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

1. 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)

1. Create the secret to store the database's password kubectl create -f spring-boot-app-secret.yaml

2. Deploy the application: kubectl create -f spring-boot-app.yaml

3. Create a load balancer to access your microservice externally: kubectl create -f spring-boot-load-balancer.yaml

4. 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:

1. 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

2. Now replace the configuration kubectl replace -f spring-boot-app.yaml

Scaling the database:

1. To scale Up/Down Couchbase, just change the number of servers inside the couchbase-cluster.yaml:

    ...
    servers:
        - size: 6 #It was 3 before
   

2. Now replace the configuration kubectl replace -f 6-couchbase-cluster.yaml