k8s-debugger

The k8s debugger is a simple spring boot mvc application that contains a simple html page. This app is designated to be hosted on a kubernetes environment. It has only two features :

• A simple html home page
• Some rest api endpoints

For the html page. It's an index.html which exposes some data of the current container (on which the app is running) like :

• The Hostname
• The IP Address
• The Port on which the app is running
• If you have several containers, each one will have its own background color

The rest api endpoints are the actuator endpoints to check the health and the build info of the application. You can check them on :

• /actuator/health
• /actuator/liveness
• /actuator/readiness
• /actuator/info

Requirements

• JDK 20
• You IDE

Run

Local

You can run the app on your localhost as a simple spring boot application and check the home page from :

• http://localhost:8080/

Minikube

You can also run the app on your minikube environment using the yaml file under :

• deploy/k8s-debugger.yaml

Get the service external url :

minikube service k8s-debugger-service -n default --url

http://172.19.242.246:31003

and check then the url from your browser.

Build

If you check the sources, you'll find two important files for the build :

• build.sh
• .github/workflows/build-push-docker-image.yml

You can run the build.sh script which will ask you for the type of the build. If this is a test version, you can choose uat otherwise if this is a corporate version choose production.

The script will push the tag :

• uat : if you select the first option
• X.x.x : which is your corporate version if you select the second option

After pushing, the Build and Push Docker Image github action will be triggered. This workflow, will :

• Define the docker image tag : which is uat or X.X.X suffixed by the current date-time and the sha1 of the last commit.
• Package the project
• Build the docker image
• Push the docker image with the defined tag and a latest tag

The docker image will be hosted on the dockerhub account, but feel free to change that :

• https://hub.docker.com/r/mouhamedali/k8s-debugger

Release

We are using Helm charts to release our application. There is an action responsible for pushing charts which is called Push an Helm Release on GCR and you can find it in the actions list of the repo.

You can find the char here :

• https://github.com/mamdouni/k8s-debugger/pkgs/container/k8s-debugger

References

• https://mkyong.com/spring-boot/spring-boot-hello-world-example-thymeleaf/
• https://spring.io/guides/gs/testing-web/
• https://medium.com/@johnidouglasmarangon/accessing-docker-tag-as-an-environment-variable-inside-a-docker-container-project-6d944cab4ff7
• https://minikube.sigs.k8s.io/docs/handbook/accessing/
• https://github.com/docker/build-push-action#examples
• https://event-driven.io/en/how_to_buid_and_push_docker_image_with_github_actions/
• https://dev.to/jpoehnelt/environment-variables-in-github-docker-build-push-action-23pj
• https://helm.sh/docs/helm/helm_lint/
• https://helm.sh/docs/helm/helm_package/
• https://medium.com/google-cloud/ci-gitops-with-helm-github-actions-github-container-registry-and-config-sync-836913e74e79

Nigel Brown work

Inspired from the nginxhello repo :

• https://github.com/nbrownuk/gitops-nginxhello
• https://github.com/nbrownuk/gitops-app-nginxhello
• https://github.com/nbrownuk/gitops-config-nginxhello
• https://app.pluralsight.com/library/courses/gitops-kubernetes-flux-2-automate-deployments-using/table-of-contents