Kubernetes Ingress Chronicles

Ingress is a powerful Kubernetes resource that helps manage how external HTTP and HTTPS traffic gets routed to services within your cluster. Think of it as a traffic cop for your Kubernetes services, deciding which requests get routed where based on rules you define.

What Exactly is Ingress?

At its core, Ingress allows you to expose your HTTP and HTTPS routes from outside your Kubernetes cluster to the services running inside it. It gives you control over how traffic should be directed based on rules specified in the Ingress resource.

Why Do We Need Ingress?

Without Ingress, managing external access to your services can become cumbersome, especially as your application grows. Ingress simplifies this by allowing you to define routing rules, handle SSL/TLS termination, and even provide load balancing—all in one place.

The Ingress Resource

The following yaml code is how we define Ingress.

#service/networking/minimal-ingress.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: minimal-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx-example
  rules:
  - http:
      paths:
      - path: /testpath
        pathType: Prefix
        backend:
          service:
            name: test
            port:
              number: 80

Breaking It Down:

apiVersion, kind, metadata, and spec: Essential fields for defining an Ingress.
annotations: These provide additional configuration options depending on the Ingress controller. For example, the nginx.ingress.kubernetes.io/rewrite-target annotation helps rewrite URLs before they reach your service.
spec.rules: This section defines the routing rules. For HTTP(S) traffic, you can specify paths and which services should handle requests that match those paths.

Setting Up Ingress on Minikube with NGINX Ingress Controller

Would you be ready to put your knowledge into action? Let’s set up a simple Ingress on Minikube with the NGINX Ingress Controller.

1. Start Minikube

First, ensure you have Minikube installed and running:

minikube start

Enable the Ingress controller

To enable the NGINX Ingress controller, run the following command:
```
 minikube addons enable ingress
```
Verify that the NGINX Ingress controller is running
```
 kubectl get pods -n ingress-nginx
```

The output is similar to:

NAME                                        READY   STATUS      RESTARTS    AGE
ingress-nginx-admission-create-g9g49        0/1     Completed   0          11m
ingress-nginx-admission-patch-rqp78         0/1     Completed   1          11m
ingress-nginx-controller-59b45fb494-26npt   1/1     Running     0          11m

Deploy a hello, world app

Create a Deployment using the following command:

 kubectl create deployment web --image=gcr.io/google-samples/hello-app:1.0

The output should be :

deployment.apps/web created

Verify that the Deployment is in a Ready state:

kubectl get deployment web

The output should be similar to:

NAME   READY   UP-TO-DATE   AVAILABLE   AGE
web    1/1     1            1           53s

Expose the Deployment:

 kubectl expose deployment web --type=NodePort --port=8080

The output should be:

 service/web exposed

Verify the Service is created and is available on a node port:

 kubectl get service web

The output is similar to:

 NAME      TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
 web       NodePort   10.104.133.249   <none>        8080:31637/TCP   12m

Visit the Service via NodePort, using the minikube service command. Follow the instructions for your platform:

For MacOS-

# The command must be run in a separate terminal.
minikube service web --url

Output is similar to:

http://127.0.0.1:62445
! Because you are using a Docker driver on Darwin, the terminal needs to be open to run it.

From a different terminal, invoke the URL obtained in the output of the previous step:

curl http://127.0.0.1:62445

Wrapping Up

In this guide, we’ve explored how Ingress can simplify managing external access to your Kubernetes services. By setting up Ingress with Minikube and the NGINX Ingress Controller, you’ve seen how to route traffic and effectively expose services. Keep experimenting and diving deeper to master Kubernetes Ingress and enhance your cloud-native skills!