Docker Images

How to create our docker image?

I will containerized simple web app written by python flask.

1. OS - Ubuntu
2. Update apt repo
3. Install dependencies using apt
4. Instal Python dependencies using pip
5. Copy source code to /opt folder
6. Run the web server using “flask” command

Dockerfile according to previous this steps.

FROM Ubuntu
RUN apt-get update && apt-get -y install python
RUN pip install flask flask-mysql
COPY . /opt/source-code
ENTRYPOINT FLASK_APP=/opt/source-code/app.py flask run

Build docker image from this file with the docker build command

sudo docker build . -f Dockerfile -t numan/my-custom-app

Push the docker to docker image to make avaliable publicly

sudo docker push ahmetnuman/my-custom-app

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Demo : Creating Docker Image

• Application Source Code : https://github.com/mmumshad/simple-webapp-flask

If we installed this app on the ubuntu container steps will be like this :

anuman@dockerlabs:~$ sudo docker run -it ubuntu bash
root@2532dfc67b33:/# apt-get update -y
root@2532dfc67b33:/# apt-get install python -y
root@2532dfc67b33:/# apt-get install python3-pip -y
root@2532dfc67b33:/# pip install flask
root@2532dfc67b33:/# FLASK_APP=app.py flask run --host=0.0.0.0

we can dockerize this simple app according to these commands

• mkdir my-simple-webapp
• cd my-simple-webapp
• copy app.py codes in this directory

Dockerfile

FROM ubuntu
RUN apt-get update
RUN apt-get install -y python python3-pip
RUN pip install flask
COPY app.py /opt/app.py
ENTRYPOINT FLASK_APP=/opt/app.py flask run --host=0.0.0.0

• sudo docker build .
• sudo docker build . -t my-simple-web-app
• sudo docker images
• sudo docker run -d -p 5000:5000 my-simple-webapp

we can access web from out of the host now

curl -v <ip of the host>:5000

Pushing image to the docker hub

• sudo docker build -t 717717/mysimple-webapp
• sudo docker login
• sudo docker push 717717/my-simple-webapp