Expose Your Application To The Internet With A Loa

To expose an application to the Internet, you need to use a kubernetes service.
A kubernetes service is a loadbalancer that directs traffic from the Internet to the Kubernetes Pods.
A loadbalancer service has a public and static IP address.
The static IP is important, as pods and their IPs change frequently.
- The service IP needs to remain the same.
Example yaml manifest for a service: ``` — apiVersion: v1 kind: Service metadata: name: demo-service namespace: development spec: selector: app: pod-info ports:
- port: 80 targetPort: 3000 type: LoadBalancer ```
Very important part of the above yaml is the:
```
selector:
  app: pod-info
```
That sends traffic to any pods with the label pod-info.
All the pods deployed in the deployment.yaml file also need the label pod-info.
- If they do not have this, they will not be able to direct traffic to the pods.
In the service.yaml file, we set the port to 80, so that the port does not need to be typed in the URL: ``` ports:
- port: 80 ```
The service however is directing traffic to port 3000 in the container:
```
targetPort: 3000
```
Finally, we are specifying that the service type is a loadbalancer:
```
type: LoadBalancer
```
A LoadBalancer is one type of Kubernetes service. There are in fact 3 types of services:
- LoadBalancer
- NodePort
- ClusterIP

Another command is minikube tunnel. This shows an output similar to:

Status:	
  machine: minikube
  pid: 69570
  route: 10.96.0.0/12 -> 192.168.49.2
  minikube: Running
  services: []
  errors: 
      minikube: no errors
      router: no errors
      loadbalancer emulator: no errors

This allows minikube to access the external network. Exposes the application to the Internet.
- ctrl + c to stop the service.

We create the service with:

kubectl apply -f ./Ex_Files_Learning_Kubernetes/Exercise\ Files/04_01/service.yaml

Running kubectl get services -n development, then shows the internal IP as CLUSTER-IP and the external IP as EXTERNAL-IP
If you create a Kubernetes cluster on AWS, Azure, GCP etc, they provide you with a public IP address.
For example, copy and paste the external IP into your browser and you will see the JSON object: 10.101.236.59 like so:
```
{"pod_name":"pod-info-deployment-7587d5cc86-vk6br","pod_namespace":"development","pod_ip":"10.244.0.9"}
```