Deploying a Python app to Openshift 4 using s2i

S2I or Source to Image, is a way to deploy application from its sourcecode directly to Openshift. In this article, we try to build a Python apps with Flask framework and deploy it to Openshift.

So lets start with requirements.txt for storing required libraries

flask

And a simple hello world app

from flask import Flask

app = Flask(__name__)

@app.route("/")
def index():
    return "<h1>Hello, World!</h1>"

app.run(host="0.0.0.0", port=8080)

Next is where the magic happens, it would build, containerized and push the whole apps to external registry by using below commands,

$ oc new-build . --name=hello-world-python --to-docker --to=docker.io/dockerusername/hello-world-python

$ oc start-build hello-world-python --from-dir=. --follow --wait

Once we push it to external registry, we can pull and run the apps in Openshift

$ oc new-app . --docker-image=dockerusername/hello-world-python --name=hello-world-python-app

And expose a secure URL for it,

$ oc create route edge --service=hello-world-python-app

Code for this can be accessed here,

https://github.com/edwin/hello-world-flask