Minikube – Rapid Dev & Testing for Kubernetes

One of the attendees from Kubernetes for Java Developers training suggested to try minikube for simplified Kubernetes dev and testing. This blog will show how to get started with minikube using a simple Java application.

minikube-logo

Minikube starts a single node Kubernetes cluster on your local machine for rapid development and testing. Requirements lists the exact set of requirements for different operating systems.

This blog will show:

  • Start one node Kubernetes cluster
  • Run Couchbase service
  • Run Java application
  • View Kubernetes Dashboard

All Kubernetes resource description files used in this blog are at github.com/arun-gupta/kubernetes-java-sample/tree/master/maven.

Start Kubernetes Cluster using Minikube

Create a new directory with the name minikube.

In that directory, download kubectl CLI:

Download minikube CLI:

Start the cluster:

The list of nodes can be seen:

More details about the cluster can be obtained using the kubectl cluster-info command:

Behind the scenes, a Virtual Box VM is started.

Complete set of commands supported can be seen by using --help:

Run Couchbase Service

Create a Couchbase service:

This will start a Couchbase service. The service is using the pods created by the replication controller. The replication controller creates a single node Couchbase server.

The configuration file is at github.com/arun-gupta/kubernetes-java-sample/blob/master/maven/couchbase-service.yml and looks like:

Run Java Application

Run the application:

The configuration file is at github.com/arun-gupta/kubernetes-java-sample/blob/master/maven/bootiful-couchbase.yml and looks like:

This is run-once job which runs a Java (Spring Boot) application and upserts (insert or update) a JSON document in Couchbase.

In this job, COUCHBASE_URI environment variable value is set to couchbase-service. This is the service name created earlier. Docker image used for this service is arungupta/bootiful-couchbase and is created using fabric8-maven-plugin as shown at github.com/arun-gupta/kubernetes-java-sample/blob/master/maven/webapp/pom.xml#L57-L68. Specifically, the command for the Docker image is:

This ensures that COUCHBASE_URI environment variable is overriding spring.couchbase.bootstrap-hosts property as defined in application.properties of the Spring Boot application.

Kubernetes Dashboard

Kubernetes 1.4 included an updated dashboard. For minikube, this can be opened using the following command:

 

The default view is shown below:
minikube-dashboard-1-4

But in our case, a few resources have already been created and so this will look like as shown:

minikube-dashboard-couchbase

Notice, our Jobs, Replication Controllers and Pods are shown here.

Shutdown Kubernetes Cluster

The cluster can be easily shutdown:

couchbase.com/containers provide more details about running Couchbase using different orchestration frameworks. Further references:

Source: blog.couchbase.com/2016/september/minikube-rapid-dev–testing-kubernetes

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