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

1. Deploy postgres with a persistent volume claim

   kubectl create -f specs/postgres.yml
   

2. 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}")
   

3. Build the Spring Boot app

   ./mvnw -DskipTests package
   

4. 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
   

5. 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
   

6. Create an external load balancer for your app

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

7. 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

8. Scale your application

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

Updating your application

1. 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

1. Delete the Spring Boot app deployment

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

2. Delete the service for the app

   kubectl delete svc spring-boot-postgres-sample
   

3. Delete the hostname config map

   kubectl delete cm hostname-config
   

4. Delete Postgres

   kubectl delete -f specs/postgres.yml