Kubernetes is a powerful tool. It can help you manage complex applications and provide you with the ability to easily automate tasks involved in managing them. In this course, we will start exploring Kubernetes from a beginner's standpoint. We will discuss what Kubernetes is and what it does, and we will work with some of the basic functionality of Kubernetes hands-on. We will build a simple Kubernetes cluster. We will also deploy a sample microservice application to the cluster in order to explore how Kubernetes can help easily manage such applications.

A Practical Guide to Kubernetes

# Defining an Ingress Resource

We'll try to make our `go-demo-2-api` Service available through the port `80`. We'll do that by defining an Ingress resource with the rule to forward all requests with the path starting with `/demo` to the Service `go-demo-2-api`.

## Looking into the Definition
Let's take a look at the Ingress' YAML definition.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: go-demo-2
  annotations:
    kubernetes.io/ingress.class: "nginx"
    ingress.kubernetes.io/ssl-redirect: "false"
    nginx.ingress.kubernetes.io/ssl-redirect: "false"
spec:
  rules:
  - http:
      paths:
      - path: /demo
        backend:
          serviceName: go-demo-2-api
          servicePort: 8080


* **Line 5:** This time, `metadata` contains a field we haven't used before. The `annotations` section allows us to provide additional information to the Ingress Controller. As you'll see soon, Ingress API specification is concise and limited. That is done on purpose. The specification API defines only the fields that are mandatory for all Ingress Controllers. All the additional info an Ingress Controller needs is specified through `annotations`. That way, the community behind the Controllers can progress at great speed, while still providing basic general compatibility and standards.

>ℹ️  The list of general annotations and the Controllers that support them can be found in the [Ingress Annotations](https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/annotations.md) page. For those specific to the [NGINX Ingress Controller](https://github.com/kubernetes/ingress-nginx/blob/master/README.md), please visit the [NGINX Annotations](https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/annotations.md) page, and for those specific to GCE Ingress, visit the [ingress-gce](https://github.com/kubernetes/ingress-gce) page.

>⚠️  You'll notice that documentation uses `nginx.ingress.kubernetes.io/` annotation prefixes. That is a relatively recent change that, at the time of this writing, applies to the beta versions of the Controller. We're combining it with `ingress.kubernetes.io/` prefixes so that the definitions work in all Kubernetes versions.

* **Line 8:** We specified only one annotation. `nginx.ingress.kubernetes.io/ssl-redirect: "false"` tells the Controller that we do NOT want to redirect all HTTP requests to HTTPS. We're forced to do so since we do not have SSL certificates for the exercises that follow.

Now that we shed some light on the `metadata` and `annotations`, we can move to the `ingress` specification.

* **Line 9-16:** We specified a set of `rules` in the `spec` section. They are used to configure Ingress resource. For now, our rule is based on `http` with a single `path` and a `backend`. All the requests with the `path` starting with `/demo` will be forwarded to the service `go-demo-2-api` on the port `8080`.

# Creating the Resource
Now that we had a short tour around some of the Ingress configuration options, we can proceed and create the resource.

In this lesson, first, we will look into the definition of an Ingress resource and then create it.

Creating Ingress Resources Based on Paths

Defining an Ingress Resource

Looking into the Definition