mkjelland/spring-boot-postgres-on-k8s-sample

README

spring-boot-postgres-on-k8s

This demo deploys a simple Spring Boot web application that connects to Postgres onto a Kubernetes cluster.

You can watch this demo along with an introduction to Kubernetes concepts here.

Prerequisites

Kubernetes cluster with kubectl installed and configured to use your cluster
docker cli installed, you must be signed into your Docker Hub account

Deploy Spring Boot app and Postgres on Kubernetes

Deploy postgres with a persistent volume claim
```
kubectl create -f specs/postgres.yml
```

Create a config map with the hostname of Postgres

kubectl create configmap hostname-config --from-literal=postgres_host=$(kubectl get svc postgres -o jsonpath="{.spec.clusterIP}")

Build the Spring Boot app
```
./mvnw -DskipTests package
```

Build a Docker image and push the image to Docker Hub

docker build -t <your Docker Hub account>/spring-boot-postgres-on-k8s:v1 .
docker push <your Docker Hub account>/spring-boot-postgres-on-k8s:v1

Replace <your Docker Hub account> with your account name in specs/spring-boot-app.yml, then deploy the app
```
kubectl create -f specs/spring-boot-app.yml
```

Create an external load balancer for your app

kubectl expose deployment spring-boot-postgres-sample --type=LoadBalancer --port=8080

Get the External IP address of Service, then the app will be accessible at http://<External IP Address>:8080
```
kubectl get svc spring-boot-postgres-sample
```
Note: It may take a few minutes for the load balancer to be created

Scale your application

kubectl scale deployment spring-boot-postgres-sample --replicas=3

Updating your application

Update the image that the containers in your deployment are using

kubectl set image deployment/spring-boot-postgres-sample spring-boot-postgres-sample=<your Docker Hub account>/spring-boot-postgres-on-k8s:v2

Deleting the Resources

Delete the Spring Boot app deployment

kubectl delete -f specs/spring-boot-app.yml

Delete the service for the app

kubectl delete svc spring-boot-postgres-sample

Delete the hostname config map
```
kubectl delete cm hostname-config
```
Delete Postgres
```
kubectl delete -f specs/postgres.yml
```