Fullstack Python: Deploying Flask with Docker and Google Kubernetes Engine

July 21, 2025

Building scalable, reliable web applications requires more than just solid backend logic—it also involves smart deployment strategies. Flask, a popular Python microframework, is an excellent choice for developing fullstack web apps due to its simplicity and flexibility. When combined with Docker and Google Kubernetes Engine (GKE), Flask becomes highly portable and scalable, making it ideal for production environments. In this blog, we’ll walk through how to deploy a Flask app using Docker and GKE.

Why Use Docker and GKE?

Docker allows you to containerize your Flask application, meaning it can run reliably across different environments without worrying about dependencies. Google Kubernetes Engine (GKE) is a managed Kubernetes service that simplifies container orchestration, scaling, and deployment on Google Cloud Platform (GCP).

Together, Docker and GKE offer:

Consistency across environments

Auto-scaling and self-healing features

Efficient resource management

Easy rollouts and rollbacks

Step 1: Build Your Flask Application

Let’s assume you have a basic Flask application:

python

# app.py

from flask import Flask

app = Flask(__name__)

@app.route('/')

def hello():

return "Hello from Flask on GKE!"

You should also include a requirements.txt file:

ini

Flask==2.3.2

gunicorn==21.2.0

Step 2: Create a Dockerfile

Containerize your Flask app by writing a Dockerfile:

Dockerfile

FROM python:3.11-slim

WORKDIR /app

COPY requirements.txt .

RUN pip install -r requirements.txt

COPY . .

CMD ["gunicorn", "-b", "0.0.0.0:8080", "app:app"]

Build and tag the image:

bash

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docker build -t flask-gke-app .

Step 3: Push Image to Google Container Registry (GCR)

Tag the image and push it to GCR:

bash

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docker tag flask-gke-app gcr.io/YOUR_PROJECT_ID/flask-gke-app

docker push gcr.io/YOUR_PROJECT_ID/flask-gke-app

Replace YOUR_PROJECT_ID with your GCP project ID.

Step 4: Set Up GKE Cluster

Enable the Kubernetes Engine API in your GCP console.

Create a cluster using the GCP Console or CLI:

bash

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gcloud container clusters create flask-cluster --num-nodes=2

gcloud container clusters get-credentials flask-cluster

Step 5: Deploy Flask App to GKE

Create a deployment YAML file:

yaml

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# deployment.yaml

apiVersion: apps/v1

kind: Deployment

metadata:

name: flask-app

spec:

replicas: 2

selector:

matchLabels:

app: flask-app

template:

metadata:

labels:

app: flask-app

spec:

containers:

- name: flask-app

image: gcr.io/YOUR_PROJECT_ID/flask-gke-app

ports:

- containerPort: 8080

Then, apply it:

bash

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kubectl apply -f deployment.yaml

Expose it with a LoadBalancer:

bash

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kubectl expose deployment flask-app --type=LoadBalancer --port=80 --target-port=8080

Use kubectl get service to find the external IP.

Conclusion

Deploying a Flask app with Docker and GKE streamlines the process of moving from development to production. Docker ensures consistency, while GKE handles orchestration and scaling. This setup is ideal for teams building fullstack Python applications that require high availability and rapid deployment capabilities.

Whether you're building a SaaS product, an internal tool, or a microservice, Flask + Docker + GKE is a modern stack that supports scalability, reliability, and developer productivity.

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