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Pavan Belagatti
Pavan Belagatti

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Kubernetes Service Types Tutorial

We hope you are here to understand how Kubernetes services work and what are the different service types available. While most cloud-native deployments happen with Kubernetes, it becomes necessary to know these service types, when to use what type, and how they work. Today, we will look at the different service types available and how they work in practice.

Below is my other article where I have explained in detail about each service type.

Prerequisites

  • Docker Desktop installed and enabled. Install it from this official link
  • Minikube installed and running on your computer. It is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Get it from this official link

Let’s Get Started:

Let’s create an NGINX web-server deployment with a pod that accepts the traffic to its port 80.

kubectl create deployment nginx --image=nginx
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You should see the below output on your terminal,

deployment.apps/nginx created

Now, check if the NGINX is running with the command,

kubectl get deploy nginx
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The output you should see on your terminal is below,

kubectl command

Find the exact name of the pod so we can do port forwarding to make it accept the traffic from port 80

Use the following command to find the pod’s name.

kubectl get pod
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Then do port forwarding with the following command

kubectl port-forward <pod name> 8080:80
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You should see the output similar to as shown below,

Forwarding from 127.0.0.1:8080 -> 80
Forwarding from [::1]:8080 -> 80
Handling connection for 8080

Check your localhost:8080, you should see the NGINX screen.

ClusterIP:

Let’s create a Kubernetes manifest yaml file with type ClusterIP.

Name this file as nginx-svc.yaml

---
apiVersion: v1
kind: Service
metadata:
  name: "nginx-service"
  namespace: "default"
spec:
  ports:
    - port: 80
  type: ClusterIP
  selector:
    app: "nginx"
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Create the NGINX service with the following command,

kubectl apply -f nginx-svc.yaml
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The output should be as below,

service/nginx-service created

Now, check the service via kubectl command,

kubectl get svc nginx-service
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The output should be as below,
output

Since ClusterIP type is only accessible by the internal pods, we will use kubectl proxy command to do port forward and access our NGINX.

kubectl proxy --port=8080
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The output should be as below on your terminal,

Starting to serve on 127.0.0.1:8080

NodePort:

Update the Kubernetes manifest file as below,

---
apiVersion: v1
kind: Service
metadata:
  name: "nginx-service"
  namespace: "default"
spec:
  ports:
    - port: 80
      nodePort: 30001
  type: NodePort
  selector:
    app: "nginx"
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Now, apply the following command and update the service,

kubectl apply -f nginx-svc.yaml
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The output is as below,

service/nginx-service configured

Now, check this service and you should see the type,

kubectl get svc nginx-service
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Below is the output,

nodeport

Let’s try to access this externally, for that we need to use the describe service command,

kubectl describe service nginx-service
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The output on your terminal should be as below,

nodeport1

I am using Minikube to create a cluster and Minikube has a command for the NodePort access,

minikube service --url <service-name>
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I used minikube service --url nginx-service and the output was as expected, the external URL to access our NGINX.

nginx service

Go to the terminal and the http://127.0.0.1:63907, we should be seeing our NGINX screen.

nginx service

LoadBalancer:

Update the Kubernetes manifest file again to specify the LoadBalancer type.

---
apiVersion: v1
kind: Service
metadata:
  name: "nginx-service"
  namespace: "default"
spec:
  ports:
    - port: 80
  type: LoadBalancer
  selector:
    app: "nginx"
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Now, apply the following command and update the service,

kubectl apply -f nginx-svc.yaml
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The output is as below,

service/nginx-service configured

Now, check this service and you should see the type,

kubectl get svc nginx-service
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Note: The external IP will be shown pending as we are using Minikube and hence we need to use the following command to get the external IP address.

minikube tunnel
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Now, let’s access the service with the command,

minikube service nginx-service
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The output is as below,

tunnel

When you access your http://127.0.0.1:64711/ local, you should see the NGINX screen.

Ingress - with NGINX ingress as an example

The full tutorial on Setting up Ingress on Minikube with the NGINX Ingress Controller is clearly shown in the official Kubernetes documentation so we will not repeat the same thing again.

Or, you can follow this simple tutorial of Ingress.

You can start the Minikube with the command,

minikube start
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It configures a bunch of resources required to run Minikube.

Then, the next step is to enable the ingress-controller add-on available with minikube from the following command,

minikube addons enable ingress
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And the end output on your terminal should be as below,

The 'ingress' addon is enabled

Verify that ingress has been enabled with the command,

kubectl get pods -n ingress-nginx
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The output should be as below,

ingress

Let’s create a deployment example with the following command,

kubectl create deployment nginx --image=nginx
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The output should be as shown below,
deployment.apps/nginx created

You can verify this deployment with the following command,
kubectl get deployments

You should see the nginx deployment as output.

nginx deployment

Now, let’s expose this deployment with a service, by binding the port 80.

kubectl expose deployment nginx --type=NodePort --port=80
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You should see the service exposed message on the terminal.

service/nginx exposed

You can see the details about this service created with the command,

kubectl get service nginx
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The output you should see is as below,

service

Now, you can easily access the NGINX service on your local machine with the following command,

minikube service nginx --url
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The output you should see is as below,

Ingress minikube url

Access the url http://127.0.0.1:57460 and you should be able to see the NGINX screen.

nginx page

Kubernetes is a powerful tool for automating and managing your IT infrastructure. It gives you the ability to group related parts of your infrastructure, giving them their own β€œnode” in the cluster, making them easier to manage, monitor, and update.

As Kubernetes adoption is skyrocketing, it has become a must-know platform for developers and enterprises to be competitive in the cloud-native space.

The Harness Platform is built with all the capabilities to supercharge your Kubernetes deployments with ease. Harness has an intuitive dashboard where you can easily configure your deployment stage, target infrastructure, and execution strategy.

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