Docker (containerization) vs Vagrant (virtual machine) 🌱

• What if you can run an application on your machine, but someone on another machine can’t?
• If you want to manage machines, you should use Vagrant. If you want to build and run applications environments, you should use Docker. Vagrant is a tool for managing virtual machines. Docker is a tool for building and deploying applications by packaging them into lightweight containers.

Vagrant

• Say you start with a fresh virtual machine, then you have a “provisioning script” which installs on the virtual machine all the extra software you need to run your application.
• This “provisioning script” is also run on the staging server (server for development/testing) and production server (server to publish finished application) so that anyone can inintialize a virtual machine and run your application.
• Now, someone can just take your project code from github and run your application from any virtual machine as long as they use the “provisioning script” to install everything.

Docker

• Docker uses a “dockerfile” to convert your project code and all installation requirements into a “docker image” (this image is essentially everything you need to run your application).
• You then run this “docker image” as something called a “container”, and you can run as many of these “containers” as you want on a single virtual machine (as long as you don’t run out of memory).
• You store your “docker image” on essentially a docker version of Github (like Docker Hub) and now any machine with Docker can run your applicatino using the “docker image”.
• Amazon’s “ECS” (EC2 (elastic compute cloud) Container Service) platform can manage your containers for you.
• Containers reuse the kernel the hosting OS. Most of the containers available out there are based on Linux, so they need to have access a Linux kernel for them to run. Therefore, if you’re on Windows and want to run one you would need to install a Linux VM and run the containers in the VM.