Preview Environments Example

This repository demonstrates how to set up preview environments for your applications on a local Kubernetes cluster using Minikube, ArgoCD, GitHub Actions, and Helm.

Project Overview

The project consists of a simple FastAPI application, a Dockerfile to containerize it, a Helm chart to deploy it, and the necessary CI/CD and GitOps configurations to automate the creation of preview environments.

How it Works

Push to a branch: A developer pushes code to a branch in the GitHub repository.
CI Pipeline: A GitHub Actions workflow is triggered, which builds a Docker image and pushes it to GitHub Container Registry (GHCR). The image is tagged with the commit SHA.
Update Helm Values: The workflow then updates the values.yaml file in the helm directory with the new image tag and commits the change to the repository.
Pull Request: The developer creates a pull request and adds the preview label.
ArgoCD ApplicationSet: An ArgoCD ApplicationSet is configured to watch for pull requests with the preview label. When it detects a new pull request, it automatically creates a new application in ArgoCD.
Preview Environment: The ArgoCD application deploys the application to a new namespace in the Kubernetes cluster using the Helm chart from the pull request branch. The ingress is configured to be accessible at pr-<branch-name>.<your-domain>.

Local Setup with Minikube

This section provides a step-by-step guide to setting up the preview environments on a local Minikube cluster.

Prerequisites

1. Start Minikube

Start a new Minikube cluster:

minikube start

2. Enable Ingress

Enable the ingress controller addon:

minikube addons enable ingress

3. Install ArgoCD

Install ArgoCD using the official Helm chart:

helm repo add argo https://argoproj.github.io/argo-helm
helm repo update
helm install argocd argo/argo-cd --namespace argocd --create-namespace

4. Get Minikube IP

Get the IP address of your Minikube cluster:

minikube ip

5. Update ApplicationSet

Update the appset/appset.yml file with the Minikube IP address. Replace 192-168-67-2 in the ingress.host value with the IP address from the previous step.

For example, if your Minikube IP is 192.168.49.2, the ingress.host should be:

value: pr-{{branch}}.192-168-49-2.nip.io

6. Apply the ApplicationSet

Apply the ApplicationSet to your cluster:

kubectl apply -f appset/appset.yml -n argocd

Now, when you create a pull request with the preview label, ArgoCD will automatically create a preview environment for you.

A Note on `nip.io`

This project uses nip.io to provide a wildcard DNS for your local IP address. This allows you to access your preview environments using a domain name like pr-my-branch.192-168-1-1.nip.io, which resolves to 192.168.1.1. This service is free to use and does not require any registration.

CI/CD Pipeline

The CI/CD pipeline is defined in .github/workflows/build-and-deploy.yml. It consists of two jobs:

build-push: Builds the Docker image and pushes it to GHCR.
deployment-job: Updates the values.yaml file with the new image tag.