How to deploy Flask to AWS

Deploy Flask with Gunicorn on ECS Fargate behind an Application Load Balancer.

Prerequisites

A Git repository containing your application and its production build command.
A Ravion account with your AWS account connected. Start free at Ravion signup.
The Ravion CLI installed and authenticated. See CLI installation.

The examples use my-org/my-app as a placeholder. Replace it with your repository before applying the config.

Set up this Flask app for Ravion ECS hosting.

Configure the deployment

Flask’s production documentation recommends a dedicated WSGI server instead of the built-in development server. This example uses Railpack for the build. Use build_source: dockerfile instead when you need a custom Dockerfile. Railpack detects Flask from the application dependencies. Railpack detects Flask when flask is a dependency. It starts gunicorn --bind 0.0.0.0:${PORT:-8000} main:app only when gunicorn is also a dependency, so add Gunicorn to your requirements and use a custom start command when your module or application factory differs from main:app. Ravion injects PORT automatically from container_port.

ravion.yaml

project:
  givenId: flask-app
  name: Flask app
environments:
  - givenId: production
    name: Production
    moduleInstances:
      - givenId: network
        name: Network
        type: rvn-aws-network
        version: 1.0.0
        input:
          aws_account_id: ravion-prod
          aws_region: us-east-1
          name: flask-production
      - givenId: cluster
        name: ECS cluster
        type: rvn-ecs-cluster
        version: 1.0.0
        input:
          network:
            moduleGivenIdRef: network
          name: flask-production
      - givenId: web
        name: Flask web service
        type: rvn-ecs-web
        version: 1.0.0
        input:
          cluster:
            moduleGivenIdRef: cluster
          name: flask-production-web
          build_source: railpack
          source_repo: my-org/my-flask-app
          container_port: 8000
          fargate_size:
            vcpu: 0.5
            memory_gb: 1

Gunicorn binds to port 8000 in this example. Use your application factory import path if the app is created by a function.

Apply and connect your domain

ravion project create --given-id flask-app --name "Flask app"
ravion project config apply flask-app --file ravion.yaml --dry-run
ravion project config apply flask-app --file ravion.yaml

Follow custom domains to connect your domain to the Application Load Balancer.

Next steps

Custom domains

Point a domain at your deployed service and manage its certificate.

Project config

Preview and apply Ravion configuration from source control.

Pipelines

Add approvals, migrations, and deployment automation.

Logs and metrics

Inspect deploy output and production health in Ravion.

​Prerequisites

​Configure the deployment

​Apply and connect your domain

​Next steps