Fullstack Python: Deploying Flask with Docker and Google Kubernetes Engine
Cloud-native development has made deploying scalable web applications easier than ever. This blog post will guide you through deploying a fullstack Python Flask application with Docker on Google Kubernetes Engine (GKE)—a managed Kubernetes service on Google Cloud Platform (GCP) that automates deployment, scaling, and management of containerized applications.
Why Use Docker and GKE for Flask?
Consistency: Docker ensures your Flask app behaves the same in development, testing, and production.
Scalability: GKE dynamically scales your application based on demand, giving you flexibility and cost efficiency.
Reliability: Kubernetes handles service discovery, self-healing, and rolling updates, reducing downtime and manual intervention.
1. Containerizing Your Flask Application
Begin by creating a Dockerfile in your Flask project:
text
FROM python:3.9-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
EXPOSE 8080
CMD ["flask", "run", "--host=0.0.0.0", "--port=8080"]
This script installs your dependencies, copies your application code, and launches the Flask server on port 8080, which is standard for running containers in GCP.
Build and tag your image:
bash
docker build -t gcr.io/[PROJECT_ID]/flask-app:latest .
Push your image to Google Container Registry or Artifact Registry:
bash
gcloud auth configure-docker
docker push gcr.io/[PROJECT_ID]/flask-app:latest
2. Setting Up the Kubernetes Cluster on GKE
Create a cluster with the GCP CLI:
bash
gcloud container clusters create flask-cluster --num-nodes=3 --zone=[COMPUTE_ZONE]
gcloud container clusters get-credentials flask-cluster --zone=[COMPUTE_ZONE]
These commands create a cluster and configure your kubectl context.
3. Writing Kubernetes Manifests
Deployment YAML (deployment.yaml):
text
apiVersion: apps/v1
kind: Deployment
metadata:
name: flask-app
spec:
replicas: 3
selector:
matchLabels:
app: flask
template:
metadata:
labels:
app: flask
spec:
containers:
- name: flask
image: gcr.io/[PROJECT_ID]/flask-app:latest
ports:
- containerPort: 8080
Service YAML (service.yaml):
text
apiVersion: v1
kind: Service
metadata:
name: flask-service
spec:
type: LoadBalancer
selector:
app: flask
ports:
- protocol: TCP
port: 80
targetPort: 8080
The LoadBalancer service exposes your app on a public IP for external access.
4. Deploying to GKE
Apply your configurations:
bash
kubectl apply -f deployment.yaml
kubectl apply -f service.yaml
Monitor deployment status:
bash
kubectl get pods
kubectl get services
When the external IP is provisioned, you can access your Flask app from anywhere.
5. Automate with CI/CD
Integrate Google Cloud Build to automate your build and deployment process. Configure triggers to re-build and deploy on every push to your main branch, ensuring fast iteration and rollback capability.
Conclusion
With Docker and Google Kubernetes Engine, deploying Flask applications at scale becomes simple, consistent, and reliable. Embrace infrastructure-as-code, automation, and managed services to focus more on innovating and less on operations. Happy deploying
Learn FullStack Python Training
Read More : Fullstack Flask: Implementing Multi-Cloud Deployment for High Availability
Read More : Deploying Flask Apps with Kubernetes on Google Cloud
Read More : Fullstack Flask: Scaling Microservices with Kubernetes Horizontal Pod Autoscaling
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