GitOps CICD Demo

Using Kpack and Flux V2

The goal of this demo is to demonstrate how to implement CICD workflow with image update automation for a CRD (HelmRelease).

We will be using:

• Kpack – for continuous integration
• Flux V2 – for continuous delivery

What is Kpack?

Kpack a Kubernetes-native build service that builds container images on Kubernetes using Cloud Native Buildpacks. It takes source code repositories (like GitHub), builds the code into a container image, and uploads it to the container registry of your choice.

Kpack main benefits for this demo

• No Dockerfile - Kpack builds OCI-compliant containers directly from source code, eliminating the need for developers to build and maintain dockerfiles.
• Manage image build process – build and push to image repository.
• Manage image updates - detects changes to source code, dependency, or OS components and automatically updates containers.

What is Flux?

• Flux is a tool for keeping Kubernetes clusters in sync with sources of configuration (like Git repositories), and automating updates to configuration when there is new code to deploy.
• Flux is Based on a set of Kubernetes API extensions (CRDs) which control how git repositories and other sources of configuration (like helm repositories) are synced into the cluster.

Flux main benefits for this demo

• Just push to Git and Flux does the rest - enables continuous application deployment (CD) through automatic reconciliation.
• Provides GitOps for both apps and infrastructure - can also manage any Kubernetes resource.
• Automatic image update – Flux V2 can even push back to Git with automated container image updates, deploy those changes, and keep your deployments and CRDs up-to-date.

Prerequisites

What I used is in (parenthesis)

1. Running Kubernetes cluster (minikube version: v1.25.2)
2. Running Docker (Docker version 20.10.16)

Steps

1. Write simplistic Java code and push to git (Spring-Boot)
2. After the code is pushed to git, build the code to an image with Kpack and push it to an image repository (DockerHub)
3. Create a helm chart to deploy the application, and put in helm repository (ChartMuseum)
4. Configure Flux to update the helm repository and deploy the application automatically once there is a new image in the repository.

Step 1 - Write a Java app

I implemented a simple SpringBoot web app with a 'Hello World!' page, starting up on http://localhost:8080/

git clone https://github.com/GuyBalmas/example-app.git

delete the .git folder and push the repo to your GitHub

Step 2 - build the code to an image with Kpack

Follow the Kpack README.md at:

kpack-flux-demo/kpack/README.md

#or

https://github.com/GuyBalmas/kpack-flux-demo/blob/main/kpack/README.md

Step 3 - Create a helm chart and push to helm repository

I implemented a helm chart for the example-app SpringBoot web app, and it exists in its repo.

https://github.com/GuyBalmas/example-app/tree/main/chart

Follow the Install ChartMuseum section of the Kpack README.md:

kpack-flux-demo/kpack/README.md

#or

https://github.com/GuyBalmas/kpack-flux-demo/blob/main/kpack/README.md#install-chartmuseum

Step 4 - Configure Flux

Follow the Flux README.md at:

kpack-flux-demo/flux/README.md

#or

https://github.com/GuyBalmas/kpack-flux-demo/blob/main/flux/README.md