Deploying a Spring Boot application in Kubernetes, on AWS

This tutorial covers deploying a sample application in Kubernetes, on AWS.

The application is simple, but have some different parts:

• A Spring Boot application exposing a REST API, to scale on multiple nodes. The application comes from an old post of mine Implementing HAL hypermedia REST API using Spring HATEOAS.
• A data store, a standalone H2 server.
• Application's environment-specific configuration and secrets injected using a K8s Secret
• Persistent data stored on a separate EBS volume, so no data loss when the Pod restart.

Requirements

For running this tutorial you need:

• An AWS account (although most of the infrastructure might be included in the free-tier, some component will not, and running the cluster will cost a few bucks).
• A DockerHub account (this is free)

You also need the following software on your machine:

• Docker (tested with v1.9.1)
• Kubernetes (tested with v1.3.5)
• AWS CLI (also requires Python)
• Maven (to compile the sample Spring Boot application)

Labs

All steps are entirely manual. Some Kubernetes specs files must be manually modified before using them.

• Build application and Docker images and publish them to public DocherHub repositories.
• (optional) Run containers locally, in Docker
• Create Kubernetes cluster on AWS
• Lauch application components in Kubernetes
• Experiment: No data is lost when db Pod restart
• Experiment: Update application image
• Experiment: Scale up Nodes (Minions)

Please, also read some note about security.

Cleanup

To shut down the Kubernetes cluster, we use the provided script:

$ kube-down.sh

Alternatively, you may keep the cluster running but remove all the component we created:

$ kubectl delete deployment frontend h2server
deployment "frontend" deleted
deployment "h2server" deleted

$ kubectl delete svc frontend h2server h2server-ui
service "frontend" deleted
service "h2server" deleted
service "h2server-ui" deleted

$ kubectl delete secret sample-app-cfg
secret "sample-app-cfg" deleted

Also, don't forget to remove the EBS Volume we created for H2 data:

$ aws ec2 delete-volume --volume-id <volume-id>