Can you list the main steps for creating a Dockerfile?

Main steps for creating a Dockerfile:

1. Choose a base image — specify which image your container will inherit from, for example, python:3.9.
2. Copy files — use the COPY command to transfer necessary files and directories into the container.
3. Install dependencies — use RUN to install required packages, for example, pip install -r requirements.txt.
4. Set the working directory — use WORKDIR to define the directory inside the container.
5. Define the startup command — use CMD or ENTRYPOINT to specify the command that will run when the container starts.

Example of a simple Dockerfile for a Python application:

FROM python:3.9
WORKDIR /app
COPY requirements.txt ./
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "app.py"]