# Kubernetes Task Manager - Technical Documentation

## Project Purpose

This project demonstrates a production-like Kubernetes deployment featuring:
- Multi-container application
- Persistent storage
- Scalable frontend
- Proper resource management

## Deployment Components

### Core Objects

| Object Type       | Name                | Purpose                                                                 |
|-------------------|---------------------|------------------------------------------------------------------|
| `Namespace`       | `web-app`           | Isolates all application resources                                     |
| `Deployment`      | `web-app`           | Manages 2 replicas of frontend pods                                    |
| `StatefulSet`     | `mysql`             | Manages database pod with stable network identity

| `Service`         | `web-app-service`   | Exposes frontend on NodePort 30080                                     |
| `PersistentVolume`| `mysql-pv`          | Provides 5Gi storage for database                                      |

### Container Images

| Component | Image                       | Port | Notes                                  |
|-----------|-----------------------------|------|----------------------------------------|
| Frontend  | `k8s-task-manager-frontend` | 80   | Custom-built Nginx image               |
| Database  | `mysql:5.7`                 | 3306 | With preconfigured credentials         |
| Backend   | `k8s-task-manager-api`      | 8080 | Node.js/Express REST API               |

## Deployment Workflow

```mermaid
graph TD
    A[prepare-app.sh] --> B[Creates PV directories]
    B --> C[Builds frontend image]
    C --> D[start-app.sh]
    D --> E[Creates Namespace]
    E --> F[Deploys PV/PVC]
    F --> G[Deploys MySQL StatefulSet]
    G --> H[Deploys Frontend]
    H --> I[Creates Service]

# Key Configuration Details
## Resource Allocation

Frontend:

resources:
  requests:
    cpu: "100m"
    memory: "128Mi"
  limits:
    cpu: "250m"
    memory: "256Mi"


Database:

resources:
  requests:
    cpu: "500m"
    memory: "512Mi"
  limits:
    cpu: "1000m"
    memory: "1Gi"

Backend:

```yaml
resources:
  requests:
    cpu: "200m"
    memory: "256Mi"
  limits:
    cpu: "500m"
    memory: "512Mi"

Storage Configuration

# persistentvolume.yaml
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data/mysql"


# Operational Procedures
## Accessing the Application

Local Development:
minikube service web-app-service -n web-app

Production Access:
http://<node-ip>:30080

Monitoring Commands:
# Check pod status
kubectl get pods -n web-app -w

# View frontend logs
kubectl logs -n web_app deploy/web-app -f

# Verify database health
kubectl exec -n web-app mysql-0 -- mysql -uroot -ppassword -e "SHOW DATABASES;"

# Maintenance Tasks
Scaling Frontend:
kubectl scale -n web-app deployment/web-app --replicas=3

Database Backup:
kubectl exec -n web-app mysql-0 -- \
  mysqldump -u root -ppassword taskmanager > backup_$(date +%F).sql

# Security Notes
Database Credentials:

Default credentials are for demonstration only

In production, use:
envFrom:
- secretRef:
    name: mysql-credentials

Network Exposure:
Current: NodePort (30080)
Recommended: Ingress with TLS termination

# Troubleshooting Guide
Symptom	                        Diagnostic Steps        	        Resolution
Frontend not responding	kubectl get svc -n web-app	                Verify NodePort configuration
Database pod crash loops	kubectl describe pod mysql-0 -n web-app	Check storage permissions
High CPU usage	                kubectl top pods -n web-app      	Adjust resource limits

Cleanup Procedure
# Full uninstall
./stop-app.sh

# Optional: Remove persistent data
sudo rm -rf /mnt/data/mysql