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How to Build and Deploy a Spring Boot Java application with Docker & Kubernetes


Pre-requisites:
Install Docker client/server
Install K8s cluster.

In the K8s Master Node.

git clone https://github.com/spring-guides/gs-spring-boot-docker


cd gs-spring-boot-docker/complete

./mvnw install -e -X # This will create a .jar file in the newely created target directory.

sudo docker build -t image-sb1 -f Dockerfile .

sudo docker images
sudo docker tag image-sb1 trow.kube-public:31000/myrepo # Tag the new image with your private registry (Optional)
sudo docker push trow.kube-public:31000/myrepo  # Push the new image to your local private registry (Optional)

kubectl run image-sb --image=trow.kube-public:31000/myrepo --port=8080

kubectl expose deployment/image-sb --type="NodePort" --port 8080

Testing:
----------------------------------------------------------------------
ubuntu@namenode:~$ kubectl get svc
NAME          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
kubernetes    ClusterIP   10.96.0.1               443/TCP          2d2h
image-sb   NodePort    10.102.38.118           8080:30148/TCP   18m


ubuntu@namenode:~$ curl 10.102.38.118:8080
Hello Docker World

----------------------------------------------------------------------

ubuntu@namenode:~$ kubectl get pods
NAME                           READY   STATUS    RESTARTS   AGE
image-sb-76448df777-mxwqq   1/1     Running   0          72m

The below command will get you inside the k8s pod image-sb-76448df777-mxwqq

ubuntu@namenode:~$ kubectl exec -ti image-sb-76448df777-mxwqq sh
#  wget localhost:8080
Connecting to localhost:8080 (127.0.0.1:8080)
index.html           100% |************************************************************************************************************************|    18  0:00:00 ETA
#
----------------------------------------------------------------------

If you are inside an aws Ec2 instance then whitelist your Public Ip for the NodePort 30148 in your k8s master node security group.


Take the url :30148 in the browser and you will see "Hello Docker World"

That is all .. Cheers :-)


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