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Welcome — in this lesson you’ll deploy a simple Python/Flask application to an OpenShift Origin cluster. The demo environment consists of two parts:
  • Left: an OpenShift cluster (the web console).
  • Right: a local GitLab repository with the application source.
The Git repository contains:
  • A Flask application file (.py) that serves a simple web page.
  • A requirements.txt file listing dependencies (e.g., Flask).
This guide walks through deploying the app using OpenShift’s web console (source-to-image / S2I workflow), monitoring the build, and exposing the application via a route.

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Step-by-step: Deploy the Flask app

  1. Log in to the OpenShift web console as a developer.
  2. Create a new project: click Create Project and provide a descriptive name.
  3. Open the new project from the project list to view its Project Console.
  4. Click Browse Catalog to see builders and templates available in the cluster.
  5. Choose the Python builder image because the app uses Python/Flask.
A screenshot of the OpenShift Origin web console with a modal dialog for the Python builder image. The dialog shows the Python logo and brief info about building Python 3.6 on CentOS 7, with navigation buttons like Cancel and Next.
  1. In the creation wizard, provide:
    • An application name (for example simple-webapp)
    • The Git repository URL (copy the URL from your GitLab repository)
    • Any environment variables or build options you need
  2. Click Next (or Create) to start the build. OpenShift will create a BuildConfig and kick off a source-to-image build from your Git repository.
OpenShift creates a BuildConfig automatically when you deploy from a Git repository. The S2I (source-to-image) process clones your repo, installs dependencies from requirements.txt, builds the image, and pushes it into the cluster registry.

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Monitor the build and image push

After the build starts, the Overview and Builds pages show build progress. To inspect build output, go to the Builds section and open the build log (View Log). The log typically shows:
  • Git clone of your repository
  • Installation of Python dependencies from requirements.txt
  • S2I layers assembling the application image
  • The image push to the internal registry
Example build log (condensed):

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What OpenShift creates for you

When the image push finishes, OpenShift typically creates these runtime artifacts:

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Verify the deployment and open the app

On the Overview page you can view:
  • The Build and BuildConfig
  • The DeploymentConfig and Replica status
  • Networking information (exposed port such as 8080, and the Route)
A screenshot of the OpenShift Origin web console showing the "My WebApplication" project and the "simple-webapp" application. The page shows deployment details (image, build), networking (port 8080 and route), and a status donut indicating 1 pod.
Click the Route URL to open the application in a browser. That public route is the endpoint to share with your users.

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Next steps and further reading

This demo demonstrates a basic single-container deployment using OpenShift S2I. Typical follow-ups include:
  • Deploying multi-tier applications (front-end, API, database)
  • Composing microservices and adding health checks, probes, and readiness checks
  • Automating builds and deployments with CI/CD (e.g., GitLab CI)
  • Securing routes and configuring TLS termination
Links and references:

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