Three-Tier MERN App: DevSecOps on AWS EKS

A complete end-to-end pipeline to build, scan, and deploy a production-ready MERN (MongoDB, Express, React, Node.js) application on AWS EKS using Jenkins, ArgoCD, and Kubernetes with integrated security and monitoring.

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🏗️ Project Overview

• Infrastructure: EKS-Terraform-setup for cluster, VPC, and networking (step 1/2).
• Application: MERN (React frontend, Node/Express backend, MongoDB database), with Dockerfiles for each.
• Kubernetes Deployments: YAML manifest files for all app tiers, including persistent storage and secure secrets.
• Ingress: AWS Application Load Balancer (ALB) via AWS Load Balancer Controller.
• Deployment Method: Automated via ArgoCD GitOps after CI image tagging.
• Monitoring: Prometheus and Grafana.
• Security: Integrated with SonarQube, OWASP Dependency Check, Trivy.

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🗂️ Repository Structure

├── Application-Code/
│ ├── frontend/ # React code + Dockerfile
│ └── backend/ # Node/Express code + Dockerfile
├── Kubernetes-Manifests-file/
│ ├── Frontend/
│ │ ├── deployment.yaml
│ │ └── service.yaml
│ ├── Backend/
│ │ ├── deployment.yaml
│ │ └── service.yaml
│ ├── Database/
│ │ ├── deployment.yaml
│ │ ├── service.yaml
│ │ ├── pv.yaml
│ │ ├── pvc.yaml
│ │ └── secrets.yaml
│ └── Ingress/
│ └── ingress.yaml
├── Jenkins-Pipeline-Code/
│ ├── Jenkinsfile-Frontend
│ └── Jenkinsfile-Backend

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🚦 End-to-End Flow

1️⃣ Infrastructure Provisioning

Provision your EKS cluster and networking in AWS using EKS-Terraform-setup with Jenkins automation.

2️⃣ Build & Secure with Jenkins

For both frontend and backend:

• Clean workspace, checkout code.
• SonarQube: Static code analysis.
• OWASP Dependency Check: Scan for library vulnerabilities.
• Trivy: Scan files/directories for vulnerabilities.
• Build Docker image for app.
• Push image to AWS ECR.
• Trivy (Image Scan): Scan built image.
• Update app deployment manifest with new image tag and push to GitHub.

3️⃣ GitOps Delivery through ArgoCD

• ArgoCD watches repository for manifest changes.
• Automatically deploys updated backend, frontend, and DB on EKS cluster.
• Ingress resource provisions public ALB via AWS Load Balancer Controller.

4️⃣ Robust, Real-Time Monitoring

• Prometheus: Metrics scraping/collection.
• Grafana: Visualization dashboards linked to your EKS and workloads.

5️⃣ Secure Database

• MongoDB runs as a managed Kubernetes Deployment with PersistentVolumeClaim.
• Secrets stored in K8s secret objects.

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📝 Key Kubernetes Manifests

• Ingress: ingress.yaml defines ALB rules/routes /api → backend, / → frontend, health/ready probes.
• Frontend/Backend/DB Deployments: Each with dedicated Docker image, ECR registry, rolling updates, and health checks.
• Secrets & Volumes: Secure, persistent DB storage and access credentials via Kubernetes secrets.

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🔍 Monitoring & Security Tools

• SonarQube: Quality gate for every PR/build.
• OWASP Dependency-Check: Finds vulnerable packages.
• Trivy: Scans files and containers for vulnerabilities.
• Prometheus: In-cluster monitoring.
• Grafana: Dashboards for real-time insights.

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📊 See The Pipeline In Action

Check my LinkedIn post for a full visual walkthrough, including Jenkins, ArgoCD, SonarQube, Prometheus, and Grafana in action:

• [👉 View LinkedIn Post (https://www.linkedin.com/posts/gauravpatil20_aws-eks-devsecops-activity-7363199518063972354-SLtu?utm_source=share&utm_medium=member_desktop&rcm=ACoAAEDC-98BDnksxUIcgMuM03zRe0M_L1Xka-Q)]

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💡 Quick Start

1. Provision EKS:
   See EKS-Terraform-setup to provision cluster and networking.

2. Connect Jenkins to AWS & GitHub:
   Ensure all needed credentials are set up (see environment blocks in Jenkinsfile).

3. Create ECR repos:
   Make sure AWS ECR repos for frontend and backend exist.

4. Setup SonarQube, Prometheus, and Grafana:
   Deploy them to EKS as per scripts/guides.

5. Create ArgoCD apps:
   To sync Kubernetes manifest folders for frontend, backend, database, and ingress.

6. Run Jenkins Pipelines:
   Pipelines build, scan, push images, and update manifests, triggering ArgoCD auto-deployment.

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🙏 Acknowledgements & Credits

• Architecture diagram and methodology by AmanPathak-DevOps
• Special thanks to iam-veeramalla and Aman for their amazing explanations and guidance throughout the project development.

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