Containerization versus virtualization

Different tools, such as Docker and Vagrant, seem to overlap in features – but the main difference between them is the reason why these tools were built. Vagrant, as we mentioned earlier, is built primarily as a tool for development. It allows us to bootstrap the whole virtual machine with a single command, but does not allow us to simply pack such an environment as a complete deliverable artifact and deploy or release it. Docker, on the other hand, is built exactly for that purpose – preparing complete containers that can be sent and deployed to production as a whole package. If implemented well, this can greatly improve the process of product deployment. Because of that, using Docker and similar solutions (Rocket for example) during development only makes more sense if such containers are also to be used in the deployment process on production.

Due to some implementation nuances, the environments that are based on containers may sometimes behave differently than environments based on virtual machines. If you decide to use containers for development, but don't decide to use them on target production environments, you'll lose some of the consistency guarantees that were the main reason for environment isolation. But, if you already use containers in your target production environments, then you should always replicate production conditions rather than using the same technique. Fortunately, Docker, which is currently the most popular container solution, provides an amazing docker-compose tool that makes the management of local containerized environments extremely easy.

Let's write our first Dockerfile in the next section.