# Kubernetes LoadBalancer


## What is Kubernetes LoadBalancer?

A LoadBalancer service is the standard way to expose a service to the outside. On cloud, this will spin up a Network Load Balancer that will give you a single IP address that will forward all traffic to your service.


If your Kubernetes cluster environment is on any cloud provider like google cloud, Azure, or AWS, then if you use the type load balancer, you will get an external IP from this provider on behalf of you. so you can access your application using the external IP provided by the provider that will forward the request to the pods. But is chargeable.

if you are using On-Premises BareMetal Kubernetes Environment then you need to use MetalLB for getting the load balancer external IP 

**A pure software solution: MetalLB**

MetalLB provides a network load-balancer implementation for Kubernetes clusters that do not run on a supported cloud provider, effectively allowing the usage of LoadBalancer Services within any cluster.

This section demonstrates how to use the Layer 2 configuration mode of MetalLB together with the NGINX Ingress controller in a Kubernetes cluster that has publicly accessible nodes. In this mode, one node attracts all the traffic for the ingress-nginx Service IP. 


![image.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1652978912620/1ZocsphCp.png align="left")


**Installation**

Helm Add Repository and Update
We will add the helm repository and then make sure that all of our repositories are up to date.

```
helm repo add metallb https://metallb.github.io/metallb
helm repo update
``` 

**Basic configuration **

```
$ cat values.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: default
      protocol: layer2
      addresses:
        - 192.168.100.120-192.168.100.130
``` 

```
kubectl apply -f  values.yaml
``` 

**Load Balancer workflow diagram **

![Loadbalancer.jpg](https://cdn.hashnode.com/res/hashnode/image/upload/v1652980245214/Pan6qDRqg.jpg align="left")

First, we need to create a deployment 

```
root@Kubernet-Master:~# cat deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:    #label name should be common in load balancer service  
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

root@Kubernet-Master:~#

``` 

```
kubectl apply -f  deployment.yaml
``` 
For checking the deployment status 

```
kubectl get deployment 
``` 

![image.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1652980529361/wPUj6DQ76.png align="left")

Load balancer Manifest file 
```
root@Kubernet-Master:~# cat loadbalancer.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: LoadBalancer
status:
  loadBalancer:

``` 
Apply the configuration 

```
kubectl apply -f loadbalancer.yaml
``` 

**For checking the service output **
```
kubectl get svc 
``` 

![image.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1652980785596/qMIUghM5W.png align="left")


```
http://192.168.100.120
``` 


![image.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1652981443787/zQ_brvzQt.png align="left")

Hope you have got an idea about Kubernetes Load Balancer and why it is needed

**Thank you !!!**