Scott Scott - 1 year ago 40
Python Question

Google Container Engine Expose Service "Site Cannot Be Reached"

I am looking build a simple web application using Flask, Docker, and Google Container Engine. I have specified the following DockerFile:

# Use an official Python runtime as a base image
FROM python:2.7-slim

# Set the working directory to /app
WORKDIR /app

# Copy the current directory contents into the container at /app
ADD . /app

# Install any needed packages specified in requirements.txt
RUN pip install -r requirements.txt

# Make port 80 available to the world outside this container
EXPOSE 8080

# Define environment variable
ENV NAME World

# Run app.py when the container launches
CMD ["python", "app.py"]


Note I am exposing port 8080.

Here is my simple Flask application:

from flask import Flask, jsonify
from flask import make_response

app = Flask(__name__)

tasks = [
{
'type': 'order',
'contents':[1,2,3,4,5,6,7,8,9,10]
}
]

@app.route('/', methods=['GET'])
def get_tasks():
return jsonify({'tasks': tasks})

@app.errorhandler(404)
def not_found(error):
return make_response(jsonify({'error': 'Not found'}), 404)

if __name__ == '__main__':
app.run(host='0.0.0.0', port=8080)


Note
host='0.0.0.0'
and
port=8080
.

I run the docker container locally, successfully:

docker run --rm -p 8080:8080 gcr.io/${PROJECT_ID}/hello-node:v1


However, when I deploy the application using the Google Container Engine I am not able to access the application via the external port provided by
kubectl get service
.

I run the following to deploy a
Pod
:

kubectl run hello-world --image=gcr.io/${PROJECT_ID}/hello-node:v1 --port 8080


I run the following commands to create a
Service
to access from the internet:

kubectl expose deployment hello-world --type=LoadBalancer --port 8080


Why am I not able to access the service? It seems I have opened port 8080 within every step 1) Flask application 2) Dockerfile 3)
Pod
Deployment 4)
Service
creation.

Answer Source

I think you should point out the target port as well when exposing your deployment, like this:

kubectl expose deployment hello-world --type=LoadBalancer --port=8080 --target-port=8080

Hope it helps

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