A Dockerfile is a simple text file without any extension that allows a user to define instructions that would be executed while building an image. When we run the docker build command, the daemon looks for the dockerfile inside the build context and starts executing the instructions inside it one by one. Usually, the first instruction inside a dockerfile is the FROM instruction.
You can use this instruction to pull a base image, and each instruction after that adds a new intermediate image layer on top of the base image. It's quite important to understand the build cache mechanism that the build process uses to write the instructions in the best possible sequence.
Instructions should be written in such a way that the least frequently changing instruction is at the top and the one which changes frequently is at the bottom. This ensures that the build process can utilize the cache from the previous build to save time and resources.
