What is the process of building an image in a Dockerfile?

A Dockerfile is a text file used to define the process of building a Docker image. The following outlines the general process of building an image using a Dockerfile:

1. Create an empty Dockerfile file.
2. Specify the base image using the FROM keyword. The base image can be an official image or another pre-built image.
3. Use the RUN keyword to execute commands and add new software packages, libraries, or configurations on top of the base image.
4. You can use the COPY or ADD keywords to copy local files or directories into the image.
5. Declare the port number that the container listens on using the EXPOSE keyword.
6. Specify the command or program to be executed after the container starts using the CMD or ENTRYPOINT keywords.
7. Open a terminal window in the directory where the Dockerfile is located and run the “docker build” command to build the image. For example: docker build -t . (Note that the final dot refers to the current directory).
8. Docker constructs an image based on the content and commands in the Dockerfile. Each command generates a new image layer, which are stacked together in the order they are declared.
9. After the build process is completed, you can use the command “docker images” to view the built images.
10. One option:
    You can create and run a container based on a pre-built image using the “docker run” command.

Note: During the building process, Docker will try to utilize cached image layers to improve the efficiency of the build. If any stage in the Dockerfile has changed, that stage and all subsequent layers will be rebuilt.