Hands-On Guide

Deploying a Java Spring Boot Application on Kubernetes with MySQL.

WORK FLOW

lets divide the flow into small steps:

1. Set up the cloud server

2. Install the dependencies

3. Set up Mini-Kube

4. Clone the Repository

5. Configure the database required.

6. Build the project

7. Create the Docker images

8. Push the images to Dockerhub

9. Run the manifest files

10. Do port forwarding

11. Check JSON data to be hit on Postman

12. Add some data to the database using postman

13. Check the Database if the entries are visible

14. Check Mini-Kube dashboard

Source Code :

GitHub - SurendarSv/SpringBootOnK8s

Contribute to SurendarSv/SpringBootOnK8s development by creating an account on GitHub.

github.com

STEPS :

create a server t2.medium

Connect through SSH:

Update the packages and package caches. Use commands :

#sudo su
#yum update -y

Install docker. Use commands :

#yum install docker

#systemctl enable docker

#systemctl start docker

#systemctl status docker

#docker — version

Check Docker version

Start docker and check status docker

Conntrack : is a short for Connection Tracking, is a crucial component in Kubernetes networking that is required for reliable communication between containers and services. It is responsible for tracking network connections and their states, allowing the Kubernetes networking stack to function properly.

Conntrack is needed for minikube.

Install Conntrack

#yum install conntrack -y

Install git. Use command :

#yum install git

#git --version

To download the latest version of Minikube for the Linux platform.

#curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64

#ls -lrta

minikube has been downloaded.

Install minikube. Use command :

#sudo install minikube-linux-amd64 /usr/local/bin/minikube

Start minikube:

minikube is platform which gives k8s

#/usr/local/bin/minikube start --force --driver=docker

Why do we need docker driver?

Kubernetes is a platform which is running on docker. Docker is helping Kubernetes to run.

Check minikube version

#/usr/local/bin/minikube version

Install kubectl:

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"

Giving permissions to kubectl

sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl

Check version

/usr/local/bin/kubectl version

Install git

Clone the repo:

yum install git -y
git --version
cd /opt
git clone https://github.com/SurendarSv/SpringBootOnK8s.git

DB installation / make the DB up:

/usr/local/bin/kubectl get pods
/usr/local/bin/kubectl create -f db-deployment.yaml

To create the persistent database and other services.

we have change dir to /usr/local/bin

Because minikube has been installed there.

cd /usr/local/bin

Check pods:

kubectl get pods

Check database i.e going inside the container

/usr/local/bin/kubectl exec -it <POD_NAME>/bin/bash
IN MY CASE
/usr/local/bin/kubectl exec -it mysql-f759455cd-n5gw6 /bin/bash

Enter the DB,password is : root

mysql -u root -p

DB created from the deployment file.DB name : singamlabs

now exit the pod.

Install maven now and check version:

yum install maven -y
mvn -v

No images are available.

docker images

Create the docker image now.

docker build -t surendar24/springboot-crud-k8s:1.0 .

Login to docker hub:

docker login

Push the image to docker hub:

docker image push surendar24/springboot-crud-k8s:1.0 .

IMAGE is pushed to docker hub:

execute the app. deploy.yaml file.

/usr/local/bin/kubectl apply -f app-deployment.yaml

Check pods

/usr/local/bin/kubectl get pods

4 pods -> 3 are replicas

Check svc available.

/usr/local/bin/kubectl get svc

minikube ip

/usr/local/bin/minikube ip

Why multiple pods/pod replicas?

Replicas are being created so that the traffic will get distributed.

PORT-FORWARDING

Port forwarding is a networking technique used to redirect network traffic from one port on a host to another port on a different host or the same host. In the context of Kubernetes, port forwarding allows you to access services running inside a Kubernetes cluster from your local machine or another remote host.

Put port forward.

/usr/local/bin/kubectl port-forward --address 0.0.0.0 svc/springboot-crud-svc 8080:8080 &

Update it.

Now go back to postman again. And add a entry.

POSTMAN

POST method :

GET method :

/usr/local/bin/kubectl exec -it mysql-f759455cd-n5gw6 /bin/bash

The Changes can be observed instanly.

Exit mySQL

Open the Dashboard of K8S.

Open a new terminal of your server and then perform this command.

Inside EC2 our minikube is running so we are setting a proxy for all the local address.

/usr/local/bin/kubectl proxy --address='0.0.0.0' --accept-hosts='^*$'

The proxy server is started on port 8001.

Open another terminal:

/usr/local/bin/minikube dashboard

change the IP address with your EC2 server IP address and port 8081.
In my case:
http://20.234.84.191:8001/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/

Hence Deployment a Java Spring Boot Application on Kubernetes with MySQL.

Detailed Project OverView:

youtube.com/watch?v=tfoOBn_hcgc&list=PL..

Credits: Praveen Singampalli

Thanks for reading :)