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--- a/DEPLOY.md
+++ b/DEPLOY.md
@@ -14,6 +14,8 @@
 6. [Troubleshooting Guide](#6-troubleshooting-guide)
 7. [Updating the Application](#7-updating-the-application)
 8. [Teardown](#8-teardown)
+9. [CI/CD — Jenkins Multibranch Pipeline](#9-cicd--jenkins-multibranch-pipeline)
+10. [GitOps — ArgoCD (Reference)](#10-gitops--argocd-reference)

 ---

@@ -797,6 +799,275 @@ kubectl delete -f https://raw.githubusercontent.com/rancher/local-path-provision

 ---

+---
+
+## 9. CI/CD — Jenkins Multibranch Pipeline
+
+This project ships with a `Jenkinsfile` at the repo root that automates the full
+build → test → push → deploy lifecycle.
+
+### 9.1 Prerequisites on the Jenkins Server
+
+| Tool | Purpose | Install |
+|------|---------|---------|
+| Docker | Build & push images | `apt install docker.io` + add `jenkins` user to `docker` group |
+| kubectl | Apply k8s manifests | [Official install guide](https://kubernetes.io/docs/tasks/tools/) |
+| kustomize | Render overlays | `curl -s "https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/hack/install_kustomize.sh" | bash` |
+| NodeJS (v18+) | `npm ci` / `npm test` | Jenkins NodeJS plugin or system package |
+
+```bash
+# Add jenkins user to docker group (run on Jenkins host, then restart Jenkins)
+sudo usermod -aG docker jenkins
+sudo systemctl restart jenkins
+```
+
+### 9.2 Jenkins Plugins Required
+
+Install via **Manage Jenkins → Plugins**:
+
+| Plugin | Purpose |
+|--------|---------|
+| **Multibranch Pipeline** | Detects branches + PRs automatically |
+| **Docker Pipeline** | Docker credential binding |
+| **Credentials Binding** | Injects secrets into pipeline steps |
+| **NodeJS** | Managed Node.js installations |
+| **Git** | SCM checkout |
+
+### 9.3 Configure Jenkins Credentials
+
+Go to **Manage Jenkins → Credentials → System → Global credentials → Add**:
+
+| Credential ID | Kind | Fields | Used for |
+|---------------|------|--------|---------|
+| `dockerhub-credentials` | Username with password | Username: `subkamble` / Password: Docker Hub PAT | `docker push` |
+| `kubeconfig-secret` | Secret file | Upload your `~/.kube/config` | `kubectl` cluster access |
+
+> **Docker Hub PAT:** Generate at hub.docker.com → Account Settings → Security → New Access Token (Read/Write scope).
+
+> **kubeconfig tip:** If Jenkins runs inside the same cluster, use a ServiceAccount + RBAC instead of a kubeconfig file.
+
+### 9.4 Create the Multibranch Pipeline Job
+
+1. **Jenkins Dashboard → New Item**
+2. Name: `react-mysql` → select **Multibranch Pipeline** → OK
+3. Under **Branch Sources** → Add source → **Git**
+   - Repository URL: your repo URL
+   - Credentials: add repo access if private
+4. Under **Build Configuration** → Mode: **by Jenkinsfile** → Script Path: `Jenkinsfile`
+5. Under **Scan Multibranch Pipeline Triggers** → enable **Periodically if not otherwise run** (e.g. every 5 min), or configure a webhook (preferred)
+6. Save → **Scan Multibranch Pipeline Now**
+
+Jenkins will discover all branches and create sub-jobs automatically.
+
+### 9.5 Webhook Setup (recommended — avoids polling)
+
+**GitHub:**
+1. Repo → Settings → Webhooks → Add webhook
+2. Payload URL: `http://<JENKINS_URL>/multibranch-webhook-trigger/invoke?token=react-mysql`
+3. Content type: `application/json`
+4. Events: **Push** + **Pull requests**
+
+Install the **Multibranch Scan Webhook Trigger** plugin on Jenkins to handle the token.
+
+### 9.6 Branch Behavior Summary
+
+| Branch | Build | Test | Push Image | Deploy |
+|--------|-------|------|-----------|--------|
+| `main` | Yes | Yes | Yes (`latest` + SHA tag) | `k8s/overlays/onpremise` (production) |
+| `staging` | Yes | Yes | Yes (branch-SHA tag) | `k8s/overlays/minikube` (staging) |
+| `develop` | Yes | Yes | No | No |
+| `feature/**` | Yes | Yes | No | No |
+| PR branches | Yes | Yes | No | No |
+
+### 9.7 Image Tagging Convention
+
+| Branch | Tag format | Example |
+|--------|-----------|---------|
+| `main` | `latest` + `<sha8>` | `latest`, `a1b2c3d4` |
+| `staging` | `staging-<sha8>` | `staging-a1b2c3d4` |
+| `feature/login` | `feature-login-<sha8>` | `feature-login-a1b2c3d4` |
+
+### 9.8 First-Run Checklist
+
+```bash
+# Verify Jenkins can reach Docker Hub
+docker login -u subkamble
+
+# Verify Jenkins can reach the cluster
+kubectl get nodes
+
+# Verify kustomize is on PATH
+kustomize version
+
+# Trigger a manual build for main branch from Jenkins UI
+# then watch the Console Output for each stage
+```
+
+### 9.9 Rollback
+
+```bash
+# List available image tags (via Docker Hub API or local docker images)
+docker images subkamble/react-mysql-backend
+
+# Pin a specific tag manually and re-deploy
+cd k8s/base
+kustomize edit set image \
+    subkamble/react-mysql-backend=subkamble/react-mysql-backend:<previous-sha> \
+    subkamble/react-mysql-frontend=subkamble/react-mysql-frontend:<previous-sha>
+cd -
+kubectl apply -k k8s/overlays/onpremise
+kubectl rollout status deployment/backend  -n react-mysql
+kubectl rollout status deployment/frontend -n react-mysql
+```
+
+---
+
+## 10. GitOps — ArgoCD (Reference)
+
+> The Jenkinsfile contains fully commented-out ArgoCD pipeline stages.
+> Follow this section to activate GitOps mode.
+
+### 10.1 Install ArgoCD
+
+```bash
+kubectl create namespace argocd
+kubectl apply -n argocd \
+  -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
+
+# Wait for all ArgoCD pods to be ready
+kubectl wait --for=condition=Ready pods --all -n argocd --timeout=180s
+
+# Expose the ArgoCD API server (choose one):
+
+# Option A — Port-forward (local access only)
+kubectl port-forward svc/argocd-server -n argocd 8080:443
+
+# Option B — LoadBalancer (on-prem with MetalLB or cloud)
+kubectl patch svc argocd-server -n argocd \
+  -p '{"spec":{"type":"LoadBalancer"}}'
+
+# Option C — Ingress (add argocd.myapp.local to your Ingress controller)
+```
+
+### 10.2 Get Initial Admin Password
+
+```bash
+kubectl get secret argocd-initial-admin-secret \
+  -n argocd \
+  -o jsonpath="{.data.password}" | base64 -d && echo
+
+# Login
+argocd login localhost:8080 --username admin --password <above-password> --insecure
+
+# Change password immediately
+argocd account update-password
+```
+
+### 10.3 Apply ArgoCD Application Manifests
+
+Create the two Application objects (one per environment).
+These are documented in full inside the `Jenkinsfile` comments.
+Here is the summary of what they do:
+
+| Application | Watches branch | Overlay | Sync policy |
+|-------------|---------------|---------|------------|
+| `react-mysql-production` | `main` | `k8s/overlays/onpremise` | Automated (prune + selfHeal) |
+| `react-mysql-staging` | `staging` | `k8s/overlays/minikube` | Automated (prune + selfHeal) |
+
+```bash
+# Copy the YAML blocks from the Jenkinsfile comments into files, then:
+kubectl apply -f argocd/application-production.yaml
+kubectl apply -f argocd/application-staging.yaml
+
+# Verify apps are registered
+argocd app list
+```
+
+### 10.4 Jenkins Credentials for GitOps Mode
+
+Add these alongside the existing credentials:
+
+| Credential ID | Kind | Purpose |
+|---------------|------|---------|
+| `argocd-auth-token` | Secret text | ArgoCD API token for `argocd app sync` |
+| `gitops-ssh-key` | SSH username with private key | Push image tag updates back to Git |
+
+**Generate an ArgoCD API token:**
+```bash
+argocd account generate-token --account admin
+# Copy the output → paste as the 'argocd-auth-token' secret text
+```
+
+### 10.5 Activate GitOps in the Jenkinsfile
+
+1. Open `Jenkinsfile`
+2. Remove the active **Deploy** and **Smoke Test** stages (or leave them as fallback)
+3. Uncomment the `Update GitOps Manifest` and `ArgoCD Sync` stage blocks in the GitOps section at the bottom
+4. Replace `YOUR_ARGOCD_SERVER` with your ArgoCD server hostname/IP
+5. Replace `YOUR_ORG` in the git clone URL with your GitHub org/username
+6. Commit and push — Jenkins picks up the change automatically
+
+### 10.6 GitOps Flow Diagram
+
+```
+Developer pushes code
+        │
+        ▼
+   Jenkins CI
+   ┌─────────────────────────────────────┐
+   │ 1. npm ci → test                    │
+   │ 2. docker build + push :<sha-tag>   │
+   │ 3. kustomize edit set image         │
+   │ 4. git commit + push [skip ci]      │
+   └─────────────────┬───────────────────┘
+                     │ Git push (image tag bump)
+                     ▼
+             Git Repository
+             (k8s/base/kustomization.yaml updated)
+                     │
+                     │ ArgoCD polls every 3 min
+                     │ (or Jenkins triggers sync via argocd CLI)
+                     ▼
+              ArgoCD detects drift
+              ┌────────────────────────────┐
+              │ kubectl apply -k overlay/  │
+              │ prune removed resources    │
+              │ self-heal manual changes   │
+              └────────────┬───────────────┘
+                           │
+                           ▼
+                    Kubernetes Cluster
+                    (react-mysql namespace updated)
+```
+
+### 10.7 ArgoCD Quick Reference
+
+```bash
+# View app status
+argocd app get react-mysql-production
+
+# Force immediate sync (skip waiting for poll interval)
+argocd app sync react-mysql-production
+
+# Rollback to previous revision
+argocd app history react-mysql-production
+argocd app rollback react-mysql-production <revision-id>
+
+# Pause auto-sync (for maintenance)
+argocd app set react-mysql-production --sync-policy none
+
+# Resume auto-sync
+argocd app set react-mysql-production --sync-policy automated
+
+# Delete app (does NOT delete k8s resources by default)
+argocd app delete react-mysql-production
+
+# Delete app AND k8s resources
+argocd app delete react-mysql-production --cascade
+```
+
+---
+
 ## Quick Reference Card

 ```bash