stevenacoffman/flask_kubernetes_example repository overview

⁠Example Flask app with Prometheus on Kubernetes

See src for the application code.

Note: Adapted for Kubernetes from Swarm example code here: python-prometheus-demo⁠. Original swarm prometheus article⁠ here.

Run this locally in docker:

docker run -p 8888:8888 stevenacoffman/flask_kubernetes_example

Apply this to your Kubernetes cluster (Note: cluster not included):

kubectl apply -f flask-example.yaml

⁠Building Docker image

The Python 3 based Dockerfile⁠ uses an Alpine Linux base image and expects the application source code to be volume mounted at /application when run:

FROM python:3.6.1-alpine
ADD . /application
WORKDIR /application
RUN set -e; \
	apk add --no-cache --virtual .build-deps \
		gcc \
		libc-dev \
		linux-headers \
	; \
	pip install -r src/requirements.txt; \
	apk del .build-deps;
EXPOSE 8888
VOLUME /application
CMD uwsgi --http :8888  --manage-script-name --mount /application=flask_app:app --enable-threads --processes 5

The last statement shows how we are running the application via uwsgi with 5 worker processes.

To build the image:

$ docker build -t stevenacoffman/flask_kubernetes_example .

⁠Running the application

We can just run the web application as follows:

$ docker run  -ti -p 8888:8888 stevenacoffman/flask_kubernetes_example

⁠Running the application via Docker compose

See the compose directory for a way to run the flask app and a prometheus server locally via docker compose

⁠Running the application via Kubernetes

$ kubectl apply -f flask-k8s.yaml