GitOps-Based Kubernetes Deployment with ArgoCD

This project demonstrates a complete GitOps workflow for deploying microservices to an EKS cluster using ArgoCD, Terraform, Helm, Docker, and GitLab CI/CD. It follows a multi-environment setup (dev, staging, prod) to ensure production-grade delivery pipelines and infrastructure management.

Get the detailed write-up here: https://medium.com/@cloudwithharshal/gitops-based-kubernetes-deployment-using-argocd-on-aws-eks-d38ab0e07dfe

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Project Structure

project/
├── app/                         # Dockerized microservices
│   ├── frontend/                # Nginx static app
│   └── backend/                 # Flask API service
├── terraform/                   # EKS + IAM + VPC via Terraform
├── helm-charts/                # Helm charts for frontend and backend
├── environments/               # Env-specific values for dev/staging/prod
├── argocd/                      # ArgoCD Application manifests
├── scripts/                     # ArgoCD install scripts
├── .gitlab-ci.yml               # GitLab CI pipeline
└── README.md                    # This file

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Features

• Provision EKS cluster using modular Terraform
• Dockerized Flask backend and Nginx frontend
• Deploy apps using Helm charts
• Support for dev, staging, prod environments
• GitOps automation with ArgoCD sync and drift detection
• CI/CD pipeline to build and push Docker images to AWS ECR

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Infrastructure Provisioning

Terraform modules create the following:

• VPC with public and private subnets
• EKS Cluster + Node Group
• IAM roles for EKS + nodes

Run:

cd terraform
terraform init
terraform apply

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Microservices

• Frontend: Static Nginx HTML site
• Backend: Flask API returning JSON message

Both services are Dockerized and built through GitLab CI/CD.

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Helm Chart Deployment

Each service has its own Helm chart under helm-charts/. Environment-specific values reside in:

environments/
├── dev/
├── staging/
└── prod/

Example (dev - frontend):

replicaCount: 1
image:
  repository: <ecr-url>/frontend
  tag: dev
service:
  type: ClusterIP
  port: 80

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GitOps with ArgoCD

ArgoCD is used to sync Helm-based services from Git directly to EKS.

Steps:

bash scripts/install-argocd.sh
kubectl apply -f argocd/frontend-app.yaml
kubectl apply -f argocd/backend-app.yaml

Includes automated sync and self-healing:

syncPolicy:
  automated:
    prune: true
    selfHeal: true

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GitLab CI/CD

.gitlab-ci.yml pipeline stages:

• build_backend
• build_frontend
• push_backend
• push_frontend

Each stage builds Docker images and pushes to AWS ECR using your AWS credentials.

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Environments Explained

Environment	ReplicaCount	ServiceType	Image Tag
Dev	1	ClusterIP	dev
Staging	2	ClusterIP	staging
Production	3	LoadBalancer	prod

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Author

Harshal Thakur
Cloud | DevOps | GitOps | Terraform | Kubernetes | ArgoCD | CI/CD

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Final Outcome

Deploy fully automated, environment-specific microservices to EKS with ArgoCD syncing everything straight from Git. Achieve fast rollouts, rollback support, and production-grade reliability.