If you haven't installed Docker, then install it on your machine using the link (
Installing Docker on Ubuntu).
Define a container with Dockerfile
Now its time to create your own custom environment using DockerFile. DockerFile behaves exactly the same wherever it runs enabling you to establish same standard configuration on dev, test and production environment.
Step 1: Create a folder (in my case i have created my-docker-img folder)
Step 2: Create a Dockerfile inside the folder (I have created Dockerfile.txt)
Dockerfile.txt
# Use an official Python runtime as a parent 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
# Set proxy server, replace host:port with values for your servers (If your are behind proxy server)
#ENV http_proxy host:port
#ENV https_proxy host:port
# Install any needed packages specified in requirements.txt
RUN pip install --trusted-host pypi.python.org -r requirements.txt
# Make port 80 available to the world outside this container
EXPOSE 80
# Define environment variable
ENV NAME World
# Run app.py when the container launches
CMD ["python", "app.py"]
Step 3: Create app.py and requirement.txt specified in Docker file in the same folder.
app.py file is your python application that you want to deploy
app.py
from flask import Flask
from redis import Redis, RedisError
import os
import socket
# Connect to Redis
redis = Redis(host="redis", db=0, socket_connect_timeout=2, socket_timeout=2)
app = Flask(__name__)
@app.route("/")
def hello():
try:
visits = redis.incr("counter")
except RedisError:
visits = "<i>cannot connect to Redis, counter disabled</i>"
html = "<h3>Hello {name}!</h3>" \
"<b>Hostname:</b> {hostname}<br/>" \
"<b>Visits:</b> {visits}"
return html.format(name=os.getenv("NAME", "world"), hostname=socket.gethostname(), visits=visits)
if __name__ == "__main__":
app.run(host='0.0.0.0', port=80)
requirements.txt
Flask
Redis
Note:
When the Dockerfile is built into an image, Dockerfile’s ADD command will add app.py into the image, and the app is served over HTTP with help the EXPOSE command which expose port 80. PIP command install python dependency libraries specified on requirements.txt file
Build the app
Now execute the build command from top of the directory. This creates a Docker image with tag using -t so it has a friendly name.
In my case directory is
/Documents/my-docker-img and image name is
my-app
docker build -t my-app .
To view the list images created on your machine
docker image ls
Run the app
Run the app, by mapping your machine’s port 8000 to the container’s published port 80 using -p
docker run -p 4000:80 friendlyhello
Then you can access your app deployed within the container using following URL
http://localhost:8000/
If you want to run the container in the background in detach mode
docker run -d -p 4000:80 my-app
To view all the running containers on your machine
docker container ls
If you want to stop the running container using CONTAINER ID
sudo docker container stop c1081125c6e9
Next Share your docker image
Useful links
https://docs.docker.com/get-started/part2/#log-in-with-your-docker-id
