Microservices on Kubernetes

This is an example of how to run a microservices using Spring Boot and Couchbase on Kubernetes, the cool part of it is that you easily scale both your application and database.

Here I assume that you already have a real Kubernetes cluster up and running (I haven't tested on minikube yet)

All yaml files are inside the "kubernetes" folder

How to run this demo:

Deploying the database

Run the command:

kubectl create -f admission.yaml
kubectl create -f crd.yaml
kubectl create -f operator-role.yaml
kubectl create -f operator-service-account.yaml
kubectl create -f operator-role-binding.yaml
kubectl create -f operator-deployment.yaml
kubectl create -f secret.yaml
kubectl create -f couchbase-cluster.yaml

Deploying the Application

The docker image is public, so you don't need to touch the application (unless you would like to change something)

Create the secret to store the database's password kubectl create -f spring-boot-app-secret.yaml
Deploy the application: kubectl create -f spring-boot-app.yaml
Create a load balancer to access your microservice externally: kubectl create -f spring-boot-load-balancer.yaml

The load-balancer might take a while to be available (at least 5 minutes during my tests). Once it is up, get the External IP by running the following command: kubectl describe service spring-boot-load-balancer

It will return something like:

 Name:                     spring-boot-load-balancer
 Namespace:                default
 Labels:                   <none>
 Annotations:              <none>
 Selector:                 app=spring-boot-app
 Type:                     LoadBalancer
 IP:                       10.3.0.57
 LoadBalancer Ingress:   YOUR_EXTERNAL_IP_HERE
 Port:                     http  8080/TCP
 TargetPort:               8080/TCP
 NodePort:                 http  32340/TCP
 Endpoints:                10.2.2.7:8080
 Port:                     management  8081/TCP
 TargetPort:               8081/TCP
 NodePort:                 management  31415/TCP
 Endpoints:                10.2.2.7:8081
 Session Affinity:         None
 External Traffic Policy:  Cluster
 Events:                   <none>

Then, go to http://YOUR_EXTERNAL_IP_HERE:8080/ using your browser and congratulations! your Microservice is up and running.

You can call all the Restful endpoints from this app and Scale up and Down your Database and Application

Scaling Up and Down

Scaling the application:

To scale Up/Down you application, all you need to do is to change the number of replicas in the spring-boot-app.yaml file: ... spec: selector: matchLabels: app: spring-boot-app replicas: 3 #It was 1 before
Now replace the configuration kubectl replace -f spring-boot-app.yaml

Scaling the database:

To scale Up/Down Couchbase, just change the number of servers inside the couchbase-cluster.yaml:
```
 ...
 servers:
     - size: 6 #It was 3 before
```
Now replace the configuration kubectl replace -f 6-couchbase-cluster.yaml