Manual Image Build Process

For learning purpose, we're making a manual docker image. The term "best practice" relates to the process of creating an automated image. If we create a manual image in Docker, we must keep it up to date as our source code changes. As a consequence, the Process needs a significant amount of time and effort.
OS: Unix systems ( Ubuntu )

In the container, we'll run a simple flask application. We'll create an Image from a container once it's ready.

1) create a directory
below created a manual-build directory in the host

$/home/usr/Desktop/Docker/manual-build

2) Open the manual-build folder in the IDE or text editor. To write source code.

3) create two different files.
For example,

1) myfirst.py, to write minimal flask code inside it.( Hello_world )

2) start-app.sh, a script that will execute in the Image.

4) make a container with a base image python

sudo docker create -it --name manual -p 5002:5002 python /bin/sh

The given interactive container(-it) name is manual which runs at port 5002.

5) start a python container( manual ) and open a shell.

sudo docker start -i manual

6) In the python base container, add /app dir

once /app dir is created exit from the shell and it will get back to host directory where manual-build folder is located.

7) Copy flask.py from the manual-build folder to the docker/app directory.

8) Copy the start-app.py file from the manual-build folder to the docker/app directory.

The following command will copy files from the host to container.

sudo docker cp myfirst.py manual:/app

sudo docker cp start-app.sh manual:/app

9) Restart the container and double-check.

sudo docker start -i manual

cd /app

ls -l

10) Write the.sh script's execution.

chmod +x start-app.sh

11) Install the flask inside the container.

pip install flask

Once, flask is installed in the container then execute start-app.sh script with following command.

./start-app.sh or sh start-app.sh

The flask application works perfectly as we expected with port 5000.Container(manual ) is ready to ship.

12) create an image from a ready container

Once, container is ready. use commit in the docker to create new custom image

Sudo docker commit manual manual-image:1.1

manual-image is name of new custom image and 1.1 tag is given to it.

13) Run the newly formed image

Again, execute start-app.sh script in the manual-build:1.1 image. Now, Image works perfectly in the browser with given IP http://172.17.0.2:5000/