Flask Web + DB on Kubernetes

🧰 Project Overview

This project demonstrates how to:
• Containerize a simple Flask web app and a mock database API
• Deploy both services using Kubernetes
• Use inter-service communication inside the cluster
• Access the frontend via browser and retrieve data from the backend

📦** Project Structure**

🔧 Prerequisites
• Docker
• Minikube
• kubectl
• A basic understanding of Python and terminal commands

*Step 1: Create the Flask Apps
Web/app.py (file)
*

📄 db/app.py

🐳 Step 2: Dockerize the Apps

📄 web/Dockerfile

📄 db/Dockerfile

📄 requirements.txt (for both)

🧪 Step 3: Build Docker Images in Minikube

RUN:

minikube start
eval $(minikube docker-env)

Then build:
docker build -t flask-web ./web
docker build -t flask-db ./db
**
🧾 Step 4: Create Kubernetes Deployment & Service Files
**
📄 db-deployment.yaml

📄 web-deployment.yaml

🚀 Step 5: Deploy to Kubernetes

kubectl apply -f db-deployment.yaml
kubectl apply -f web-deployment.yaml

Check the status:

kubectl get pods
kubectl get services

🌐 Step 6: Access the Web App

minikube service web-service --url

*I went on to improve the project by adding monitoring and logging *

✅ Monitoring using Prometheus + Grafana
✅ Logging using Loki + Grafana

*Goal *

Prometheus - Collect metrics (CPU, memory, HTTP request)
Grafana - Visualize metrics and logs
Loki - Collect and search logs

🧱 Prerequisites

Make sure you have:
• Minikube
• kubectl
• Your web and db services already deployed
• Optional: Helm (we’ll use it for easier installation)

*Part 1: Monitoring with Prometheus + Grafana *

✅ Step 1: Enable Helm in Minikube (optional but recommended)
**
minikube addons enable helm-tiller
**
✅ Step 2: Add Helm Repos

helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo add grafana https://grafana.github.io/helm-charts
helm repo update

✅ Step 3: Install Prometheus

helm install prometheus prometheus-community/prometheus

This installs:
• Prometheus server
• Node exporter
• Alertmanager

Check it: kubectl get pods
**
✅ Step 4: Install Grafana**

helm install grafana grafana/grafana \
--set adminPassword='admin' \
--set service.type=NodePort

Find the Grafana service:

minikube service grafana --url

Log in with:
• User: admin
• Password: admin

✅ Step 5: Add Prometheus as Data Source in Grafana

1. Open Grafana (from minikube service grafana)
2. Go to Settings > Data Sources
3. Click Add Data Source
4. Choose Prometheus
5. URL: http://prometheus-server
6. Click Save & Test Now you’re ready to build dashboards! ** ✅ Step 6: Add Metrics to Your Flask Apps (Optional but recommended) ** Add prometheus_flask_exporter to both web/requirements.txt and db/requirements.txt:

Flask
requests
prometheus_flask_exporter

Update both app.py files:

from prometheus_flask_exporter import PrometheusMetrics

metrics = PrometheusMetrics(app)

Rebuild and redeploy the images:

eval $(minikube docker-env)
docker build -t flask-web ./web
docker build -t flask-db ./db
kubectl rollout restart deployment web
kubectl rollout restart deployment db