Dockerfile vs. docker-compose.yml: What’s the Difference?

If you’re new to the world of Docker, you may be wondering what the difference is between a Dockerfile and a docker-compose.yml file. In this blog post, we will discuss the differences between these two files and explain how they can be used to create and run Docker applications.

What do you do when you need to deploy Docker containers, where do you start? You could deploy the containers via the command line, with a string of command options for each one. However, that would get tedious quickly. Alternatively, you can use a tool that lets you configure the deployment in a configuration file and then launch the container.

However, what configuration file is the best to use? What is the best deployment method? Do you choose docker-compose or dockerfile, or both? Determining which to use depends a lot on the complexity of the services or applications you intend to deploy.  

The Difference Between docker-compose.yml & Dockerfile

What Is a docker-compose.yml File?

The docker-compose.yml file is a configuration file that lets you define and run multiple Docker containers using a single file. This file uses the YAML syntax, which is a human-readable data serialization format. The docker-compose.yml file can be used to deploy both stateless and stateful applications. You would use docker-compose.yml files if you wanted to launch a LAMP stack, you could define the webserver (Apache or Nginx) and add a database (MySQL or MariaDB) within the docker-compose.yml file. Other services like Podman can also use Docker Compose.

What Is a Dockerfile?

The Dockerfile is a text file that contains all the commands needed to build a Docker image. An automated build can be created by executing several command-line instructions in succession using a Dockerfile. Docker was written in Go and relies on several Linux kernel features to deliver its features. The Dockerfile can be used to deploy both stateless and stateful applications, but it is typically used for deploying stateless applications. Dockerfiles contain specific commands that explain how to create Docker images. A Dockerfile can include the following commands:

FROM, PULL, RUN, and CMD

So, which should you use? If you are deploying a stateless application, then the Dockerfile is the best option. If you are deploying a stateful application, then the docker-compose.yml file is the best option. However, if you are not sure which type of application you are deploying, then it is safest to use the docker-compose.yml file. This file will work for both stateless and stateful applications.

In summary, the docker-compose.yml file is a configuration file that lets you define and run multiple Docker containers using a single command. The Dockerfile is a text file that contains all the commands needed to build a Docker image. These two files can be used together to create and run Docker applications.

Now that you understand the difference between a Dockerfile and a docker-compose.yml file, you can choose the best option for your needs.