Local Kubernetes Development with Java/Spring Boot application (Workshop)

This repository contains sample Spring Boot application, k8s definitions and scaffold setup.

What You will learn

• How to set up Readiness and liveness probes.
• How to wait for container lifecycle processes to finish.
• How to enable graceful shutdown.
• How to expose metrics.
• How to configure logstash-logback-encoder.
• How to debug application running inside k8s.
• How to use live-reload feature for faster development.
• How to use common kubectl commands and generate k8s definitions.
• How to use Skaffold for local Kubernetes development.
• How to use Cloud Code plugin in IntelliJ.

Getting Started

Prerequisites

• Java 11
• Docker
• Kubernetes

Installation

Build docker image.

./gradlew bootBuildImage

Usage

Kubectl

• Apply k8s configurations files from a directory.

  kubectl create -f k8s/namespace.yml
  kubectl apply -f k8s/

• Port forward spring-k8s-workshop service.

  kubectl port-forward svc/spring-k8s-workshop 8080:8080

• Visit http://localhost:8080/hello resource.

• Play with kubectl api, see section 'Additional Useful Commands'.

• [Optionally] Install and play with k9s tool (https://github.com/derailed/k9s).

• Destroy all spring-k8s-workshop components.

  kubectl delete all --all -n spring-k8s-workshop
  kubectl delete ns spring-k8s-workshop

Skaffold

• Run a pipeline in development mode.

  skaffold dev --port-forward

  *** --port-froward - expose ports.

  *** --trigger=manual - disable auto-build (triggered after file change). Allowed values polling, notify, manual.

• Visit http://localhost:8080/hello resource.

• Make some changes inside HelloController class to see live reload feature.

• Stop skaffold dev (CTRL + C).

• Run skaffold in debug mode.

  # Similar to `dev`, but configures the pipeline for debugging. Auto-build and sync is disabled by default to prevent
  # accidentally tearing down debug sessions.
  skaffold debug --port-forward

• Configure remote debugging in Intellij Idea.

• Start Debug session in Intellij Idea and create breakpoint inside HelloController.class

Cloud Code

• Watch this amazing Google Cloud Tech introduction how to use plugin - Cloud-native development in the IDE with Cloud Code.

• Install Cloud Code plugin from https://plugins.jetbrains.com/plugin/8079-cloud-code.

• Play again with sample application this time using Cloud Code plugin;)

Additional Useful Commands

Create k8s definitions using --dry-run.

# Create secret definition
kubectl create secret generic spring-k8s-workshop-secret --dry-run=client -o=yaml > secret.yaml

# Creating deployment definition
kubectl create deployment deployment_name --image=spring-k8s-workshop:0.0.1-SNAPSHOT --dry-run=client -o=yaml > deployment.yaml

# Create Service definition
kubectl create service clusterip spring-k8s-workshop --tcp=8080:8080 --dry-run=client  -o=yaml >> service.yaml

# Create config map from yml file
kubectl create configmap --dry-run somename --from-file=./src/main/resources/application-dev.yml -o=yaml

Create Secret.

# Create secret and base64 encode it
echo -n "Secret from k8s" | base64

# Create secret, base64 encode it and add it to your clipboard
echo -n "Secret from k8s" | base64 | pbcopy

References

• Spring on Kubernetes
• Spring configtree
• Skaffold - Local Kubernetes Development Made Easy
• Skaffold - Github releases
• Google Cloud - Cloud Code
• Cloud-native development in the IDE with Cloud Code
• Best Practices to Spring to Kubernetes Easier and Faster by Ray Tsang
• k9s

License

Distributed under the MIT License. See LICENSE for more information.