Python Flask App with Istio Integration

This project is a simple Flask web application deployed in Kubernetes using Istio for traffic management and monitoring.

Project Structure

---

├── Makefile
├── README.md
├── kustomization.yaml
├── patches
│   ├── grafana-cm.yaml
│   └── kustomization.yaml
├── python-app
│   ├── Dockerfile
│   ├── app.py
│   ├── k8s
│   │   ├── base
│   │   │   ├── app-service.yaml
│   │   │   ├── ingressgateway-istio.yaml
│   │   │   ├── kustomization.yaml
│   │   │   ├── v1
│   │   │   │   └── app-deployment-v1.yaml
│   │   │   ├── v2
│   │   │   │   └── app-deployment-v2.yaml
│   │   │   └── v3
│   │   │       └── app-deployment-v3.yaml
│   │   ├── destination-rule.yaml
│   │   ├── kustomization.yaml
│   │   ├── security
│   │   │   ├── auth-policy.yaml
│   │   │   ├── kustomization.yaml
│   │   │   └── peer-authentication.yaml
│   │   └── vs.yaml
│   └── templates
│       └── index.html
└── tests
    └── h2load.sh

• app.py - Main Flask application file.
• Dockerfile - Docker image for the application.
• templates/index.html - HTML template for the homepage.
• Makefile - Automation scripts for tasks like starting Minikube, installing Istio, and deploying the app.
• k8s/ - Kubernetes manifests for deploying the application.
• tests/h2load.sh - Script for performance testing.
• patches - Patch ConfigMap to access grafana dashboard using istio VirtualService.

Requirements

---

• Python 3.11
• Docker
• Minikube
• Istio
• Kubernetes CLI (kubectl)
• Istio CLI (istioctl)

Installation and Usage

---

1. Start Minikube

make start-minikube

2. Install Istio

make install-istio

3. Build Docker Image (optional)

You can build the Docker image for the application using the provided Dockerfile. The Dockerfile is located in the python-app directory.

docker build -t istio-python-app:latest python-app/
docker tag istio-python-app:latest <your-registry>/istio-python-app:latest
docker push <your-registry>/istio-python-app:latest

And then change the image name in the deployments files located in python-app/k8s/base/ (v1, v2, v3 folders) to match your registry.

4. Deploy the Application to Kubernetes

make create-python-app

5. Forward istio-ingressgateway port

kubectl port-forward -n istio-system service/istio-ingressgateway 8080:80

Accessing the Application

---

After deployment, the application will be accessible via the Istio Ingress Gateway. To get access by URL add the following into the /etc/hosts file:

127.0.0.1       example.local

Then, you can access the application using the following URL:

http://example.local:8080/app

To access the grafana dashboard you can use the following URL:

http://example.local:8080/grafana

To access the Kiali dashboard, you can use the following URL:

http://example.local:8080/kiali

You can also access to the API endpoint using the following command:

curl -H "Authorization: Bearer my-static-token-123" http://example.local:8080/app/api

Testing the application

---

To test the application, you can use the h2load.sh script located in the tests directory. This script uses h2load to perform load testing on the application. Use the following command to run the test:

make test-python-app

Monitoring

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• Prometheus: Application metrics.
• Kiali: Visualization of network traffic.