Blue-Green Deployment to Kubernetes Demo

This repository serves as a demonstration of implementing blue-green deployment to Kubernetes using continuous integration and continuous deployment (CI/CD) pipelines. The goal is to showcase a workflow that automates the deployment process, including building the application, pushing the image to Google Artifact Registry, and deploying the application to a Google Kubernetes Engine (GKE) cluster.

Image Credits: https://www.ianlewis.org/

What is Blue-Green Deployment

A blue-green deployment is a software release strategy and deployment methodology used in the world of DevOps and continuous delivery to minimize downtime and reduce the risk associated with deploying new versions of an application.

Requirements

Before you get started, ensure you have the following prerequisites:

• Google Cloud Platform (GCP) Account and Project: You'll need a GCP account and a project to host your GKE cluster.

• GKE Cluster, Artifact Registry Repository, and Service Account: You should have a GKE cluster set up, an Artifact Registry repository configured, and a Service Account with appropriate permissions. You can use the Terraform provisioning repository to provision these requirements automatically.

How It Works

This repository automates the blue-green deployment process using GitHub Actions. Here's how it works:

1. Push to the main Branch: When you push changes to the main branch, a GitHub Actions workflow is triggered.

2. Build the Application: The workflow builds the application and prepares it for deployment.

3. Push to Artifact Registry: The application image is pushed to Google Artifact Registry, making it accessible for deployment.

4. Deploy to GKE: The ./scripts/deploy.sh script is executed with four parameters:

   • APP_NAME: The name of your application.
   • VERSION: The version/tag of the application image.
   • IMAGE: The location of the application image in Artifact Registry.
   • DEPLOYMENTFILE: The path to the Kubernetes deployment manifest template (./k8s/deploy.tmpl).

5. Blue-Green Deployment on GKE: The script uses the Kubernetes deployment manifest template to create a green deployment on the GKE cluster. It waits until the deployment is successful and all pods are ready.

6. Service Switch: If a service exists, the script patches it to switch to the new (green) version of the app. If not, it creates the service.

7. Cleanup: Finally, the script deletes old (blue) deployments to ensure a clean environment.

Deployment Steps

To deploy your application using this repository, follow these steps:

1. Clone or Fork the Repository: Clone or fork this repository to your GitHub account or your local machine.

2. Provide Environment Secrets: Configure the necessary environment secrets for the GitHub Actions workflow. These secrets typically include credentials and configuration for GCP, GKE, and Artifact Registry.

3. Make Changes and Push: Customize the application as needed and commit your changes to the main branch. Pushing your changes will trigger the GitHub Actions workflow, and you should see your application deployed with blue-green deployment on your GKE cluster.

Feel free to explore and modify this repository to suit your specific requirements. Happy deploying! 🚀