Spring Boot Application with DATA REST + MYSQL deployed on Kubernetes

This application is showcases the following

• Create a Basic Spring Boot Application
• Create a Repository and Entity for Student
• Create RESTful CRUD operations for Student using Spring DATA REST
• Use MySQL as database
• Build and Test application locally
• Create a docker image and push it to docker hub.
• Deploy a mysql database in Kubernetes
• Deploy the application in Kubernetes and connect to the MySQL database already deployed

Building the application

• Download the application code from github
• Ensure that docker, gradle and Java 11 are already installed
• Ensure that MySQL Database is already installed
• Go to the application git folder
• Open the application.properties and ensure that For Testing locally section is uncommented and For Deployment in Kubernetes section is commented
• Execute the following command "gradlew clean build" in windows or "./gradlew clean build" in linux
• To start the application excute the gradle bootRun task. It would open the application at "http://localhost:8080"
• All the crud operations could be done at "http://localhost:8080/student"

Dockerizing the application

• Stop the application by terminating the gradle bootRun task if it is running
• Open the application.properties and ensure that For Testing locally section is commented and For Deployment in Kubernetes section is uncommented
• Execute "gradlew clean build -x test"
• Dockerfile is already available for docker build
• Execute "docker build -t [your-docker-user-name]/mysql-app:v1 ."
• Ensure that the image got created by executing "docker images"
• Push the image to docker hub by executing "docker push [your-docker-user-name]/mysql-app:v1"

Deploying in Kubernetes

• Use any Kubernetes deployment. My choice is Minikube
• Start Minikube
• Create a directory called "/mnt/data" for persistent volume
• Execute the following commands one after another in sequence
  • kubectl apply -f deployments/mysql-pv.yaml
  • kubectl apply -f deployments/mysql-pvc.yaml
  • kubectl apply -f deployments/mysql-deployment.yaml
  • kubectl apply -f deployments/mysql-service.yaml

All these would ensure that Persistent Volume, MySQL deployment are created. The MySQL deployment is also exposed as a service called mysql which we are referring in our SPRING_DATASOURCE_URL section without any port

• To access the mysql service execute the command mentioned in the mysql-client.txt file under deployments folder
• To deploy the application first open the mysql-app-deployment.yaml and replace adityapratapbhuyan/mysqlapp:no-port with docker push [your-docker-user-name]/mysql-app:v1
• Execute "kubectl apply -f deployments/mysql-app-deployment.yaml". It would take around 2-3 minutes for the first time to download the image and deploy. Ensure the image started successfully by executing "kubectl get deploy"
• Once the Deployment for the app is running, execute the below command to expose the deployment as a service kubectl -f deployments/mysql-app-service.yaml
• Once the service is created the service could be accessed by executing "minikube service mysql-app". It would open the service endpoint on the browser. Then the testing could be done on the url opened in the browser.