CODEWITHSUNDEEP
dockerflaskkuberneteskubectlminikube
Tanuj Dutta
Tanuj Dutta

Reputation: 1

Flaskapp is not running in desired port in Minikube Cluster

I am running a very basic blogging app using Flask. Its runs fine when I run it using Docker i.e. docker run -it -d -p 5000:5000 app.

 * Serving Flask app 'app' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on all addresses.
   WARNING: This is a development server. Do not use it in a production deployment.
 * Running on http://10.138.0.96:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 144-234-816

This runs on my localhost:5000 just fine.

But when I deploy this in Minikube, it says

This site can’t be reached 34.105.79.215 refused to connect.

I use this workflow in Kubernetes

$ eval $(minikube docker-env)
$ docker build -t app:latest .
$ kubectl apply -f deployment.yaml (contains deployment & service)

kubectl logs app-7bf8f865cc-gb9fl returns

* Serving Flask app "app" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on all addresses.
   WARNING: This is a development server. Do not use it in a production deployment.
 * Running on http://172.17.0.3:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 713-503-298

Dockerfile

FROM ubuntu:18.04

WORKDIR /app

COPY . /app

RUN apt-get update && apt-get -y upgrade

RUN apt-get -y install python3 && apt-get -y install python3-pip

RUN pip3 install -r requirements.txt

EXPOSE 5000

ENTRYPOINT ["python3"]

CMD ["app.py"]

deployment.yaml

apiVersion: v1
kind: Service
metadata:
   name: app-service
spec:
   selector:
      app: app
   ports:
   - protocol: "TCP"
     port: 5000
     targetPort: 5000
   type: LoadBalancer

---
apiVersion: apps/v1
kind: Deployment
metadata:
   name: app
spec:
   selector:
      matchLabels:
         app: app
   replicas: 1
   template:
      metadata:
         labels:
            app: app
      spec:
         containers:
         - name: app
           image: app:latest
           imagePullPolicy: Never
           ports:
           - containerPort: 5000

Also I noticed that on running from Docker container when I do docker ps I get PORTS as 0.0.0.0:5000->5000/tcp but the kubernetes ports shows 127.0.0.1:32792->22/tcp, 127.0.0.1:32791->2376/tcp, 127.0.0.1:32790->5000/tcp, 127.0.0.1:32789->8443/tcp, 127.0.0.1:32788->32443/tcp

Upvotes: 0

Views: 184

Answers (1)

coderanger
coderanger

Reputation: 54267

The port: on a Service only controls the internal port, the one that's part of the ClusterIP service. By default the node port is randomly assigned from the available range. This is because while the port value only has to be unique within the Service itself (couldn't have the same port go to two places, would make no sense), node ports are a global resource and have to be globally unique. You can override it via nodePort: whatever in the Service definition but I wouldn't recommend it.

Minikube includes a helper to manage this for you, run minikube service app-service and it will load the URL in your browser mapped through the correct node port.

Upvotes: 3

Related Questions