/v1 api.

`apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: ingress-myservicea spec: rules:

  • host: myservicea.foo.org http: paths:
    • path: / pathType: Prefix backend: service: name: myservicea port: number: 80 ingressClassName: nginx

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: ingress-myserviceb spec: rules:

  • host: myserviceb.foo.org http: paths:
    • path: / pathType: Prefix backend: service: name: myserviceb port: number: 80 ingressClassName: nginx`

When you apply this yaml, 2 ingress resources will be created managed by the ingress-nginx instance. Nginx is configured to automatically discover all ingress with the kubernetes.io/ingress.class: "nginx" annotation or where ingressClassName: nginx is present. Please note that the ingress resource should be placed inside the same namespace of the backend resource.

On many cloud providers ingress-nginx will also create the corresponding Load Balancer resource. All you have to do is get the external IP and add a DNS A record inside your DNS provider that point myservicea.foo.org and myserviceb.foo.org to the nginx external IP. Get the external IP by running:

kubectl get services -n ingress-nginx

To test inside minikube refer to this documentation: Set up Ingress on Minikube with the NGINX Ingress Controller

リンク
https://kubernetes.github.io/ingress-nginx/user-guide/basic-usage/
要約する
The article discusses using ingress-nginx to route traffic to two different HTTP backend services based on hostnames. It outlines the installation of ingress-nginx and provides a scenario where two services, `myServiceA` and `myServiceB`, configured as `ClusterIP`, need to be exposed at `myServiceA.foo.org` and `myServiceB.foo.org`. For Kubernetes versions below 1.19, it suggests creating two ingress resources using the `v1beta1` API. For versions 1.19 and above, it recommends using the `v1` API with updated YAML examples. The ingress resources are configured to route traffic to the respective services, and the ingress-nginx instance manages them. The article notes that ingress-nginx may also create a Load Balancer resource on various cloud providers, and users need to set up DNS `A records` pointing to the external IP of the Load Balancer. To retrieve the external IP, the command `kubectl get services -n ingress-nginx` is provided. Additionally, it references documentation for setting up ingress on Minikube with the NGINX Ingress Controller.